TW201843572A - Light sensing circuit - Google Patents
Light sensing circuit Download PDFInfo
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- TW201843572A TW201843572A TW106114743A TW106114743A TW201843572A TW 201843572 A TW201843572 A TW 201843572A TW 106114743 A TW106114743 A TW 106114743A TW 106114743 A TW106114743 A TW 106114743A TW 201843572 A TW201843572 A TW 201843572A
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/51—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used
- H03K17/56—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices
- H03K17/687—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the components used by the use, as active elements, of semiconductor devices the devices being field-effect transistors
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K17/00—Electronic switching or gating, i.e. not by contact-making and –breaking
- H03K17/94—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated
- H03K17/941—Electronic switching or gating, i.e. not by contact-making and –breaking characterised by the way in which the control signals are generated using an optical detector
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03K—PULSE TECHNIQUE
- H03K2217/00—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00
- H03K2217/94—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00 characterised by the way in which the control signal is generated
- H03K2217/941—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00 characterised by the way in which the control signal is generated using an optical detector
- H03K2217/94116—Indexing scheme related to electronic switching or gating, i.e. not by contact-making or -breaking covered by H03K17/00 characterised by the way in which the control signal is generated using an optical detector increasing reliability, fail-safe
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Abstract
Description
本發明是有關於一種光感測電路,且特別是有關於一種有效降低環境光干擾的光感測電路。The present invention relates to a light sensing circuit, and more particularly, to a light sensing circuit that effectively reduces ambient light interference.
光感測電路可以用於光學式觸控裝置,可藉由設置濾光元件而達到對特定色光感測的效果。然而,由於環境光具有各種顏色的頻率成份,於感測特定色光時,可能會受到環境光的干擾而導致錯誤發生。因此,如何實現抗環境光干擾的特定色光感測電路,乃目前業界致力課題之一。The light sensing circuit can be used in an optical touch device, and a filter element can be provided to achieve a specific color light sensing effect. However, since the ambient light has frequency components of various colors, when sensing a specific colored light, it may be interfered by the ambient light and cause errors. Therefore, how to implement a specific color light sensing circuit that is resistant to ambient light interference is one of the current major issues in the industry.
本發明係有關於一種光感測電路,可對於特定色光感測,排除環境光的干擾,並能夠提升畫素之開口率。The invention relates to a light-sensing circuit, which can detect specific color light, eliminate the interference of ambient light, and improve the aperture ratio of pixels.
根據本發明之一方面,提出一種光感測電路。光感測電路包括第一感光元件、第二感光元件、第三感光元件、第四感光元件、電容、取樣電路、第一開關元件、以及第二開關元件。第一感光元件具有第一端及第二端,第一感光元件被第一濾光元件覆蓋,第一濾光元件係用以通過第一色光。電容電性耦接於第一感光元件的第一端與電壓源之間。取樣電路電性耦接於第一感光元件的第一端。第二感光元件具有第一端及第二端,第二感光元件的第二端電性耦接於第一感光元件的第二端,第二感光元件的第一端電性耦接電壓源,第二感光元件被第二濾光元件覆蓋,第二濾光元件係用以通過第二色光。第三感光元件具有第一端及第二端,第三感光元件的第二端用以接收第一控制信號,第三感光元件被第三濾光元件覆蓋。第四感光元件具有第一端及第二端,第四感光元件的第二端用以接收第二控制信號,第四感光元件被第四濾光元件覆蓋,第四濾光元件係用以通過第一色光。第一開關元件電性耦接於第一感光元件的第二端與第三感光元件的第一端之間,第一開關元件回應於第一控制信號與第二控制信號其中之一者選擇性地導通。第二開關元件電性耦接於第一感光元件的第二端與第四感光元件的第一端之間,第二開關元件回應於第一控制信號與第二控制信號其中之另一者選擇性地導通。According to an aspect of the present invention, a light sensing circuit is provided. The light sensing circuit includes a first photosensitive element, a second photosensitive element, a third photosensitive element, a fourth photosensitive element, a capacitor, a sampling circuit, a first switching element, and a second switching element. The first photosensitive element has a first end and a second end. The first photosensitive element is covered by a first filter element. The first filter element is used to pass light of a first color. The capacitor is electrically coupled between the first end of the first photosensitive element and the voltage source. The sampling circuit is electrically coupled to the first end of the first photosensitive element. The second photosensitive element has a first end and a second end, the second end of the second photosensitive element is electrically coupled to the second end of the first photosensitive element, and the first end of the second photosensitive element is electrically coupled to a voltage source, The second photosensitive element is covered by a second filter element, and the second filter element is used to pass light of a second color. The third photosensitive element has a first end and a second end. The second end of the third photosensitive element is used to receive a first control signal. The third photosensitive element is covered by a third filter element. The fourth photosensitive element has a first end and a second end. The second end of the fourth photosensitive element is used to receive a second control signal. The fourth photosensitive element is covered by a fourth filter element. The fourth filter element is used to pass through. First color light. The first switching element is electrically coupled between the second end of the first photosensitive element and the first end of the third photosensitive element. The first switching element is selectively responsive to one of the first control signal and the second control signal. Ground is on. The second switching element is electrically coupled between the second end of the first photosensitive element and the first end of the fourth photosensitive element. The second switching element is selected in response to the other of the first control signal and the second control signal. By nature.
為了對本發明之上述及其他方面有更佳的瞭解,下文特舉實施例,並配合所附圖式詳細說明如下:In order to have a better understanding of the above and other aspects of the present invention, the following specific examples are described in detail below in conjunction with the accompanying drawings:
第1圖繪示依照本發明第一實施例的光感測電路100示意圖。在此實施例中,光感測電路100包括第一感光元件T1、第二感光元件T2、第三感光元件T3、第四感光元件T4、電容C1、取樣電路TSH 、第一開關元件TSW1 、以及第二開關元件TSW2 。第一感光元件T1具有第一端及第二端,第一感光元件T1被第一濾光元件CF1覆蓋,第一濾光元件CF1係用以通過第一色光(通常指一特定波長範圍的光線相較於範圍外的光線,能夠明顯地容易通過濾光元件)。電容C1電性耦接於第一感光元件T1的第一端與電壓源VSH 之間。取樣電路TSH 電性耦接於第一感光元件T1的第一端。第二感光元件T2具有第一端及第二端,第二感光元件T2的第二端電性耦接於第一感光元件T1的第二端,第二感光元件T2的第一端電性耦接電壓源VSH ,第二感光元件T2被第二濾光元件CF2覆蓋,第二濾光元件CF2係用以通過第二色光。第三感光元件T3具有第一端及第二端,第三感光元件T3的第二端用以接收第一控制信號Sn1(t),第三感光元件T3被第三濾光元件CF3覆蓋。第四感光元件T4具有第一端及第二端,第四感光元件T4的第二端用以接收第二控制信號Sn2(t),第四感光元件T4被第四濾光元件CF4覆蓋,第四濾光元件CF4係用以通過第一色光。第一開關元件TSW1 電性耦接於第一感光元件T1的第二端與第三感光元件T3的第一端之間,第一開關元件TSW1 回應於第一控制信號Sn1(t)與第二控制信號Sn2(t)其中之一者選擇性地導通。第二開關元件TSW2 電性耦接於第一感光元件T1的第二端與第四感光元件T4的第一端之間,第二開關元件TSW2 回應於第一控制信號Sn1(t)與第二控制信號Sn2(t)其中之另一者選擇性地導通。在第1圖所示的實施例,第一開關元件TSW1 受控於第二控制信號Sn2(t),第二開關元件TSW2 受控於第一控制信號Sn1(t),在另一實施例中,可以是第一開關元件TSW1 受控於第一控制信號Sn1(t),第二開關元件TSW2 受控於第二控制信號Sn2(t)。FIG. 1 is a schematic diagram of a light sensing circuit 100 according to a first embodiment of the present invention. In this embodiment, the light sensing circuit 100 includes a first photosensitive element T1, a second photosensitive element T2, a third photosensitive element T3, a fourth photosensitive element T4, a capacitor C1, a sampling circuit T SH , and a first switching element T SW1. And a second switching element T SW2 . The first photosensitive element T1 has a first end and a second end. The first photosensitive element T1 is covered by a first filter element CF1. The first filter element CF1 is used to pass a first color light (usually refers to a specific wavelength range). The light can pass through the filter element more easily than the light outside the range). The capacitor C1 is electrically coupled between the first terminal of the first photosensitive element T1 and the voltage source V SH . The sampling circuit T SH is electrically coupled to the first terminal of the first photosensitive element T1. The second photosensitive element T2 has a first end and a second end. The second end of the second photosensitive element T2 is electrically coupled to the second end of the first photosensitive element T1. The first end of the second photosensitive element T2 is electrically coupled. Connected to the voltage source V SH , the second photosensitive element T2 is covered by the second filter element CF2, and the second filter element CF2 is used to pass the second color light. The third photosensitive element T3 has a first end and a second end. The second end of the third photosensitive element T3 is used to receive the first control signal Sn1 (t). The third photosensitive element T3 is covered by the third filter element CF3. The fourth photosensitive element T4 has a first end and a second end. The second end of the fourth photosensitive element T4 is used to receive the second control signal Sn2 (t). The fourth photosensitive element T4 is covered by the fourth filter element CF4. The four filter elements CF4 are used to pass the first color light. The first switching element T SW1 is electrically coupled between the second end of the first photosensitive element T1 and the first end of the third photosensitive element T3. The first switching element T SW1 is responsive to the first control signal Sn1 (t) and One of the second control signals Sn2 (t) is selectively turned on. The second switching element T SW2 is electrically coupled between the second end of the first photosensitive element T1 and the first end of the fourth photosensitive element T4. The second switching element T SW2 is responsive to the first control signal Sn1 (t) and The other of the second control signals Sn2 (t) is selectively turned on. In the embodiment shown in FIG. 1, the first switching element T SW1 is controlled by the second control signal Sn2 (t), and the second switching element T SW2 is controlled by the first control signal Sn1 (t). In another implementation, For example, the first switching element T SW1 may be controlled by the first control signal Sn1 (t), and the second switching element T SW2 may be controlled by the second control signal Sn2 (t).
在第1圖所示的範例中,第一感光元件~第四感光元件T1~T4係以電晶體作為範例說明,例如是使用金屬氧化物半導體場效電晶體(MOSFET)或氧化物半導體場效電晶體,如薄膜電晶體(Thin Film Transistor, TFT),而在圖中以NMOS電晶體(例如N型TFT)作為例子說明。然而,第一感光元件~第四感光元件T1~T4的實作範例並不限於此,例如亦可以使用PMOS電晶體、其他不同類型的電晶體、或是光電二極體(Photodiode)等等。以光電二極體為例,通常被設計為工作在逆向偏壓狀態(Reverse Biased),當一個具有充足能量的光子衝擊到二極體上,可以產生光電流(Photocurrent),因此能夠達到感光效果。如第1圖所示的第一感光元件~第四感光元件T1~T4,各個電晶體的第二端(例如是汲極,電晶體的汲極與源極需視電壓高低而決定,此處為舉例說明)與控制端(例如是閘極)相連接,而形成二極體連接形式(Diode Connected),因此與前述的逆向偏壓光電二極體操作原理類似。當電晶體的控制端給予非導通控制信號時(以NMOS電晶體為例,當控制端給予低邏輯電壓位準VSL 時),電晶體操作於截止區(Cutoff),或稱為次臨界區(Sub-threshold),不同的照光強度將會對於電晶體的次臨界電流(Sub-threshold Current)產生電流差異。In the example shown in FIG. 1, the first to fourth photosensitive elements T1 to T4 are described using transistors as an example. For example, a metal oxide semiconductor field effect transistor (MOSFET) or an oxide semiconductor field effect is used. Transistors, such as thin film transistors (TFTs), and NMOS transistors (eg, N-type TFTs) are used as examples in the figure. However, the implementation examples of the first to fourth photosensitive elements T1 to T4 are not limited to this. For example, PMOS transistors, other different types of transistors, or photodiodes can be used. Taking a photodiode as an example, it is usually designed to work in the reverse bias state (Reverse Biased). When a photon with sufficient energy impinges on the diode, it can generate photocurrent, so it can achieve the photosensitive effect. . As shown in Fig. 1, the first photosensitive element to the fourth photosensitive element T1 to T4, the second end of each transistor (for example, the drain, the drain and source of the transistor need to be determined according to the voltage level, here For example), it is connected to the control terminal (for example, the gate) to form a diode connection (Diode Connected), so the operation principle is similar to that of the aforementioned reverse biased photodiode. When the control terminal of the transistor gives a non-conducting control signal (Take NMOS transistor as an example, when the control terminal gives a low logic voltage level V SL ), the transistor operates in the cutoff region, or is called the subcritical region. (Sub-threshold), different light intensity will cause current difference to the sub-threshold current of the transistor.
第一感光元件~第四感光元件T1~T4分別被第一濾光元件~第四濾光元件CF4覆蓋,這些濾光元件可使得第一感光元件~第四感光元件T1~T4針對特定頻率範圍顏色的光進行感測,在第1圖中係使用圓形圖樣標示出這些濾光元件。舉例而言,第一濾光元件CF1可以是藍色濾光片,用以阻隔藍色光以外的光線通過藍色濾光片。當然第一濾光元件CF1並不限定通過藍色光的藍色濾光片,亦可使用其他顏色濾光片。各個濾光元件可通過的光顏色,將於以下多個實施例進一步說明。The first to fourth photosensitive elements T1 to T4 are respectively covered by the first to fourth optical elements CF4 to CF4. These filter elements can make the first to fourth photosensitive elements T1 to T4 target a specific frequency range. Color light is sensed. In Figure 1, these circular filters are used to mark these filter elements. For example, the first filter element CF1 may be a blue filter to block light other than blue light from passing through the blue filter. Of course, the first filter element CF1 is not limited to a blue filter that passes blue light, and other color filters may be used. The color of light that can pass through each filter element will be further described in the following embodiments.
在一實施例中,第一濾光元件CF1用以通過第一色光(以藍光為例),第四濾光元件CF4亦用以通過第一色光,於實作中,第一濾光元件CF1與第四濾光元件CF4可以實體分離,或者第一濾光元件CF1與第四濾光元件CF4可以是一個較大藍色濾光片的部分。在以下的多個實施例亦同,通過相同色光的多個濾光元件,可以是實體分離或者可以是一個濾光片的部分。藉由覆蓋第一濾光元件CF1於第一感光元件T1,第一感光元件T1的第一端與第二端之間的導通程度,係依據第一感光元件T1是否接收到第一色光而改變。In an embodiment, the first filter element CF1 is used to pass the first color light (taking blue light as an example), and the fourth filter element CF4 is also used to pass the first color light. In practice, the first filter The element CF1 and the fourth filter element CF4 may be physically separated, or the first filter element CF1 and the fourth filter element CF4 may be part of a larger blue filter. The same applies to the following embodiments. Multiple filter elements passing the same color light may be physically separated or may be part of a filter. By covering the first filter element CF1 on the first photosensitive element T1, the degree of conduction between the first end and the second end of the first photosensitive element T1 depends on whether the first photosensitive element T1 receives the first color light. change.
電容C1分別電性耦接第一感光元件T1與電壓源,在此例中電壓源係使用高電壓VSH ,此為搭配整體電路設計的操作模式所配置,此處先以放電式(discharging mode)光感測電路舉例說明,因此電壓源配置為高電壓 VSH 。若是使用充電式(charging mode)光感測電路,電壓源可配置為低電壓VSL 。在其他實施方式中,電壓源亦可以是接地電位GND或是像素共用電位VCOM,視電路設計方式而決定。藉由設置電容C1,第一感光元件T1第一端的感測電壓Va能以電荷的形式儲存於電容C1。在以下說明中,對於施加於各感光元件的電壓,將使用高電壓VSH 代表邏輯高位準電壓,以低電壓VSL 代表邏輯低位準電壓,舉例而言,對於供應電壓為1.8V的電路,高電壓VSH 可以是1.8V,低電壓VSL 可以是0V。另外對於取樣電路TSH 的控制信號Gn(t),其電壓位準則分別使用高電壓VGH 以及低電壓VGL 表示。Capacitor C1 is electrically coupled to the first photosensitive element T1 and the voltage source. In this example, the voltage source uses a high voltage V SH . This is configured with the operation mode of the overall circuit design. Here, the discharging mode is used first. ) The light sensing circuit is exemplified, so the voltage source is configured as a high voltage V SH . If a charging mode light sensing circuit is used, the voltage source can be configured as a low voltage V SL . In other embodiments, the voltage source may be a ground potential GND or a pixel common potential VCOM, which is determined according to a circuit design method. By setting the capacitor C1, the sensing voltage Va at the first end of the first photosensitive element T1 can be stored in the capacitor C1 as a charge. In the following description, for the voltage applied to each photosensitive element, a high voltage V SH will be used to represent a logic high level voltage, and a low voltage V SL will be used to represent a logic low level voltage. For example, for a circuit with a supply voltage of 1.8 V, The high voltage V SH may be 1.8V, and the low voltage V SL may be 0V. In addition, for the control signal Gn (t) of the sampling circuit T SH , the voltage bit criterion is expressed by using a high voltage V GH and a low voltage V GL , respectively.
取樣電路TSH 電性耦接於第一感光元件T1的第一端,用以讀取感測電壓Va。在第1圖中以一個電晶體作為取樣電路TSH 的範例,此僅為示例性說明,取樣電路TSH 亦可以是記憶體中的感測放大器(sense amplifier)、類比數位轉換器中的預放大電路(pre-amplifier)、或其他適於連續性或離散性對感測電壓Va進行取樣的電路。The sampling circuit T SH is electrically coupled to the first terminal of the first photosensitive element T1 and used for reading the sensing voltage Va. In FIG. 1, a transistor is used as an example of the sampling circuit T SH . This is only an exemplary illustration. The sampling circuit T SH may also be a sense amplifier in the memory, or a pre-amplifier in an analog-to-digital converter. Amplifying circuit (pre-amplifier), or other circuits suitable for sampling the sensed voltage Va continuously or discretely.
在第1圖的實施例中,第一開關元件TSW1 與第二開關元件TSW2 皆使用NMOS電晶體實作,當然還有其他此發明領域中的通常手段可應用作為開關元件,並不限定於使用NMOS電晶體。由於第一開關元件TSW1 的控制端接收第一控制信號Sn1(t)與第二控制信號Sn2(t)其中之一者,第二開關元件TSW2 的控制端接收第一控制信號Sn1(t)與第二控制信號Sn2(t)其中之另一者,而第三感光元件T3的第二端接收第一控制信號Sn1(t),第四感光元件T4的第二端接收第二控制信號Sn2(t),以此方式連接可以減少電路中所需的控制信號線數量,並能夠達到所需實現的光感測操作,詳細操作過程將於以下說明。In the embodiment of FIG. 1, both the first switching element T SW1 and the second switching element T SW2 are implemented using NMOS transistors. Of course, there are other common methods in the field of the invention that can be applied as the switching element, which is not limited. For the use of NMOS transistors. Since the control terminal of the first switching element T SW1 receives one of the first control signal Sn1 (t) and the second control signal Sn2 (t), the control terminal of the second switching element T SW2 receives the first control signal Sn1 (t ) And the second control signal Sn2 (t), and the second end of the third photosensitive element T3 receives the first control signal Sn1 (t), and the second end of the fourth photosensitive element T4 receives the second control signal Sn2 (t), connected in this way can reduce the number of control signal lines required in the circuit and can achieve the required light sensing operation. The detailed operation process will be described below.
以下詳細說明本發明的各個實施例。第2圖繪示依照本發明第一實施例的光感測電路101示意圖,需說明的是,在所附圖式的第2圖~第25圖,將使用不同框線的圓形來代表通過不同顏色的濾光元件。在第2圖中,第一濾光元件CF1(實線框線)用以通過第一色光(例如藍光)、第二濾光元件CF2(長短線段交錯的虛線框線)用以通過第二色光(例如綠光)、第三濾光元件CF3(實線)用以通過第一色光(藍光)、第四濾光元件CF4(實線)用以通過第一色光(藍光)。光感測電路101為放電式,第一開關元件TSW1 係回應於第二控制信號Sn2(t)選擇性地導通,第二開關元件TSW2 係回應於第一控制信號Sn1(t)選擇性地導通。Hereinafter, various embodiments of the present invention will be described in detail. FIG. 2 is a schematic diagram of the light sensing circuit 101 according to the first embodiment of the present invention. It should be noted that in the second to the twenty-fifth drawings of the drawings, circles with different frame lines will be used to represent the passage. Filter elements of different colors. In Figure 2, the first filter element CF1 (solid line frame) is used to pass the first color light (such as blue light), and the second filter element CF2 (broken line frame with long and short line segments interleaved) is used to pass the second The color light (for example, green light), the third filter element CF3 (solid line) is used to pass the first color light (blue light), and the fourth filter element CF4 (solid line) is used to pass the first color light (blue light). The photo-sensing circuit 101 is a discharge type. The first switching element T SW1 is selectively turned on in response to the second control signal Sn2 (t), and the second switching element T SW2 is selectively turned on in response to the first control signal Sn1 (t). Ground is on.
在另一實施例中,如第3圖繪示依照本發明第一實施例的光感測電路102示意圖。光感測電路102更包括第五感光元件T5,具有第一端及第二端,第五感光元件T5的第二端電性耦接第一感光元件T1的第二端,第五感光元件T5的第一端電性耦接電壓源(此例中為高電壓VSH ),第五感光元件T5被第五濾光元件CF5覆蓋,第五濾光元件CF5(短線段組成的虛線框線)係用以通過第三色光(例如紅光)。光感測電路102亦為放電式,第一開關元件TSW1 係回應於第二控制信號Sn2(t)選擇性地導通,第二開關元件TSW2 係回應於第一控制信號Sn1(t)選擇性地導通。In another embodiment, a schematic diagram of the light sensing circuit 102 according to the first embodiment of the present invention is shown in FIG. 3. The light sensing circuit 102 further includes a fifth photosensitive element T5 having a first end and a second end. The second end of the fifth photosensitive element T5 is electrically coupled to the second end of the first photosensitive element T1 and the fifth photosensitive element T5. The first terminal is electrically coupled to a voltage source (in this example, a high voltage V SH ), the fifth photosensitive element T5 is covered by a fifth filter element CF5, and the fifth filter element CF5 (a dashed frame composed of short line segments) It is used to pass a third color light (such as red light). The light sensing circuit 102 is also a discharge type. The first switching element T SW1 is selectively turned on in response to the second control signal Sn2 (t), and the second switching element T SW2 is selected in response to the first control signal Sn1 (t). By nature.
在第2圖以及第3圖所示的實施例中,藉由設置第二感光元件T2(及第五感光元件T5,其中第五感光元件T5為可選擇性設置),並且使用不同顏色的濾光元件,可使得光感測電路101及光感測電路102能夠有效排除環境光的干擾。此外,藉由設置並聯的第三感光元件T3以及第四感光元件T4,並且使用相同顏色的濾光元件,可以使得第三感光元件T3與第四感光元件T4交替操作,而能夠降低電晶體的工作週期,以避免電晶體因長時間承受汲極-源極電壓而導致的臨界電壓飄移現象,如此能夠提高電路的穩定性與可靠度,延長電路之有效操作時間。以下搭配信號時序圖說明操作流程。In the embodiments shown in FIG. 2 and FIG. 3, by setting a second photosensitive element T2 (and a fifth photosensitive element T5, wherein the fifth photosensitive element T5 is selectively settable), and using filters of different colors The light element enables the light sensing circuit 101 and the light sensing circuit 102 to effectively eliminate the interference of ambient light. In addition, by setting a third photosensitive element T3 and a fourth photosensitive element T4 in parallel, and using a filter element of the same color, the third photosensitive element T3 and the fourth photosensitive element T4 can be operated alternately, and the transistor can be reduced. Working cycle to avoid the critical voltage drift phenomenon caused by the transistor withstanding the drain-source voltage for a long time. This can improve the stability and reliability of the circuit and extend the effective operating time of the circuit. The following describes the operation flow with signal timing diagrams.
第2圖以及第3圖所示電路操作原理類似,皆是屬於放電式光感測電路,以第3圖作為範例說明。以下例子並以第一色光為藍光、第二色光為綠光、第三色光為紅光作為範例,然而本發明並不限於此,第一色光、第二色光、第三色光亦可以是不同的排列方式。第4圖繪示對應於第3圖電路的信號時序圖。光感測電路102交替操作於第一操作模式與一第二操作模式之間,第一操作模式包括第一重置時間區間、第一感測時間區間、及第一取樣時間區間,第二操作模式包括第二重置時間區間、第二感測時間區間、及第二取樣時間區間。The operation principles of the circuits shown in Fig. 2 and Fig. 3 are similar, and both belong to the discharge type photo-sensing circuit, and Fig. 3 is taken as an example for illustration. In the following examples, the first color light is blue light, the second color light is green light, and the third color light is red light. However, the present invention is not limited to this. The first color light, the second color light, and the third color light may also be Different arrangements. FIG. 4 shows a timing diagram of signals corresponding to the circuit of FIG. 3. The light sensing circuit 102 alternately operates between a first operation mode and a second operation mode. The first operation mode includes a first reset time interval, a first sensing time interval, and a first sampling time interval. The second operation The mode includes a second reset time interval, a second sensing time interval, and a second sampling time interval.
第5圖繪示第3圖電路於第一重置時間區間的操作示意圖。於第一重置時間區間,第一控制信號Sn1(t)為高電壓VSH 、第二控制信號Sn2(t)為高電壓VSH ,第一開關元件TSW1 導通,且第二開關元件TSW2 導通,因此電流方向如第5圖箭頭所示,對電容C1充電,使感測電壓Va充電至高重置電位。取樣電路TSH 的控制信號Gn(t)此時為低電壓VGL ,取樣電路TSH 此時為斷開狀態。在圖示中,於電晶體旁邊標示off以代表電晶體操作於截止區,或稱為次臨界區。FIG. 5 is a schematic diagram illustrating the operation of the circuit in FIG. 3 during the first reset time interval. During the first reset time interval, the first control signal Sn1 (t) is a high voltage V SH , the second control signal Sn2 (t) is a high voltage V SH , the first switching element T SW1 is turned on, and the second switching element T SW2 is turned on, so the current direction is as shown by the arrow in FIG. 5. The capacitor C1 is charged to charge the sensing voltage Va to a high reset potential. T SH sampling circuit control signal Gn (t) in this case, the low voltage V GL, the sampling circuit in the OFF state at this time T SH. In the figure, off is marked next to the transistor to indicate that the transistor operates in the cutoff region, or is called a subcritical region.
第6圖繪示第3圖電路於第一感測時間區間的操作示意圖。於第一感測時間區間,第一控制信號Sn1(t)為低電壓VSL 、第二控制信號Sn2(t)為高電壓VSH ,因此第一開關元件TSW1 導通,第二開關元件TSW2 不導通。若此時照射藍光於光感測電路102,則第一感光元件T1及第三感光元件T3會受光激發而產生電流,如第6圖的虛線箭頭所示,如此會使得感測電壓Va下降,例如下降到約等於第一控制信號Sn1(t)的低電壓VSL 。而第二感光元件T2用以感測綠光,第五感光元件T5用以感測紅光,因此當照射藍光於光感測電路102時,第二感光元件T2與第五感光元件T5皆不會產生光電流。另外,由於第二開關元件TSW2 此時為斷開狀態,因此第四感光元件T4亦不會有電流通過。亦即,在第一感測時間區間,第四感光元件T4相當於休息狀態,此時第四感光元件T4的三個端點電壓皆為高電壓VSH ,因此降低了第四感光元件T4所承受的汲極-源極電壓差,能夠減緩第四感光元件T4的臨界電壓飄移現象。FIG. 6 is a schematic diagram illustrating the operation of the circuit in FIG. 3 during the first sensing time interval. During the first sensing time interval, the first control signal Sn1 (t) is a low voltage V SL and the second control signal Sn2 (t) is a high voltage V SH . Therefore, the first switching element T SW1 is turned on and the second switching element T is turned on. SW2 is not conducting. If blue light is irradiated on the light sensing circuit 102 at this time, the first photosensitive element T1 and the third photosensitive element T3 will be excited by light to generate a current, as shown by the dashed arrow in FIG. 6, which will cause the sensing voltage Va to decrease. For example, it drops to a low voltage V SL approximately equal to the first control signal Sn1 (t). The second photosensitive element T2 is used to sense green light, and the fifth photosensitive element T5 is used to sense red light. Therefore, when blue light is irradiated to the light sensing circuit 102, neither the second photosensitive element T2 nor the fifth photosensitive element T5 is used. Photocurrent will be generated. In addition, since the second switching element T SW2 is in an off state at this time, no current will flow through the fourth photosensitive element T4. That is, in the first sensing time interval, the fourth photosensitive element T4 is equivalent to the resting state. At this time, the three terminal voltages of the fourth photosensitive element T4 are all high voltage V SH , so the fourth photosensitive element T4 is reduced. The received drain-source voltage difference can reduce the threshold voltage drift phenomenon of the fourth photosensitive element T4.
而若此時照射白光於光感測電路102,白光為廣頻域分布,即具有各種頻率的顏色成份,因此不僅第一感光元件T1與第三感光元件T3會產生光電流,第二感光元件T2與第五感光元件T5亦會產生光電流。留意第二感光元件T2與第五感光元件T5的第一端係耦接高電壓VSH ,而第一感光元件T1與第三感光元件T3的第二端係耦接低電壓VSL ,因此第二感光元件T2與第五感光元件T5產生的光電流會使得節點電壓Vb上升。經由適當的設計,例如調整電晶體的尺寸或寬度,使得第二感光元件T2與第五感光元件T5的通道寬度大於第一感光元件T1與第三感光元件T3的通道寬度,藉由克希荷夫電流定律分析第一感光元件T1第二端的節點(節點電壓Vb),可以得到在照射白光時,感測電壓Va的電壓值會接近於高電壓VSH ,與照射藍光時感測電壓Va接近低電壓VSL 的情形不同。If white light is irradiated to the light sensing circuit 102 at this time, the white light is distributed in a wide frequency range, that is, it has color components of various frequencies. Therefore, not only the first photosensitive element T1 and the third photosensitive element T3 may generate a photocurrent, but the second photosensitive element T2 and the fifth photosensitive element T5 also generate photocurrent. Note that the first ends of the second photosensitive element T2 and the fifth photosensitive element T5 are coupled to the high voltage V SH , and the second ends of the first photosensitive element T1 and the second photosensitive element T3 are coupled to the low voltage V SL . Therefore, the first The photocurrent generated by the two photosensitive elements T2 and the fifth photosensitive element T5 causes the node voltage Vb to rise. Through appropriate design, such as adjusting the size or width of the transistor, the channel width of the second photosensitive element T2 and the fifth photosensitive element T5 is larger than the channel width of the first photosensitive element T1 and the third photosensitive element T3. Analysis of the node (node voltage Vb) at the second end of the first photoreceptor element T1 by the husband's current law, it can be obtained that when the white light is irradiated, the voltage value of the sensing voltage Va will be close to the high voltage V SH and close to the sensed voltage Va when the blue light is illuminated The situation for low voltage V SL is different.
換句話說,在上述實施例中,感測電壓Va對應於藍光的電壓值與對應於白光或多色光的電壓值不同。經由適當的設計,只有當藍光光通量相對於綠光(若僅使用第二感光元件T2)與紅光(若使用第二感光元件T2以及第五感光元件T5)光通量的比值大於一個門檻值時,感測電壓Va才會在第一感測時間區間被拉低到低電壓VSL 。此門檻值例如是2,門檻值可視應用與設計需求調整,可藉由改變電晶體的尺寸調整門檻值。由上述的設計,實現了對環境光不敏感的光感測電路。In other words, in the embodiment described above, the voltage value of the sensed voltage Va corresponding to blue light is different from the voltage value of white light or polychromatic light. With proper design, only when the ratio of the blue light flux to the green light (if only the second photosensitive element T2 is used) and the red light (if the second photosensitive element T2 and the fifth photosensitive element T5 are used) is greater than a threshold value, Only the sensing voltage Va is pulled down to the low voltage V SL in the first sensing time interval. The threshold value is, for example, 2. The threshold value can be adjusted according to application and design requirements. The threshold value can be adjusted by changing the size of the transistor. With the above design, a light sensing circuit that is insensitive to ambient light is implemented.
第7圖繪示第3圖電路於第一取樣時間區間的操作示意圖。於第一取樣時間區間中,第一控制信號Sn1(t)為低電壓VSL 、第二控制信號Sn2(t)為高電壓VSH ,與第一感測時間區間相同,第一開關元件TSW1 導通,且該第二開關元件TSW2 不導通。取樣電路TSH 的控制信號Gn(t)此時為高電壓VGH ,可將感測電壓Va輸出至輸出節點OUT,取樣電路TSH 用以取得第一感光元件T1第一端的電壓。輸出節點OUT可耦接一個讀取電路(Readout Circuit),以讀取感測結果。FIG. 7 is a schematic diagram illustrating the operation of the circuit in FIG. 3 during the first sampling time interval. In the first sampling time interval, the first control signal Sn1 (t) is a low voltage V SL and the second control signal Sn2 (t) is a high voltage V SH , which is the same as the first sensing time interval. The first switching element T SW1 is turned on, and the second switching element T SW2 is not turned on. The control signal Gn (t) of the sampling circuit T SH is now a high voltage V GH , and the sensing voltage Va can be output to the output node OUT. The sampling circuit T SH is used to obtain the voltage of the first end of the first photosensitive element T1. The output node OUT can be coupled to a readout circuit to read the sensing result.
第二重置時間區間與第一重置時間區間的操作相同,對電容C1充電,使得感測電壓Va充電至高重置電位,於此不再重複贅述。第8圖繪示第3圖電路於第二感測時間區間的操作示意圖。於第二感測時間區間中,第一控制信號Sn1(t)為高電壓VSH 、第二控制信號Sn2(t)為低電壓VSL ,第一開關元件TSW1 不導通,第二開關元件TSW2 導通。若此時照射藍光於光感測電路102,則第一感光元件T1及第四感光元件T4會受光激發而產生電流,如第8圖的虛線箭頭所示,如此會使得感測電壓Va下降。若此時照射白光於光感測電路102,第二感光元件T2與第五感光元件T5亦會產生光電流。經由適當設計,可使得感測電壓Va對應於藍光的電壓值與對應於白光或多色光的電壓值不同,此處不再重複贅述。The operation of the second reset time interval is the same as that of the first reset time interval, and the capacitor C1 is charged, so that the sensing voltage Va is charged to a high reset potential, which is not repeated here. FIG. 8 is a schematic diagram illustrating the operation of the circuit in FIG. 3 during the second sensing time interval. In the second sensing time interval, the first control signal Sn1 (t) is a high voltage V SH , the second control signal Sn2 (t) is a low voltage V SL , the first switching element T SW1 is not turned on, and the second switching element T SW2 is turned on. If blue light is irradiated to the light sensing circuit 102 at this time, the first photosensitive element T1 and the fourth photosensitive element T4 will be excited by light to generate a current, as shown by the dotted arrow in FIG. 8, which will cause the sensing voltage Va to drop. If white light is irradiated to the light sensing circuit 102 at this time, the second photosensitive element T2 and the fifth photosensitive element T5 also generate a photocurrent. Through proper design, the voltage value of the sensing voltage Va corresponding to the blue light is different from the voltage value corresponding to the white light or the multi-color light, which is not repeated here.
在第二感測時間區間中,第三感光元件T3為休息狀態,第三感光元件T3的三個端點電壓皆為高電壓VSH ,降低了第三感光元件T3所承受的汲極-源極電壓差。亦即,在此實施例中,於第一操作模式與第二操作模式中,第三感光元件T3與第四感光元件T4係輪流交替工作,可避免電晶體長時間操作,而能夠改善臨界電壓飄移現象。In the second sensing time interval, the third photosensitive element T3 is in a resting state, and the three terminal voltages of the third photosensitive element T3 are all high voltage V SH , which reduces the drain-source endured by the third photosensitive element T3. Extreme voltage difference. That is, in this embodiment, in the first operation mode and the second operation mode, the third photosensitive element T3 and the fourth photosensitive element T4 work alternately in turn, which can prevent the transistor from operating for a long time and can improve the threshold voltage. Drift phenomenon.
第9圖繪示第3圖電路於第二取樣時間區間的操作示意圖。於第二取樣時間區間中,第一開關元件TSW1 不導通,第二開關元件TSW2 導通,取樣電路TSH 的控制信號Gn(t)此時為高電壓VGH ,可將感測電壓Va輸出至輸出節點OUT,操作類於似第一取樣時間。FIG. 9 illustrates the operation of the circuit of FIG. 3 in the second sampling time interval. In the second sampling time interval, the first switching element T SW1 is not turned on and the second switching element T SW2 is turned on. The control signal Gn (t) of the sampling circuit T SH is now a high voltage V GH , and the sensing voltage Va can be changed. Output to the output node OUT, the operation is similar to the first sampling time.
第2圖及第3圖所繪示為放電式光感測電路,以下更說明充電式光感測電路實施例,第10圖繪示依照本發明第一實施例的光感測電路103示意圖。光感測電路103與第3圖所示的光感測電路102架構類似,第五感光元件T5亦為可選擇性設置。差異點說明如下:於充電式光感測電路103,電容C1耦接的電壓源是低電壓VSL ,第二感光元件T2(及第五感光元件T5)耦接的電壓源是低電壓VSL 。第一開關元件TSW1 回應於第一控制信號Sn1(t)選擇性地導通,第二開關元件TSW2 回應於第二控制信號Sn2(t)選擇性地導通。第二感光元件T2(及第五感光元件T5)更具有一控制端,用以接收重置切換信號SW(t)。Figures 2 and 3 show discharge-type photo-sensing circuits. An embodiment of a charge-type photo-sensing circuit is described below. Figure 10 shows a schematic diagram of a photo-sensing circuit 103 according to the first embodiment of the present invention. The photo-sensing circuit 103 is similar in structure to the photo-sensing circuit 102 shown in FIG. 3, and the fifth photo-sensing element T5 is also selectively disposed. The differences are explained as follows: In the rechargeable light sensing circuit 103, the voltage source coupled to the capacitor C1 is a low voltage V SL , and the voltage source coupled to the second photosensitive element T2 (and the fifth photosensitive element T5) is a low voltage V SL . The first switching element T SW1 is selectively turned on in response to the first control signal Sn1 (t), and the second switching element T SW2 is selectively turned on in response to the second control signal Sn2 (t). The second photosensitive element T2 (and the fifth photosensitive element T5) further has a control terminal for receiving the reset switching signal SW (t).
第10圖所示為一種充電式光感測電路的實施例,其中第二感光元件T2的控制端直接由外部給予重置切換信號SW(t),此為一種實作方式。在另一實施例中,第二感光元件T2亦可連接為二極體連接形式,將第二感光元件T2的控制端連接至低電壓VSL ,如此亦可以實現充電式光感測電路。在充電式光感測電路102當中,第一感光元件T1、第三感光元件T3、第四感光元件T4為二極體連接形式,由於在感測階段是要對電容C1充電,因此二極體的陽極在圖中的上端、陰極在下端,以配置為逆向偏壓狀態。充電式光感測電路107當中的第一感光元件T1、第三感光元件T3、第四感光元件T4的連接形式與第3圖所示放電式光感測電路102不同。FIG. 10 shows an embodiment of a rechargeable light sensing circuit, in which the control terminal of the second photosensitive element T2 directly gives a reset switching signal SW (t) from the outside, which is an implementation method. In another embodiment, the second photosensitive element T2 may also be connected in a diode connection form, and the control terminal of the second photosensitive element T2 is connected to a low voltage V SL , so that a rechargeable light sensing circuit can also be implemented. In the rechargeable light sensing circuit 102, the first photosensitive element T1, the third photosensitive element T3, and the fourth photosensitive element T4 are diode-connected. Since the capacitor C1 is charged in the sensing stage, the diode The anode is at the upper end in the figure and the cathode is at the lower end to be configured in a reverse bias state. The connection type of the first photosensitive element T1, the third photosensitive element T3, and the fourth photosensitive element T4 in the rechargeable light sensing circuit 107 is different from that of the discharge type light sensing circuit 102 shown in FIG.
第11圖繪示對應於第10圖電路的信號時序圖,光感測電路103交替操作於第一操作模式與一第二操作模式之間,第一操作模式包括第一重置時間區間、第一感測時間區間、及第一取樣時間區間,第二操作模式包括第二重置時間區間、第二感測時間區間、及第二取樣時間區間。FIG. 11 shows a signal timing diagram corresponding to the circuit of FIG. 10. The light sensing circuit 103 operates alternately between a first operation mode and a second operation mode. The first operation mode includes a first reset time interval, a first A sensing time interval and a first sampling time interval. The second operation mode includes a second reset time interval, a second sensing time interval, and a second sampling time interval.
第12圖繪示第11圖電路於第一重置時間區間的操作示意圖。於第一重置時間區間中,第一控制信號Sn1(t)為低電壓VSL 、第二控制信號Sn2(t)為低電壓VSL ,第一開關元件TSW1 不導通,第二開關元件TSW2 不導通。重置切換信號SW(t)為高電壓VSH ,第二感光元件T2(及第五感光元件T5)受重置切換信號SW(t)控制而導通,因此如第12圖箭頭所示,對電容C1放電,使圖中感測電壓Va放電至低重置電位。第二重置時間區間的操作與第一重置時間區間相同,因此不再重複贅述。FIG. 12 is a schematic diagram illustrating the operation of the circuit in FIG. 11 during the first reset time interval. In the first reset time interval, the first control signal Sn1 (t) is a low voltage V SL , the second control signal Sn2 (t) is a low voltage V SL , the first switching element T SW1 is not turned on, and the second switching element T SW2 is not conducting. The reset switching signal SW (t) is a high voltage V SH , and the second photosensitive element T2 (and the fifth photosensitive element T5) is controlled by the reset switching signal SW (t) to be turned on. Therefore, as shown by the arrow in FIG. The capacitor C1 is discharged, so that the sensing voltage Va in the figure is discharged to a low reset potential. The operation of the second reset time interval is the same as that of the first reset time interval, and therefore will not be described repeatedly.
於第一感測時間區間,電壓源的電壓位準被提供至重置切換信號SW(t),因此重置切換信號SW(t)為低電壓VSL ,使得第二感光元件T2(及第五感光元件T5)操作於次臨界區。此時第二感光元件T2的第一端與第二端之間的導通程度,係依據第二感光元件T2是否接收到綠光而改變。第一控制信號Sn1(t)為高電壓VSH 、第二控制信號Sn2(t)為低電壓VSL ,因此第一開關元件TSW1 導通,第二開關元件TSW2 不導通。若此時照射藍光於光感測電路103,則第一感光元件T1及第三感光元件T3會受光激發而產生電流,電流方向從第一控制信號Sn1(t)的高電壓VSH 流向電容C1,如此會使得感測電壓Va上升,例如上升到約等於第一控制信號Sn1(t)的高電壓VSH 。在第一感測時間區間,第四感光元件T4相當於休息狀態。若照射白光於光感測電路103,不僅第一感光元件T1與第三感光元件T3會產生光電流,第二感光元件T2(及第五感光元件T5)亦會產生光電流,第二感光元件T2(及第五感光元件T5)產生的光電流會降低節點電壓Vb。經由適當的設計,可使得感測電壓Va對應於藍光的電壓值與對應於白光或多色光的電壓值不同。During the first sensing time interval, the voltage level of the voltage source is provided to the reset switching signal SW (t), so the reset switching signal SW (t) is a low voltage V SL , so that the second photosensitive element T2 (and the The five photosensitive elements T5) operate in a subcritical region. At this time, the degree of conduction between the first end and the second end of the second photosensitive element T2 is changed according to whether the second photosensitive element T2 receives green light. Since the first control signal Sn1 (t) is a high voltage V SH and the second control signal Sn2 (t) is a low voltage V SL , the first switching element T SW1 is turned on and the second switching element T SW2 is not turned on. If blue light is irradiated to the light sensing circuit 103 at this time, the first photosensitive element T1 and the third photosensitive element T3 will be excited by light to generate a current, and the current direction flows from the high voltage V SH of the first control signal Sn1 (t) to the capacitor C1. In this way, the sensing voltage Va increases, for example, to a high voltage V SH approximately equal to the first control signal Sn1 (t). In the first sensing time interval, the fourth photosensitive element T4 corresponds to a resting state. If white light is irradiated to the light sensing circuit 103, not only the first photosensitive element T1 and the third photosensitive element T3 will generate a photocurrent, but the second photosensitive element T2 (and the fifth photosensitive element T5) will also generate a photocurrent, and the second photosensitive element The photocurrent generated by T2 (and the fifth photosensitive element T5) reduces the node voltage Vb. Through proper design, the voltage value of the sensing voltage Va corresponding to the blue light and the voltage value corresponding to the white light or the polychromatic light can be made different.
於第二感測時間區間,第一控制信號Sn1(t)為低電壓VSL 、第二控制信號Sn2(t)為高電壓VSH ,因此第一開關元件TSW1 不導通,第二開關元件TSW2 導通。在第二感測時間區間,第三感光元件T3相當於休息狀態。於第一取樣時間區間及第二取樣時間區間中,取樣電路TSH 的控制信號Gn(t)為高電壓VGH ,取樣電路TSH 用以取得第一感光元件T1第一端的電壓。During the second sensing time interval, the first control signal Sn1 (t) is a low voltage V SL and the second control signal Sn2 (t) is a high voltage V SH . Therefore, the first switching element T SW1 is not turned on, and the second switching element T SW2 is turned on. In the second sensing time interval, the third photosensitive element T3 corresponds to a resting state. A first sampling time interval and the second sampling time interval, T SH sampling circuit control signal Gn (t) of the high voltage V GH, T SH sampling circuit for obtaining a first voltage of the first terminal T1 of the photosensitive member.
根據上述第2圖~第12圖所繪示多個實施例的光感測電路,不論是放電式或充電式光感測電路,可藉由使用兩個搭配相同顏色濾光元件的感光元件,在第一操作模式以及第二操作模式交替輪流使用,而能夠增加電路在長時間操作之穩定性與可靠度,達到延長電路之有效操作時間。並且由於開關元件的控制信號電性耦接至感光元件的一端,能夠共用控制信號,如此可以節省電路中所需的繞線面積,降低設計複雜度並且提升產品良率,尤其當面臨大面板尺寸時,更能顯著地降低硬體成本與電路面積,並能夠提升畫素之開口率。According to the light sensing circuits of the multiple embodiments shown in Figs. 2 to 12 above, whether it is a discharge type or a charge type light sensing circuit, two photosensitive elements with the same color filter element can be used. Used alternately in the first operation mode and the second operation mode, which can increase the stability and reliability of the circuit in a long time operation, and extend the effective operation time of the circuit. And because the control signal of the switching element is electrically coupled to one end of the photosensitive element, the control signal can be shared, which can save the winding area required in the circuit, reduce the design complexity and improve the product yield, especially when facing large panel sizes Time, it can significantly reduce the hardware cost and circuit area, and can improve the pixel opening rate.
以下說明本發明的另一應用實施例,第13圖繪示依照本發明第一實施例的光感測電路104示意圖。在第13圖中,第一濾光元件CF1用以通過第一色光(例如藍光)、第二濾光元件CF2(長短線段交錯的虛線框線)用以通過第二色光(例如綠光)、第三濾光元件CF3(短線段組成的虛線框線)用以通過第三色光(例如紅光)、第四濾光元件CF4(實線)用以通過第一色光(藍光)。光感測電路104為放電式,第一開關元件TSW1 係回應於第二控制信號Sn2(t)選擇性地導通,第二開關元件TSW2 係回應於第一控制信號Sn1(t)選擇性地導通。The following describes another application embodiment of the present invention. FIG. 13 shows a schematic diagram of the light sensing circuit 104 according to the first embodiment of the present invention. In Fig. 13, the first filter element CF1 is used to pass the first color light (for example, blue light), and the second filter element CF2 (the dashed line frame with the long and short line segments interleaved) is used to pass the second color light (for example, green light) The third filter element CF3 (a dashed frame line composed of short line segments) is used to pass a third color light (for example, red light), and the fourth filter element CF4 (solid line) is used to pass a first color light (blue light). The light sensing circuit 104 is a discharge type. The first switching element T SW1 is selectively turned on in response to the second control signal Sn2 (t), and the second switching element T SW2 is selectively turned on in response to the first control signal Sn1 (t). Ground is on.
在另一實施例中,第14圖繪示依照本發明第一實施例的光感測電路105示意圖。光感測電路105更包括第五感光元件T5,具有第一端及第二端,第五感光元件T5的第二端電性耦接第四感光元件T4的第一端,第五感光元件T5的第一端電性耦接電壓源(此例中為高電壓VSH ),第五感光元件T5被第五濾光元件CF5覆蓋,第五濾光元件CF5(短線段組成的虛線框線)係用以通過第三色光(紅光)。光感測電路105亦為放電式,第一開關元件TSW1 係回應於第二控制信號Sn2(t)選擇性地導通,第二開關元件TSW2 係回應於第一控制信號Sn1(t)選擇性地導通。In another embodiment, FIG. 14 is a schematic diagram of the light sensing circuit 105 according to the first embodiment of the present invention. The light sensing circuit 105 further includes a fifth photosensitive element T5 having a first end and a second end. The second end of the fifth photosensitive element T5 is electrically coupled to the first end of the fourth photosensitive element T4 and the fifth photosensitive element T5. The first terminal is electrically coupled to a voltage source (in this example, a high voltage V SH ), the fifth photosensitive element T5 is covered by a fifth filter element CF5, and the fifth filter element CF5 (a dashed frame composed of short line segments) It is used to pass the third color light (red light). The light sensing circuit 105 is also a discharge type. The first switching element T SW1 is selectively turned on in response to the second control signal Sn2 (t), and the second switching element T SW2 is selected in response to the first control signal Sn1 (t). By nature.
在第13圖以及第14圖所示的實施例中,藉由設置第二感光元件T2(及第五感光元件T5,其中第五感光元件T5為可選擇性設置),並且使用不同顏色的濾光元件,可使得光感測電路104及光感測電路105能夠有效排除環境光的干擾。此外,藉由設置並聯的第三感光元件T3以及第四感光元件T4,並且使用不同顏色的濾光元件,例如第三濾光元件CF3通過紅光,第四濾光元件CF4通過藍光,可以將感測兩種不同色光整合於同一畫素之光感測電路,使得電路可以偵測出更多不同顏色之光源輸入。同時因為不同色光的感測可整合,使得感測電路的間距能夠縮小,能夠提升畫素之解析度。以下搭配信號時序圖說明操作流程。In the embodiments shown in FIG. 13 and FIG. 14, by setting a second photosensitive element T2 (and a fifth photosensitive element T5, where the fifth photosensitive element T5 is selectively settable), and using filters of different colors The light element enables the light sensing circuit 104 and the light sensing circuit 105 to effectively eliminate the interference of ambient light. In addition, by setting a third photosensitive element T3 and a fourth photosensitive element T4 in parallel, and using different color filter elements, for example, the third filter element CF3 passes red light, and the fourth filter element CF4 passes blue light. A light sensing circuit that senses two different colors of light integrated into the same pixel, so that the circuit can detect more light source inputs of different colors. At the same time, because the sensing of different colored lights can be integrated, the spacing of the sensing circuits can be reduced, and the resolution of the pixels can be improved. The following describes the operation flow with signal timing diagrams.
第13圖以及第14圖所示電路操作原理類似,皆是屬於放電式光感測電路,以第14圖作為範例說明。以下例子並以第一色光為藍光、第二色光為綠光、第三色光為紅光作為範例,然而本發明並不限於此,第一色光、第二色光、第三色光亦可以是不同的排列方式。第15圖繪示對應於第14圖電路的信號時序圖。光感測電路105交替操作於第一操作模式與一第二操作模式之間,第一操作模式包括第一重置時間區間、第一感測時間區間、及第一取樣時間區間,第二操作模式包括第二重置時間區間、第二感測時間區間、及第二取樣時間區間。The operating principles of the circuits shown in FIG. 13 and FIG. 14 are similar, and both belong to the discharge-type light sensing circuit. The illustration in FIG. 14 is taken as an example. In the following examples, the first color light is blue light, the second color light is green light, and the third color light is red light. However, the present invention is not limited to this. The first color light, the second color light, and the third color light may also be Different arrangements. FIG. 15 shows a signal timing diagram corresponding to the circuit of FIG. 14. The light sensing circuit 105 operates alternately between a first operation mode and a second operation mode. The first operation mode includes a first reset time interval, a first sensing time interval, and a first sampling time interval. The second operation The mode includes a second reset time interval, a second sensing time interval, and a second sampling time interval.
第16圖繪示第14圖電路於第一重置時間區間的操作示意圖。於第一重置時間區間,第一控制信號Sn1(t)為高電壓VSH 、第二控制信號Sn2(t)為高電壓VSH ,第一開關元件TSW1 導通,且第二開關元件TSW2 導通,因此如第16圖箭頭所示,對電容C1充電,使感測電壓Va充電至高重置電位。取樣電路TSH 的控制信號Gn(t)此時為低電壓VGL ,取樣電路TSH 此時為斷開狀態。FIG. 16 is a schematic diagram illustrating the operation of the circuit in FIG. 14 during the first reset time interval. During the first reset time interval, the first control signal Sn1 (t) is a high voltage V SH , the second control signal Sn2 (t) is a high voltage V SH , the first switching element T SW1 is turned on, and the second switching element T SW2 is turned on, so as shown by the arrow in FIG. 16, the capacitor C1 is charged to charge the sensing voltage Va to a high reset potential. T SH sampling circuit control signal Gn (t) in this case, the low voltage V GL, the sampling circuit in the OFF state at this time T SH.
第17圖繪示第14圖電路於第一感測時間區間的操作示意圖。於第一感測時間區間,第一控制信號Sn1(t)為低電壓VSL 、第二控制信號Sn2(t)為高電壓VSH ,因此第一開關元件TSW1 導通,第二開關元件TSW2 不導通。留意第17圖中繪示的虛線箭頭(從電容C1指向第三感光元件T3),此電流路徑通過串聯的第一感光元件T1(感測藍光)以及第三感光元件T3(感測紅光)。因此,在第一感測時間區間,光感測電路105需同時接收到藍光以及紅光(例如紫光)足夠的強度,才能夠建立如虛線箭頭所示的電流路徑,使得感測電壓Va下降,例如下降到約等於第一控制信號Sn1(t)的低電壓VSL 。FIG. 17 is a schematic diagram illustrating the operation of the circuit of FIG. 14 in the first sensing time interval. During the first sensing time interval, the first control signal Sn1 (t) is a low voltage V SL and the second control signal Sn2 (t) is a high voltage V SH . Therefore, the first switching element T SW1 is turned on and the second switching element T is turned on. SW2 is not conducting. Pay attention to the dotted arrow shown in Figure 17 (from the capacitor C1 to the third photosensitive element T3). This current path passes through the first photosensitive element T1 (sensing blue light) and the third photosensitive element T3 (sensing red light) in series. . Therefore, in the first sensing time interval, the light sensing circuit 105 needs to simultaneously receive sufficient intensity of blue light and red light (for example, purple light) to be able to establish a current path shown by a dotted arrow, so that the sensing voltage Va decreases. For example, it drops to a low voltage V SL approximately equal to the first control signal Sn1 (t).
在第一感測時間區間,由於第二開關元件TSW2 不導通,因此節點電壓Vb不受到第五感光元件T5的影響。而第二感光元件T2用以感測綠光,當照射藍光及紅光於光感測電路105時,第二感光元件T2不會產生光電流。倘若是照射白光於光感測電路105,則不僅第一感光元件T1與第三感光元件T3會產生光電流,第二感光元件T2亦會產生光電流。由於第二感光元件T2的第一端耦接高電壓VSH ,第二感光元件T2所產生的光電流將會提高節點電壓Vb。經由適當的設計,例如調整電晶體的尺寸或寬度,可以使得感測電壓Va對應於紫光(第一感光元件T1及第三感光元件T3皆產生光電流)的電壓值與對應於白光的電壓值不同,如此即可實現對環境光不敏感的光感測電路。In the first sensing time interval, since the second switching element T SW2 is not turned on, the node voltage Vb is not affected by the fifth photosensitive element T5. The second photosensitive element T2 is used to sense green light. When blue light and red light are irradiated to the light sensing circuit 105, the second photosensitive element T2 does not generate a photocurrent. If white light is irradiated to the light sensing circuit 105, not only the first photosensitive element T1 and the third photosensitive element T3 will generate a photocurrent, but also the second photosensitive element T2 will generate a photocurrent. Since the first terminal of the second photosensitive element T2 is coupled to the high voltage V SH , the photocurrent generated by the second photosensitive element T2 will increase the node voltage Vb. Through proper design, such as adjusting the size or width of the transistor, the sensing voltage Va can correspond to the voltage value of the purple light (the first photosensitive element T1 and the third photosensitive element T3 both generate a photocurrent) and the voltage value corresponding to the white light. Unlike this, a light sensing circuit that is insensitive to ambient light can be implemented in this way.
第18圖繪示第14圖電路於第一取樣時間區間的操作示意圖。於第一取樣時間區間中,第一控制信號Sn1(t)為低電壓VSL 、第二控制信號Sn2(t)為高電壓VSH ,與第一感測時間區間相同,第一開關元件TSW1 導通,且該第二開關元件TSW2不導通。取樣電路TSH 的控制信號Gn(t)此時為高電壓VGH ,可將感測電壓Va輸出至輸出節點OUT,取樣電路TSH 用以取得第一感光元件T1第一端的電壓。輸出節點OUT可耦接一個讀取電路。FIG. 18 illustrates the operation of the circuit of FIG. 14 in the first sampling time interval. In the first sampling time interval, the first control signal Sn1 (t) is a low voltage V SL and the second control signal Sn2 (t) is a high voltage V SH , which is the same as the first sensing time interval. The first switching element T SW1 is turned on, and the second switching element TSW2 is not turned on. The control signal Gn (t) of the sampling circuit T SH is now a high voltage V GH , and the sensing voltage Va can be output to the output node OUT. The sampling circuit T SH is used to obtain the voltage of the first end of the first photosensitive element T1. The output node OUT can be coupled to a read circuit.
第二重置時間區間與第一重置時間區間的操作相同,對電容C1充電,使得感測電壓Va充電至高重置電位,於此不再重複贅述。第19圖繪示第14圖電路於第二感測時間區間的操作示意圖。於第二感測時間區間中,第一控制信號Sn1(t)為高電壓VSH 、第二控制信號Sn2(t)為低電壓VSL ,第一開關元件TSW1 不導通,第二開關元件TSW2 導通。若此時照射藍光於光感測電路105,則第一感光元件T1及第四感光元件T4會受光激發而產生電流,如第19圖的虛線箭頭(從電容C1指向第四感光元件T4)所示,如此會使得感測電壓Va下降。若此時照射白光於光感測電路105,則第二感光元件T2(感應綠光)及第五感光元件T5(感應紅光)亦會產生光電流。由於第二感光元件T2(及第五感光元件T5)的第一端耦接高電壓VSH ,第二感光元件T2(及第五感光元件T5)所產生的光電流將會提高節點電壓Vb。經由適當設計,可使得感測電壓Va對應於藍光的電壓值與對應於白光或多色光的電壓值不同,此處不再重複贅述。The operation of the second reset time interval is the same as that of the first reset time interval, and the capacitor C1 is charged, so that the sensing voltage Va is charged to a high reset potential, which is not repeated here. FIG. 19 is a schematic diagram illustrating the operation of the circuit of FIG. 14 in the second sensing time interval. In the second sensing time interval, the first control signal Sn1 (t) is a high voltage V SH , the second control signal Sn2 (t) is a low voltage V SL , the first switching element T SW1 is not turned on, and the second switching element T SW2 is turned on. If blue light is irradiated to the light sensing circuit 105 at this time, the first photosensitive element T1 and the fourth photosensitive element T4 will be excited by light to generate a current, as shown by the dotted arrow in FIG. 19 (from the capacitor C1 to the fourth photosensitive element T4) It is shown that this will cause the sensing voltage Va to decrease. If white light is irradiated to the light sensing circuit 105 at this time, the second photosensitive element T2 (inductive green light) and the fifth photosensitive element T5 (inductive red light) also generate photocurrent. Since the first end of the second photosensitive element T2 (and the fifth photosensitive element T5) is coupled to the high voltage V SH , the photocurrent generated by the second photosensitive element T2 (and the fifth photosensitive element T5) will increase the node voltage Vb. Through proper design, the voltage value of the sensing voltage Va corresponding to the blue light is different from the voltage value corresponding to the white light or the multi-color light, which is not repeated here.
第20圖繪示第14圖電路於第二取樣時間區間的操作示意圖。於第二取樣時間區間中,第一開關元件TSW1 不導通,第二開關元件TSW2 導通,取樣電路TSH 的控制信號Gn(t)此時為高電壓VGH ,可將感測電壓Va輸出至輸出節點OUT,操作類於似第一取樣時間。FIG. 20 shows the operation of the circuit of FIG. 14 in the second sampling time interval. In the second sampling time interval, the first switching element T SW1 is not turned on and the second switching element T SW2 is turned on. The control signal Gn (t) of the sampling circuit T SH is now a high voltage V GH , and the sensing voltage Va can be changed. Output to the output node OUT, the operation is similar to the first sampling time.
如上所述實施例的光感測電路104以及光感測電路105,在第一操作模式感測紫光(紅光與藍光的混合光),在第二操作模式感測藍光,如此能夠將兩種不同色光的感測整合於同一電路,降低了光感測電路的面積,因此能夠縮小多個光感測電路之間的間距,提升畫素解析度。同時,由於開關元件與感光元件共用控制信號,降低所需信號線數量,能夠提升畫素之開口率。The light sensing circuit 104 and the light sensing circuit 105 of the embodiment described above sense purple light (mixed light of red light and blue light) in the first operation mode and blue light in the second operation mode. The sensing of different colors of light is integrated in the same circuit, which reduces the area of the light sensing circuit, so the distance between multiple light sensing circuits can be reduced, and the pixel resolution can be improved. At the same time, because the switching element and the light sensing element share the control signal, the number of required signal lines is reduced, and the aperture ratio of the pixel can be improved.
第21圖繪示依照本發明第一實施例的光感測電路106示意圖。在此實施例中,光感測電路106更包括第六感光元件T6,具有第一端及第二端,第六感光元件T6的第一端電性耦接第一感光元件T1的第一端,第六感光元件T6的第二端電性耦接第一感光元件T1的第二端,即第六感光元件T6並聯於第一感光元件T1。第六感光元件T6被第六濾光元件CF6覆蓋,第六濾光元件CF6係用以通過第三色光(紅光)。第21圖所示實施例中,第一濾光元件CF1及第四濾光元件CF4用以過過第一色光(藍光),第二濾光元件CF2用以通過第二色光(綠光),第三濾光元件CF3及第六濾光元件CF6用以過過第三色光(紅光)。FIG. 21 is a schematic diagram of a light sensing circuit 106 according to the first embodiment of the present invention. In this embodiment, the light sensing circuit 106 further includes a sixth photosensitive element T6, which has a first end and a second end. The first end of the sixth photosensitive element T6 is electrically coupled to the first end of the first photosensitive element T1. The second end of the sixth photosensitive element T6 is electrically coupled to the second end of the first photosensitive element T1, that is, the sixth photosensitive element T6 is connected in parallel to the first photosensitive element T1. The sixth photosensitive element T6 is covered by a sixth filter element CF6, and the sixth filter element CF6 is used to pass the third color light (red light). In the embodiment shown in FIG. 21, the first filter element CF1 and the fourth filter element CF4 are used to pass the first color light (blue light), and the second filter element CF2 is used to pass the second color light (green light). The third filter element CF3 and the sixth filter element CF6 are used to pass the third color light (red light).
光感測電路106的操作原理類似於光感測電路104及光感測電路105,各個時間區間的詳細操作不再重複贅述。藉由第一感光元件T1及第六感光元件T6並聯,不論照射藍光或紅光於光感測電路時,第一感光元件T1及第六感光元件T6其中至少一個會產生光電流。而藉由第一開關元件TSW1 與第二開關元件TSW2 交替開關切換,可以在第一操作模式感測紅光,在第二操作模式感測藍光。The operation principle of the photo-sensing circuit 106 is similar to that of the photo-sensing circuit 104 and the photo-sensing circuit 105, and detailed operations in each time interval will not be repeated. By connecting the first photosensitive element T1 and the sixth photosensitive element T6 in parallel, at least one of the first photosensitive element T1 and the sixth photosensitive element T6 generates a photocurrent when blue light or red light is irradiated to the light sensing circuit. By alternately switching the first switching element T SW1 and the second switching element T SW2 , red light can be sensed in the first operation mode and blue light can be sensed in the second operation mode.
如第13圖、第14圖、第21圖所示的光感測電路,能夠將兩種色光的感測整合於同一電路,且兩種色光可以是光的三原色,亦可以是三原色的混色。舉例而言,同一電路的兩種色光可以是選自紅色光、藍色光、綠色光、紫色光(紅色光與藍色光的混合光)、黃色光(紅色光及綠色光的混合光)、青色光(藍色光與綠色光的混合光)。光感測電路可應用於偵測光筆輸入,由於具備有六種顏色,因此光筆可以有六種色彩輸入,皆可以成功讀取,並且由於可將兩種顏色的感測器整合在一個畫素電路,縮小了光感測電路之間的距離,更能夠提高成功取樣光筆輸入資料的機會。The light sensing circuits shown in FIG. 13, FIG. 14, and FIG. 21 can integrate the sensing of two kinds of color light in the same circuit, and the two kinds of color light can be three primary colors of light or a mixed color of three primary colors. For example, the two colored lights of the same circuit can be selected from red light, blue light, green light, purple light (mixed light of red light and blue light), yellow light (mixed light of red light and green light), and cyan. Light (mixed light of blue light and green light). The light sensing circuit can be used to detect the light pen input. Because it has six colors, the light pen can have six color inputs, all of which can be successfully read, and because the two color sensors can be integrated into one pixel Circuit, which reduces the distance between the light sensing circuits and improves the chance of successfully sampling the light pen input data.
第22圖繪示依照本發明第一實施例的光感測電路與像素配置示意圖。在一實施例中,顯示面板包括多個像素單元,每個像素單元可包含三個子像素,例如是第一子像素PX1、第二子像素PX2、第三子像素PX3。第一子像素PX1配置有紅光感測電路SR與綠光感測電路SG,第二子像素PX2配置有藍光感測電路SB與紫光感測電路SP,且第一子像素PX1相鄰於第二子像素PX2。其中第二子像素PX2配置的光感測電路即是如第14圖所示,整合感測藍光與感測紫光於同一電路。而上述的於一個子像素單元配置一個感測電路為示例性說明,在另一實施例中,亦可以是多個像素單元配置一個感測電路。FIG. 22 is a schematic diagram of a light sensing circuit and a pixel configuration according to the first embodiment of the present invention. In one embodiment, the display panel includes a plurality of pixel units, and each pixel unit may include three sub-pixels, such as a first sub-pixel PX1, a second sub-pixel PX2, and a third sub-pixel PX3. The first subpixel PX1 is configured with a red light sensing circuit SR and a green light sensing circuit SG, the second subpixel PX2 is configured with a blue light sensing circuit SB and a purple light sensing circuit SP, and the first subpixel PX1 is adjacent to the first subpixel PX1. Two sub-pixels PX2. The photo-sensing circuit configured in the second sub-pixel PX2 is shown in FIG. 14, which integrates sensing blue light and sensing purple light in the same circuit. The configuration of one sensing circuit in one sub-pixel unit is described as an example. In another embodiment, one sensing circuit may be configured in multiple pixel units.
第23圖繪示依照本發明第一實施例的光感測電路107示意圖。光感測電路107為充電式,光感測電路107與第14圖所示的光感測電路105架構類似,第五感光元件T5亦為可選擇性設置。差異點說明如下:於充電式光感測電路107,電容C1耦接的電壓源是低電壓VSL ,第二感光元件T2(及第五感光元件T5)耦接的電壓源是低電壓VSL 。第一開關元件TSW1 回應於第一控制信號Sn1(t)選擇性地導通,第二開關元件TSW2 回應於第二控制信號Sn2(t)選擇性地導通。第二感光元件T2更具有一控制端,用以接收重置切換信號SW(t)。FIG. 23 is a schematic diagram of a light sensing circuit 107 according to the first embodiment of the present invention. The photo-sensing circuit 107 is of a charging type. The photo-sensing circuit 107 is similar in structure to the photo-sensing circuit 105 shown in FIG. 14, and the fifth photosensitive element T5 is also selectively disposed. The differences are explained as follows: In the rechargeable light sensing circuit 107, the voltage source coupled to the capacitor C1 is a low voltage V SL , and the voltage source coupled to the second photosensitive element T2 (and the fifth photosensitive element T5) is a low voltage V SL . The first switching element T SW1 is selectively turned on in response to the first control signal Sn1 (t), and the second switching element T SW2 is selectively turned on in response to the second control signal Sn2 (t). The second photosensitive element T2 further has a control terminal for receiving the reset switching signal SW (t).
第23圖所示為一種充電式光感測電路的實施例,其中第二感光元件T2的控制端直接由外部給予重置切換信號SW(t),此為一種實作方式。在另一實施例中,第二感光元件T2亦可連接為二極體連接形式,將第二感光元件T2的控制端連接至低電壓VSL ,如此亦可以實現充電式光感測電路。FIG. 23 shows an embodiment of a rechargeable light sensing circuit, in which the control terminal of the second photosensitive element T2 directly gives a reset switching signal SW (t) from the outside, which is an implementation method. In another embodiment, the second photosensitive element T2 may also be connected in a diode connection form, and the control terminal of the second photosensitive element T2 is connected to a low voltage V SL , so that a rechargeable light sensing circuit can also be implemented.
第24圖繪示對應於第23圖電路的信號時序圖。第25圖繪示第23圖電路於第一重置時間區間的操作示意圖。於第一重置時間區間中,第一控制信號Sn1(t)為低電壓VSL 、第二控制信號Sn2(t)為低電壓VSL ,第一開關元件TSW1 不導通,第二開關元件TSW2 不導通。重置切換信號SW(t)為高電壓VSH ,第二感光元件T2受重置切換信號SW(t)控制而導通,因此如第25圖箭頭所示,對電容C1放電,使圖中感測電壓Va放電至低重置電位。第二重置時間區間的操作與第一重置時間區間相同,因此不再重複贅述。FIG. 24 shows a timing diagram of signals corresponding to the circuit of FIG. 23. FIG. 25 is a schematic diagram illustrating the operation of the circuit in FIG. 23 during the first reset time interval. In the first reset time interval, the first control signal Sn1 (t) is a low voltage V SL , the second control signal Sn2 (t) is a low voltage V SL , the first switching element T SW1 is not turned on, and the second switching element T SW2 is not conducting. The reset switching signal SW (t) is a high voltage V SH , and the second photosensitive element T2 is controlled by the reset switching signal SW (t) to be turned on. Therefore, as shown by the arrow in FIG. 25, the capacitor C1 is discharged to make the sense in the figure The measured voltage Va is discharged to a low reset potential. The operation of the second reset time interval is the same as that of the first reset time interval, and therefore will not be described repeatedly.
於第一感測時間區間,電壓源的電壓位準被提供至重置切換信號SW(t),因此重置切換信號SW(t)為低電壓VSL ,使得第二感光元件T2操作於次臨界區。第一控制信號Sn1(t)為高電壓VSH 、第二控制信號Sn2(t)為低電壓VSL ,因此第一開關元件TSW1 導通,第二開關元件TSW2 不導通。在第一感測時間區間,若照射紫光(紅光與藍光的混合光)於光感測電路107,則會使得感測電壓Va上升;若是照射白光於光感測電路107,第二感光元件T2亦會產生光電流,第二感光元件T2所產生的光電流將會降低節點電壓Vb。經由適當的設計,例如調整電晶體的尺寸或寬度,可以使得感測電壓Va對應於紫光的電壓值與對應於白光的電壓值不同,如此即可實現對環境光不敏感的光感測電路。In the first sensing time interval, the voltage level of the voltage source is provided to the reset switching signal SW (t), so the reset switching signal SW (t) is a low voltage V SL , so that the second photosensitive element T2 operates next time. Critical section. Since the first control signal Sn1 (t) is a high voltage V SH and the second control signal Sn2 (t) is a low voltage V SL , the first switching element T SW1 is turned on and the second switching element T SW2 is not turned on. In the first sensing time interval, if purple light (mixed light of red light and blue light) is irradiated on the light sensing circuit 107, the sensing voltage Va will increase; if white light is irradiated on the light sensing circuit 107, the second photosensitive element T2 also generates a photocurrent, and the photocurrent generated by the second photosensitive element T2 will reduce the node voltage Vb. Through proper design, such as adjusting the size or width of the transistor, the voltage value of the sensing voltage Va corresponding to the purple light and the voltage value corresponding to the white light can be different, so that a light sensing circuit that is insensitive to ambient light can be realized.
於第二感測時間區間,第一控制信號Sn1(t)為低電壓VSL 、第二控制信號Sn2(t)為高電壓VSH ,因此第一開關元件TSW1 不導通,第二開關元件TSW2 導通,此時光感測電路可以感測藍光,相關敘述可參考先前實施例。而第一取樣時間區間及第二取樣時間區間的操作亦與先前多個實施例類似,於此不再贅述。During the second sensing time interval, the first control signal Sn1 (t) is a low voltage V SL and the second control signal Sn2 (t) is a high voltage V SH . Therefore, the first switching element T SW1 is not turned on, and the second switching element T SW2 is turned on. At this time, the light sensing circuit can sense blue light. For related description, refer to the previous embodiment. The operations of the first sampling time interval and the second sampling time interval are also similar to the previous embodiments, and details are not described herein again.
根據上述第13圖~第25圖所繪示多個實施例的光感測電路,不論是放電式或充電式光感測電路,可將兩種色光的感測整合於同一電路,在時間軸上錯開對於不同色光的感測,而能夠使用單一電路交錯偵測兩種不同色光。如此可以提升電路感測更多不同顏色之應用,並且使得光感測電路之間的間距能夠縮短,而提升解析度,當應用於偵測光筆輸入時,可以讀取較細的光筆筆跡。並且由於開關元件的控制信號電性耦接至感光元件的一端,能夠共用控制信號,如此可以節省電路中所需的繞線面積,尤其當面臨大面板尺寸時,更能顯著地降低硬體成本與電路面積,並能夠提升畫素之開口率。According to the light sensing circuits of the multiple embodiments shown in Figures 13 to 25 above, whether it is a discharge type or a charging type light sensing circuit, the sensing of two kinds of colored light can be integrated into the same circuit, and in the time axis The detection of different colors is staggered, and a single circuit can be used to detect two different colors. This can improve the application of the circuit to sense more different colors, and make the distance between the light-sensing circuits shorter, and improve the resolution. When used to detect the input of the light pen, it can read the thin light pen handwriting. And because the control signal of the switching element is electrically coupled to one end of the photosensitive element, the control signal can be shared, which can save the winding area required in the circuit, especially when facing a large panel size, it can significantly reduce the hardware cost And circuit area, and can improve the aperture ratio of pixels.
綜上所述,雖然本發明已以實施例揭露如上,然其並非用以限定本發明。本發明所屬技術領域中具有通常知識者,在不脫離本發明之精神和範圍內,當可作各種之更動與潤飾。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。In summary, although the present invention has been disclosed as above with the embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope of the attached patent application.
100、101、102、103、104、105、106、107‧‧‧光感測電路100, 101, 102, 103, 104, 105, 106, 107‧‧‧ light sensing circuits
C1‧‧‧電容C1‧‧‧capacitor
CF1‧‧‧第一濾光元件CF1‧‧‧first filter element
CF2‧‧‧第二濾光元件CF2‧‧‧Second filter element
CF3‧‧‧第三濾光元件CF3‧‧‧third filter element
CF4‧‧‧第四濾光元件CF4‧‧‧Fourth Filter Element
CF5‧‧‧第五濾光元件CF5‧‧‧Fifth filter element
CF6‧‧‧第六濾光元件CF6‧‧‧ Sixth Filter
Gn(t)‧‧‧取樣電路TSH的控制信號Gn (t) ‧‧‧Control signal of sampling circuit TSH
OUT‧‧‧輸出節點OUT‧‧‧output node
PX1‧‧‧第一子像素PX1‧‧‧first sub-pixel
PX2‧‧‧第二子像素PX2‧‧‧Second Subpixel
PX3‧‧‧第三子像素PX3‧‧‧ Third sub-pixel
SB‧‧‧藍光感測電路SB‧‧‧Blue light sensing circuit
SG‧‧‧綠光感測電路SG‧‧‧Green Light Sensing Circuit
SP‧‧‧紫光感測電路SP‧‧‧Purple light sensing circuit
SR‧‧‧紅光感測電路SR‧‧‧Red light sensing circuit
Sn1(t)‧‧‧第一控制信號Sn1 (t) ‧‧‧first control signal
Sn2(t)‧‧‧第二控制信號Sn2 (t) ‧‧‧Second control signal
T1‧‧‧第一感光元件T1‧‧‧The first photosensitive element
T2‧‧‧第二感光元件T2‧‧‧Second photosensitive element
T3‧‧‧第三感光元件T3‧‧‧Third photosensitive element
T4‧‧‧第四感光元件T4‧‧‧Fourth photosensitive element
T5‧‧‧第五感光元件T5‧‧‧Fifth photosensitive element
T6‧‧‧第六感光元件T6‧‧‧sixth photosensitive element
TSH‧‧‧取樣電路T SH ‧‧‧Sampling circuit
TSW1‧‧‧第一開關元件T SW1 ‧‧‧The first switching element
TSW2‧‧‧第二開關元件T SW2 ‧‧‧Second switching element
Va‧‧‧感測電壓Va‧‧‧sensing voltage
Vb‧‧‧節點電壓Vb‧‧‧node voltage
VGH、VSH‧‧‧高電壓V GH , V SH ‧‧‧High voltage
VGL、VSL‧‧‧低電壓V GL , V SL ‧‧‧ low voltage
第1圖繪示依照本發明第一實施例的光感測電路示意圖。 第2圖繪示依照本發明第一實施例的光感測電路示意圖。 第3圖繪示依照本發明第一實施例的光感測電路示意圖。 第4圖繪示對應於第3圖電路的信號時序圖。 第5圖繪示第3圖電路於第一重置時間區間的操作示意圖。 第6圖繪示第3圖電路於第一感測時間區間的操作示意圖。 第7圖繪示第3圖電路於第一取樣時間區間的操作示意圖。 第8圖繪示第3圖電路於第二感測時間區間的操作示意圖。 第9圖繪示第3圖電路於第二取樣時間區間的操作示意圖。 第10圖繪示依照本發明第一實施例的光感測電路示意圖。 第11圖繪示對應於第10圖電路的信號時序圖。 第12圖繪示第11圖電路於第一重置時間區間的操作示意圖。 第13圖繪示依照本發明第一實施例的光感測電路示意圖。 第14圖繪示依照本發明第一實施例的光感測電路示意圖。 第15圖繪示對應於第14圖電路的信號時序圖。 第16圖繪示第14圖電路於第一重置時間區間的操作示意圖。 第17圖繪示第14圖電路於第一感測時間區間的操作示意圖。 第18圖繪示第14圖電路於第一取樣時間區間的操作示意圖。 第19圖繪示第14圖電路於第二感測時間區間的操作示意圖。 第20圖繪示第14圖電路於第二取樣時間區間的操作示意圖。 第21圖繪示依照本發明第一實施例的光感測電路示意圖。 第22圖繪示依照本發明第一實施例的光感測電路與像素配置示意圖。 第23圖繪示依照本發明第一實施例的光感測電路示意圖。 第24圖繪示對應於第23圖電路的信號時序圖。 第25圖繪示第23圖電路於第一重置時間區間的操作示意圖。FIG. 1 is a schematic diagram of a light sensing circuit according to a first embodiment of the present invention. FIG. 2 is a schematic diagram of a light sensing circuit according to a first embodiment of the present invention. FIG. 3 is a schematic diagram of a light sensing circuit according to a first embodiment of the present invention. FIG. 4 shows a timing diagram of signals corresponding to the circuit of FIG. 3. FIG. 5 is a schematic diagram illustrating the operation of the circuit in FIG. 3 during the first reset time interval. FIG. 6 is a schematic diagram illustrating the operation of the circuit in FIG. 3 during the first sensing time interval. FIG. 7 is a schematic diagram illustrating the operation of the circuit in FIG. 3 during the first sampling time interval. FIG. 8 is a schematic diagram illustrating the operation of the circuit in FIG. 3 during the second sensing time interval. FIG. 9 illustrates the operation of the circuit of FIG. 3 in the second sampling time interval. FIG. 10 is a schematic diagram of a light sensing circuit according to a first embodiment of the present invention. FIG. 11 shows a signal timing diagram corresponding to the circuit of FIG. 10. FIG. 12 is a schematic diagram illustrating the operation of the circuit in FIG. 11 during the first reset time interval. FIG. 13 is a schematic diagram of a light sensing circuit according to a first embodiment of the present invention. FIG. 14 is a schematic diagram of a light sensing circuit according to a first embodiment of the present invention. FIG. 15 shows a signal timing diagram corresponding to the circuit of FIG. 14. FIG. 16 is a schematic diagram illustrating the operation of the circuit in FIG. 14 during the first reset time interval. FIG. 17 is a schematic diagram illustrating the operation of the circuit of FIG. 14 in the first sensing time interval. FIG. 18 illustrates the operation of the circuit of FIG. 14 in the first sampling time interval. FIG. 19 is a schematic diagram illustrating the operation of the circuit of FIG. 14 in the second sensing time interval. FIG. 20 shows the operation of the circuit of FIG. 14 in the second sampling time interval. FIG. 21 is a schematic diagram of a light sensing circuit according to a first embodiment of the present invention. FIG. 22 is a schematic diagram of a light sensing circuit and a pixel configuration according to the first embodiment of the present invention. FIG. 23 is a schematic diagram of a light sensing circuit according to the first embodiment of the present invention. FIG. 24 shows a timing diagram of signals corresponding to the circuit of FIG. 23. FIG. 25 is a schematic diagram illustrating the operation of the circuit in FIG. 23 during the first reset time interval.
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US11676415B2 (en) | 2021-04-09 | 2023-06-13 | Innolux Corporation | Sensing device capable of improving sensing effect thereof |
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CN109889712B (en) * | 2019-03-11 | 2020-11-10 | 维沃移动通信(杭州)有限公司 | Pixel circuit, image sensor, terminal equipment and signal control method |
TWI689107B (en) * | 2019-04-10 | 2020-03-21 | 友達光電股份有限公司 | Optical sensor circuit and display panel |
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US5748303A (en) * | 1996-12-31 | 1998-05-05 | Intel Corporation | Light sensing device |
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GB2446821A (en) * | 2007-02-07 | 2008-08-27 | Sharp Kk | An ambient light sensing system |
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US11676415B2 (en) | 2021-04-09 | 2023-06-13 | Innolux Corporation | Sensing device capable of improving sensing effect thereof |
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