TWI476382B - Ambient light sensor with automatic gain control - Google Patents
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本發明有關於一種光感測器，且特別是一種環境光感測裝置。The present invention relates to a light sensor, and more particularly to an ambient light sensing device.
環境光感測器(Ambient Light Sensor，ALS)提供近似於人眼的光線反應。顯示器的亮度的管理可以延長行動式電池的壽命和提供最佳的視覺觀看經驗，不論顯示器是在室內或戶外使用。An Ambient Light Sensor (ALS) provides a light response that approximates the human eye. The management of the brightness of the display can extend the life of the mobile battery and provide the best visual viewing experience, whether the display is used indoors or outdoors.
在行動電話的應用方面，已著色的玻璃或是黑色的玻璃往往被使用於提升行動電話的外觀美感。然而，黑色玻璃帶給了環境光感測器一個特殊的挑戰，因為當環境光穿過黑色玻璃而射入光感測器時，環境光的光譜會被黑色玻璃改變(或失真)。黑色玻璃典型的穿透率如圖1所示。黑色玻璃對於紅外光(IR light)的光譜具有較高的穿透率。不像可見光光譜，所述紅外光光譜對於人眼是無法察覺的。In the application of mobile phones, colored glass or black glass is often used to enhance the aesthetic appearance of mobile phones. However, black glass belts present a particular challenge to ambient light sensors because the ambient light spectrum is altered (or distorted) by the black glass as ambient light passes through the black glass and into the light sensor. The typical penetration rate of black glass is shown in Figure 1. Black glass has a higher transmittance for the spectrum of infrared light (IR light). Unlike the visible light spectrum, the infrared spectrum is undetectable to the human eye.
隱藏在黑色玻璃後的光感測器可能需要相當廣的動態範圍，同時維持可以接收的解析度，藉此感測室內光(主要是具有相當低量紅外光的螢光燈或白色發光二極體光源)與戶外光(主要是具有相當大量紅外光的陽光)。Light sensors hidden behind black glass may require a fairly wide dynamic range while maintaining acceptable resolution, thereby sensing indoor light (mainly fluorescent or white-emitting diodes with relatively low amounts of infrared light) Body light source) with outdoor light (mainly sunlight with a considerable amount of infrared light).
現有的擴展光感測器的動態感測範圍的方式敘述如下。首先，光感測器的類比/數位轉換器(ADC)的輸出是與入射光在對數值域(Logarithmic Domain)是呈線性關係。再者，應該使用具有較高解析度的類比/數位轉換器的光感測器。例如：相較於16位元(16 bit)的類比/數位轉換器，使用20位元(20bit)的類比/數位轉換器可以提升動態感測範圍至16倍。然而，前者的實現方式會減低解析度。後者的實現方式會在提升解析度的同時，以成正比的方式增加類比/數位轉換器的資料轉換(data conversion)時間，如此會大幅度地減少光感測器的資料轉換速度。The manner in which the dynamic range of the existing photosensor is extended is described below. First, the output of the analog/digital converter (ADC) of the photosensor is linear with the incident light in the Logarithmic Domain. Furthermore, a light sensor with a higher resolution analog/digital converter should be used. For example: compared to 16 bits (16 Bit) analog/digital converter with a 20-bit (20-bit) analog/digital converter that boosts the dynamic sensing range to 16x. However, the implementation of the former will reduce the resolution. The latter implementation will increase the data conversion time of the analog/digital converter in a proportional manner while increasing the resolution, which will greatly reduce the data conversion speed of the photo sensor.
本發明提供一種環境光感測方法及其感測裝置，係依據入射環境光的強度，以智慧式的切換增益設定，如此可以擴展光感測器的動態感測範圍而不犧牲光感測器的解析度。The invention provides an ambient light sensing method and a sensing device thereof, which are set by intelligent switching gain according to the intensity of incident ambient light, so that the dynamic sensing range of the light sensor can be expanded without sacrificing the light sensor Resolution.
本發明實施例提供一種環境光感測方法，包括以下步驟：首先，獲得靈敏度設定與曝光時間，且依據靈敏度設定與曝光時間獲得光感測器的感測信號。然後，當感測信號為可獲得時，判斷感測信號的強度是否位於預設範圍內，其中預設範圍具有上限值以及下限值。接著，依據對感測信號的強度的判斷結果來更新光感測器的靈敏度設定與曝光時間。再來，依據更新後的靈敏度設定與曝光時間來獲得光感測器的感測信號。Embodiments of the present invention provide an ambient light sensing method, including the following steps: First, obtaining a sensitivity setting and an exposure time, and obtaining a sensing signal of the photo sensor according to the sensitivity setting and the exposure time. Then, when the sensing signal is available, it is determined whether the intensity of the sensing signal is within a preset range, wherein the preset range has an upper limit value and a lower limit value. Next, the sensitivity setting and the exposure time of the photo sensor are updated based on the determination result of the intensity of the sensing signal. Then, the sensing signal of the photo sensor is obtained according to the updated sensitivity setting and exposure time.
本發明實施例提供一種環境光感測方法，包括以下步驟：首先，獲得一靈敏度設定與一曝光時間，且依據該靈敏度設定與該曝光時間獲得一光感測器的一粗略感測信號，其中該粗略感測信號是在短於一曝光時間M倍的一粗略曝光時間之內獲得，其中M大於1。然後，當該粗略感測信號為可獲得時，判斷該粗略感測信號的強度是否位於一預設範圍內，其中該預設範圍具有一上限值以及一下限值。接著，當該粗略感測信號的強度不位於該預設範圍內時，更新該光感測器的該靈敏度設定與該曝光時間。再來，當該粗略感測信號的強度位於該預設範圍內時，依據更新後的該靈敏度設定與更新後的該曝光時間獲得該光感測器的一感測信號。An embodiment of the present invention provides an ambient light sensing method, including the following steps: First, obtaining a sensitivity setting and an exposure time, and obtaining a rough sensing signal of a photo sensor according to the sensitivity setting and the exposure time, wherein The coarse sensing signal is obtained within a coarse exposure time that is M times shorter than an exposure time, where M is greater than one. Then, when the coarse sensing signal is available, it is determined whether the strength of the coarse sensing signal is within a preset range, wherein the preset range has an upper limit value and a lower limit value. Then, when the intensity of the coarse sensing signal is not within the preset range, the sensitivity setting of the photo sensor is updated with the exposure time. Then, when the intensity of the coarse sensing signal is within the preset range, a sensing signal of the photo sensor is obtained according to the updated sensitivity setting and the updated exposure time.
本發明實施例提供一種環境光感測裝置，包括光感測器與控 制器。光感測器具有靈敏度設定，在被環境光照射時產生感測信號。控制器獲得靈敏度設定與曝光時間。控制器依據靈敏度設定以及曝光時間週期性地獲得光感測器之感測信號。控制器在感測信號為可獲得時判斷感測信號的強度是否位於預設範圍內。所述預設範圍具有上限值以及下限值。控制器依據對感測信號的強度的判斷結果更新光感測器之靈敏度設定以及曝光時間。控制器依據更新後的靈敏度設定以及更新後的曝光時間獲得感測信號。Embodiments of the present invention provide an ambient light sensing device, including a light sensor and a control Controller. The light sensor has a sensitivity setting that produces a sensing signal when illuminated by ambient light. The controller obtains the sensitivity setting and exposure time. The controller periodically obtains the sensing signal of the photo sensor according to the sensitivity setting and the exposure time. The controller determines whether the intensity of the sensing signal is within a preset range when the sensing signal is available. The preset range has an upper limit value and a lower limit value. The controller updates the sensitivity setting of the photo sensor and the exposure time according to the judgment result of the intensity of the sensing signal. The controller obtains the sensing signal according to the updated sensitivity setting and the updated exposure time.
本發明實施例提供一種環境光感測裝置，包括光感測器與控制器。光感測器具有靈敏度設定，在被環境光照射時產生感測信號。控制器獲得靈敏度設定與曝光時間。控制器依據靈敏度設定以及曝光時間獲得光感測器之粗略感測信號。粗略感測信號是在短於曝光時間M倍的粗略曝光時間之內獲得，其中M大於1。控制器在粗略感測信號為可獲得時判斷粗略感測信號的強度是否位於預設範圍內，其中預設範圍具有上限值以及下限值。當粗略感測信號的強度不位於預設範圍內時，控制器更新光感測器之靈敏度設定以及曝光時間。當粗略感測信號的強度位於預設範圍內時，控制器依據更新後的靈敏度設定以及更新後的曝光時間獲得感測信號。Embodiments of the present invention provide an ambient light sensing device, including a light sensor and a controller. The light sensor has a sensitivity setting that produces a sensing signal when illuminated by ambient light. The controller obtains the sensitivity setting and exposure time. The controller obtains a rough sensing signal of the photo sensor according to the sensitivity setting and the exposure time. The coarse sensing signal is obtained within a coarse exposure time that is M times shorter than the exposure time, where M is greater than one. The controller determines whether the strength of the rough sensing signal is within a preset range when the coarse sensing signal is available, wherein the preset range has an upper limit value and a lower limit value. When the intensity of the coarse sensing signal is not within the preset range, the controller updates the sensitivity setting of the photo sensor and the exposure time. When the intensity of the coarse sensing signal is within the preset range, the controller obtains the sensing signal according to the updated sensitivity setting and the updated exposure time.
為使能更進一步瞭解本發明之特徵及技術內容，請參閱以下有關本發明之詳細說明與附圖，但是此等說明與所附圖式僅係用來說明本發明，而非對本發明的權利範圍作任何的限制。The detailed description of the present invention and the accompanying drawings are to be understood by the claims The scope is subject to any restrictions.
1‧‧‧環境光感測裝置1‧‧‧ Ambient light sensing device
11‧‧‧光感測器11‧‧‧Light sensor
12‧‧‧控制器12‧‧‧ Controller
S101、S103、S105、S107、S201、S203、S205、S207‧‧‧步驟流程Steps S101, S103, S105, S107, S201, S203, S205, S207‧‧
T0、T1、T2、T3、T4‧‧‧時間點T0, T1, T2, T3, T4‧‧‧ time points
圖1是傳統的典型黑色玻璃對於入射光波長的響應的曲線圖。Figure 1 is a graph of the response of a typical typical black glass to the wavelength of incident light.
圖2A是本發明實施例提供的環境光感測裝置之方塊圖。2A is a block diagram of an ambient light sensing device according to an embodiment of the present invention.
圖2B是本發明實施例提供的環境光感測方法之流程圖。FIG. 2B is a flowchart of an ambient light sensing method according to an embodiment of the present invention.
圖3是本發明實施例提供的光感測器的輸出之曲線圖。FIG. 3 is a graph of an output of a photo sensor according to an embodiment of the present invention.
圖4是本發明實施例提供的當光感測器的取樣率甚短於實際 積分時間的情況下之時序圖。FIG. 4 is a diagram showing the sampling rate of the photosensor is very short compared to the actual embodiment provided by the embodiment of the present invention. Timing diagram in the case of integration time.
圖5是本發明實施例提供的當光感測器的取樣率與實際積分時間相近的情況下之時序圖。FIG. 5 is a timing diagram of a case where the sampling rate of the photosensor is close to the actual integration time provided by the embodiment of the present invention.
圖6是本發明實施例提供的光感測器實現強制重啟的時序圖。FIG. 6 is a timing diagram of a photo sensor according to an embodiment of the present invention for implementing a forced restart.
圖7是本發明另一實施例提供的環境光感測方法之流程圖。FIG. 7 is a flowchart of an ambient light sensing method according to another embodiment of the present invention.
圖8是本發明另一實施例提供的在實際資料積分之前進行粗資料積分的之時序圖。FIG. 8 is a timing diagram of performing coarse data integration before actual data integration according to another embodiment of the present invention.
環境光感測器的靈敏度可以被調整。依據進入光感測器的環境光，估計據此所量測到的電流是否超出光感測器所預設的線性感測範圍，如可以調整光感測器的靈敏度以供下次感測時使用。如此的自動增益演算法可以內建在感測晶片中或設計在感測晶片外的控制器的層級而被實現。依據本發明，光感測器的動態範圍可以延伸到1000倍，同時不犧牲光感測器的解析度與資料轉換(data conversion)速度。The sensitivity of the ambient light sensor can be adjusted. According to the ambient light entering the photo sensor, it is estimated whether the measured current exceeds the line sensing range preset by the photo sensor, and the sensitivity of the photo sensor can be adjusted for the next sensing. use. Such an automatic gain algorithm can be implemented built into the sense wafer or at the level of a controller designed to sense the outside of the wafer. According to the present invention, the dynamic range of the photo sensor can be extended to 1000 times without sacrificing the resolution and data conversion speed of the photo sensor.
光感測器的靈敏度可以被調整為在晶片上具有多種增益設定，或將光感測器以多個單位的時間框(Time Frame)(或稱為訊框)來曝光，或者混和上述的兩種方式。圖2A揭示環境光感測裝置1包括光感測器11和控制器12。The sensitivity of the light sensor can be adjusted to have multiple gain settings on the wafer, or to expose the light sensor in multiple units of Time Frame (or frame), or to mix the above two Ways. 2A discloses that the ambient light sensing device 1 includes a light sensor 11 and a controller 12.
圖2B揭示自動增益控制演算法以主控制器依據入射的環境光來自動調整光感測器的靈敏度設定的方式實現。在步驟S101中，獲得靈敏度設定、曝光時間，且依據靈敏度設定與曝光時間獲得光感測器的感測信號。此演算法起始於讀取光感測器的狀態暫存器，狀態暫存器將光感測器的電流的靈敏度設定(與增益有關)、曝光時間(或稱為積分時間)告知控制器。如果光感測器是可用時，新的資料可以被獲得(即感測信號為可獲得)。2B discloses that the automatic gain control algorithm is implemented in such a manner that the main controller automatically adjusts the sensitivity setting of the photosensor according to the incident ambient light. In step S101, the sensitivity setting, the exposure time are obtained, and the sensing signal of the photo sensor is obtained according to the sensitivity setting and the exposure time. The algorithm starts with reading the state register of the photo sensor, and the state register informs the controller of the sensitivity setting (related to the gain) and the exposure time (or the integration time) of the current of the photo sensor. . If a light sensor is available, new material can be obtained (ie, the sensing signal is available).
接下來，在步驟S103中，當感測信號為可獲得時，判斷感測信號的強度是否位於預設範圍內，其中預設範圍具有一個上限值以及一個下限值。當新的感測信號NDATA是可獲得時，控制器可以由光感測器的資料暫存器讀取感測信號，並判斷感測信號NDATA是否在預設的(線性)範圍內(NDATA_MIN<NDATA<NDATA_MAX)。其中，NDATA_MAX是上限值，NDATA_MIN是下限值。Next, in step S103, when the sensing signal is available, it is determined whether the intensity of the sensing signal is within a preset range, wherein the preset range has an upper limit value and a lower limit value. When the new sensing signal NDATA is available, the controller may read the sensing signal from the data buffer of the photo sensor and determine whether the sensing signal NDATA is within a preset (linear) range (NDATA_MIN< NDATA<NDATA_MAX). Among them, NDATA_MAX is the upper limit and NDATA_MIN is the lower limit.
接著，在步驟S105中，依據對感測信號的強度的判斷結果來更新光感測器的靈敏度設定與曝光時間。當感測信號NDATA是大於上限值時，減少光感測器的靈敏度一個刻度(GAIN=GAIN-1，例如圖3所示的由GAIN2改變至GAIN1)。當感測信號NDATA的強度是位於預設範圍內(NDATA_MIN<NDATA<NDATA_MAX)時，維持光感測器的靈敏度。換句話說，如果感測信號NDATA的強度是位於(線性的)預設範圍內，光感測器的靈敏度不需要改變，且光感測器將可用目前的增益設定(對應於靈敏度)繼續下次的量測。如果感測信號NDATA是大於上限值NDATA_MAX，此時可能光感測器已經飽和，光感測器的靈敏度則可以被減少一個刻度，以供下次的量測。同樣地，如果感測信號NDATA是小於下限值NDATA_MIN，此時可能光感測器沒有足夠的靈敏度來真測較弱的環境光，且光感測器的資料轉換可能敏感於量子誤差(quantization error)，則光感測器的靈敏度可以被增加一個刻度，以供下次的量測。所導致的新的增益設定(或稱為靈敏度設定)可以分別被更新至增益暫存器和曝光時間暫存器，且下一次的資料轉換會基於此更新後的設定。Next, in step S105, the sensitivity setting and the exposure time of the photo sensor are updated in accordance with the determination result of the intensity of the sensing signal. When the sensing signal NDATA is greater than the upper limit value, the sensitivity of the photo sensor is reduced by one scale (GAIN=GAIN-1, for example, changed from GAIN2 to GAIN1 as shown in FIG. 3). When the intensity of the sensing signal NDATA is within a preset range (NDATA_MIN<NDATA<NDATA_MAX), the sensitivity of the photo sensor is maintained. In other words, if the intensity of the sensing signal NDATA is within a (linear) preset range, the sensitivity of the photosensor does not need to be changed, and the photosensor will continue to be available with the current gain setting (corresponding to sensitivity). Sub-measurement. If the sensing signal NDATA is greater than the upper limit value NDATA_MAX, then the photo sensor may be saturated at this time, and the sensitivity of the photo sensor may be reduced by one scale for the next measurement. Similarly, if the sensing signal NDATA is less than the lower limit value NDATA_MIN, then the photo sensor may not have sufficient sensitivity to actually measure the weak ambient light, and the data conversion of the photo sensor may be sensitive to quantum error (quantization) Error), the sensitivity of the light sensor can be increased by one scale for the next measurement. The resulting new gain setting (or sensitivity setting) can be updated to the gain register and the exposure time register, respectively, and the next data conversion will be based on this updated setting.
另外，前面所定義的預設範圍可以增加遲滯項，以避免光感測器的增益設定(或靈敏度設定)的切換過於頻繁，尤其是在感測信號NDATA相當接近於的預設範圍的邊界時，或者是因為相鄰的增益設定之間的繼承的增益誤差(inherited gain error)。例如：線性的 預設範圍可以是(NDATA_MIN*(1-HYS))<NDATA<(NDATA_MAX*(1+HYS))，其中，HYS是遲滯因子。如此，上限值NDATA_MAX是加上第一遲滯項HYS*NDATA_MAX而被增加，下限值NDATA_MIN是減去第二遲滯項HYS*NDATA_MIN而被減少。In addition, the preset range defined above may increase the hysteresis term to avoid switching the gain setting (or sensitivity setting) of the photo sensor too frequently, especially when the sensing signal NDATA is relatively close to the boundary of the preset range. Or because of the inherited gain error between adjacent gain settings. For example: linear The preset range may be (NDATA_MIN*(1-HYS))<NDATA<(NDATA_MAX*(1+HYS)), where HYS is a hysteresis factor. Thus, the upper limit value NDATA_MAX is increased by adding the first hysteresis term HYS*NDATA_MAX, and the lower limit value NDATA_MIN is decreased by subtracting the second hysteresis term HYS*NDATA_MIN.
圖3揭示了利用自動增益控制演算法實現的光感測器因應於環境光的輸出之曲線圖。若沒有自動增益的控制，在光感測器飽和或者光感測器的感測效果受到類比/數位轉換器的量子誤差影響之前，則光感測器只能偵測介於103 倍(1000倍)的照度範圍內的環境光，例如：可參考，增益GAIN2的範圍，其範圍介於數個轉換成數(converted count)至1000個轉換成數之間。若具有自動增益演算法，光感測器所能感測到的環境光可以涵蓋106 倍(1,000,000倍)的照度範圍。Figure 3 reveals a graph of the photosensors that are implemented using an automatic gain control algorithm in response to ambient light output. Without automatic gain control, the photo sensor can only detect between 10 3 times (1000 before the photo sensor is saturated or the sensing effect of the photo sensor is affected by the quantum error of the analog/digital converter). Ambient light in the range of illumination, for example: reference, the range of gain GAIN2, ranging from a number of converted counts to 1000 converted into numbers. If with automatic gain algorithm, the light sensor can be sensed ambient light may encompass 106-fold (1,000,000-fold) range of illumination.
接著，在步驟S107中，依據更新後的靈敏度設定與曝光時間來獲得光感測器的感測信號。在步驟S107之後，整體的增益控制的循環可以配合更新後的增益和曝光時間被再重新執行一次。Next, in step S107, the sensing signal of the photo sensor is obtained according to the updated sensitivity setting and the exposure time. After step S107, the overall gain control loop can be re-executed again in conjunction with the updated gain and exposure time.
更進一步，獲得光感測器的感測信號的方式(即步驟S101)可以一個取樣時間來被週期性地執行。所述取樣時間包括資料積分時間與待命時間，其中資料積分時間是曝光時間。圖4繪示了當光感測器使用的取樣率甚慢於實際的資料積分時間的情況下之時序圖。這是在行動電話的典型的應用情況，藉此可以減少光感測器的功率消耗。光感測器的資料的取樣週期或量測週期可以時間區間T2-T0來定義，此時實際的資料積分時間或曝光時間是以時間區間T1-T0來定義。在時間區間T2-T1內，光感測器可以待命或在睡眠模式，藉此減少光感測器的總電流消耗(亦即功率消耗)。光感測器可以在時間T2被喚醒以進行新的資料積分動作。當控制器的資料擷取率至少是快於光感測器的資料取樣率的兩倍以上時，在光感測器進行下次資料取樣的週期前，新獲得的增益設定 (如果有需要的話)可以及時被更新。Further, the manner in which the sensing signal of the photo sensor is obtained (ie, step S101) can be performed periodically with one sampling time. The sampling time includes a data integration time and a standby time, wherein the data integration time is an exposure time. Figure 4 depicts a timing diagram when the sampling rate used by the photosensor is slower than the actual data integration time. This is a typical application in mobile phones, whereby the power consumption of the light sensor can be reduced. The sampling period or measurement period of the data of the photo sensor can be defined by the time interval T2-T0, and the actual data integration time or exposure time is defined by the time interval T1-T0. Within the time interval T2-T1, the light sensor can be on standby or in a sleep mode, thereby reducing the total current consumption (ie, power consumption) of the light sensor. The light sensor can be woken up at time T2 for a new data integration action. When the data acquisition rate of the controller is at least twice faster than the data sampling rate of the photo sensor, the newly obtained gain setting is performed before the period in which the photo sensor performs the next data sampling. (If needed) can be updated in a timely manner.
圖5繪示了當光感測器使用的取樣率相當接近於於實際的資料積分時間的情況下之時序圖。既然控制器的資料擷取率是與光感測器的資料取樣率相當，如此有很高的機率使獲得的增益設定是在光感測器進行下次資料取樣的週期開始後才被更新。如此，為了反映出具有更新後的增益設定的資料，將會有至少一個且至多有兩個的取樣週期的延遲(T4-T2)。Figure 5 illustrates a timing diagram when the sampling rate used by the photosensor is fairly close to the actual data integration time. Since the data acquisition rate of the controller is equivalent to the data sampling rate of the photosensor, there is a high probability that the gain setting obtained is updated after the photosensor performs the next data sampling period. Thus, in order to reflect the data with the updated gain setting, there will be at least one and at most two sampling period delays (T4-T2).
為了使反映出具有更新後的增益設定的資料的時間最小化，光感測器可以實施一個強制重啟的特徵，此特徵允許使用者以更新後的增益設定來重新啟動資料取樣週期，不論光感測器是在睡眠模式(sleep mode)或主動模式(active mode)。換句話說，為了獲得光感測器的感測信號，控制器可以執行一個強制重啟程序以在取樣週期內(T2-T0)之任一時間點重新獲得感測信號。In order to minimize the time reflecting the data with the updated gain setting, the light sensor can implement a forced restart feature that allows the user to restart the data sampling period with the updated gain setting, regardless of the light perception. The detector is in sleep mode or active mode. In other words, in order to obtain the sensing signal of the photo sensor, the controller may perform a forced restart procedure to regain the sensing signal at any point in the sampling period (T2-T0).
圖6揭示光感測器實現強制重啟的時序圖。如圖6所示，新的資料在時間T2被讀取，加設此資料的強度是落在光感測器工作的靈敏度的預設範圍之外，新的增益設定將在時間T3被更新。光感測器可以被強制重啟，即使光感測器是在執行資料積分的過程當中。如此，將只有一個短暫的延遲(T4-T2)，所述短暫的延遲歸因於暫存器的更新延遲和光感測器的強制重啟的延遲，相較於資料取樣週期，所述延遲是可以被忽略的。Figure 6 shows a timing diagram of a photo sensor implementing a forced restart. As shown in FIG. 6, the new data is read at time T2, the intensity of the added data is outside the preset range of sensitivity of the photosensor operation, and the new gain setting will be updated at time T3. The light sensor can be forced to restart even if the light sensor is in the process of performing data integration. As such, there will be only a short delay (T4-T2) due to the update delay of the scratchpad and the delay of the forced restart of the photosensor, which is comparable to the data sampling period. Neglected.
本發明的另一實施例揭露，在實際的資料積分之前實施一個粗略資料積分程序，以在開始一個完整的資料積分(即實際的資料積分)之前先判斷光感測器的電流水平的最佳的增益設定。粗資料積分意指，犧牲光感測器的解析度以獲得較快的資料轉換速度。如果光感測器的解析度減少M倍，則資料轉換速度所花的時間也可以被減少M倍。Another embodiment of the present invention discloses that a rough data integration procedure is implemented prior to actual data integration to determine the best current level of the photosensor before starting a complete data integration (ie, actual data integration). Gain setting. The coarse data integration means that the resolution of the light sensor is sacrificed to obtain a faster data conversion speed. If the resolution of the light sensor is reduced by a factor of M, the time taken for the data conversion speed can also be reduced by a factor of M.
即使粗資料積分所得的資料的解析度低於實際的資料積分的 解析度，粗資料積分所得的資料仍足以用於找尋最佳的增益設定。圖7揭示了利用粗資料積分方式實現的流程圖。首先，在步驟S201中，獲得靈敏度設定、曝光時間，且依據靈敏度設定與曝光時間獲得光感測器的粗略感測信號，其中粗略感測信號是在短於曝光時間M倍的粗略曝光時間之內獲得，其中M大於1。接著在步驟S203中，當粗略感測信號為可獲得時，判斷粗略感測信號的強度是否位於預設範圍內，其中預設範圍具有一個上限值NDATA_MAX/M以及一個下限值NDATA_MIN/M。上限值NDATA_MAX/M是比前一實施例的上限值NDATA_MAX小M倍。下限值NDATA_MIN/M是比前一實施例的下限值NDATA_MAX小M倍。Even if the data obtained from the rough data points has a lower resolution than the actual data points The resolution, the data obtained from the rough data integration is still sufficient to find the best gain setting. Figure 7 discloses a flow chart implemented using a coarse data integration method. First, in step S201, a sensitivity setting, an exposure time are obtained, and a coarse sensing signal of the photo sensor is obtained according to the sensitivity setting and the exposure time, wherein the rough sensing signal is a rough exposure time shorter than M times of the exposure time. Obtained internally, where M is greater than one. Next, in step S203, when the coarse sensing signal is available, it is determined whether the strength of the rough sensing signal is within a preset range, wherein the preset range has an upper limit value NDATA_MAX/M and a lower limit value NDATA_MIN/M . The upper limit value NDATA_MAX/M is M times smaller than the upper limit value NDATA_MAX of the previous embodiment. The lower limit value NDATA_MIN/M is M times smaller than the lower limit value NDATA_MAX of the previous embodiment.
另外，當考慮遲滯因子，線性的預設範圍可以是(NDATA_MIN/M *(1-HYS))<NDATA<(NDATA_MAX/M *(1+HYS))，其中HYS是遲滯因子。如此，上限值NDATA_MAX/M是加上第一遲滯項HYS*NDATA_MAX/M而被增加，下限值NDATA_MIN/M是減去第二遲滯項HYS*NDATA_MIN/M而被減少。In addition, when considering the hysteresis factor, the linear preset range may be (NDATA_MIN/M*(1-HYS))<NDATA<(NDATA_MAX/M*(1+HYS)), where HYS is a hysteresis factor. Thus, the upper limit value NDATA_MAX/M is increased by adding the first hysteresis term HYS*NDATA_MAX/M, and the lower limit value NDATA_MIN/M is decreased by subtracting the second hysteresis term HYS*NDATA_MIN/M.
如果粗略感測信號不是在預設範圍內，則進行步驟S205。在步驟S205中，更新光感測器的靈敏度設定與曝光時間。值得一提的是，粗略曝光時間可以被更新，當曝光時間被更新時，因為粗略曝光時間是比曝光時間小M倍。光感測器的靈敏度設定可以依據下述的方式被更新。當粗略感測信號NDATA’的強度大於上限值NDATA_MAX/M時，控制器減少光感測器的靈敏度一刻度。當粗略感測信號NDATA’的強度小於下限值NDATA_MIN/M時，控制器增加光感測器的靈敏度一刻度。或者，當粗略感測信號NDATA’的強度位於預設範圍(NDATA_MAX/M<NDATA’<NDATA_MIN/M)內時，控制器維持光感測器的靈敏度。在步驟S205之後，再次執行步驟S201。If the rough sensing signal is not within the preset range, step S205 is performed. In step S205, the sensitivity setting and exposure time of the photo sensor are updated. It is worth mentioning that the coarse exposure time can be updated when the exposure time is updated because the coarse exposure time is M times smaller than the exposure time. The sensitivity setting of the photo sensor can be updated in the following manner. When the intensity of the coarse sensing signal NDATA' is greater than the upper limit value NDATA_MAX/M, the controller reduces the sensitivity of the photosensor by one scale. When the intensity of the coarse sensing signal NDATA' is less than the lower limit value NDATA_MIN/M, the controller increases the sensitivity of the photosensor by one scale. Alternatively, when the intensity of the coarse sensing signal NDATA' is within a preset range (NDATA_MAX/M < NDATA' < NDATA_MIN/M), the controller maintains the sensitivity of the photo sensor. After step S205, step S201 is performed again.
如果粗略感測信號NDATA’的強度是位於預設範圍內，則進行步驟S207。在步驟S207中，依據更新後的靈敏度設定與更新後的曝光時間獲得光感測器的感測信號NDATA(進行實際資料積分來獲得)。If the intensity of the coarse sensing signal NDATA' is within the preset range, step S207 is performed. In step S207, the sensing signal NDATA of the photo sensor is obtained according to the updated sensitivity setting and the updated exposure time (obtained by actual data integration).
換句話說，當光感測器以比曝光時間少M倍的粗略曝光時間進行資料積分時，光感測器所輸出的資料可以預期是比完整的資料積分小M倍。同樣地，線性的預設範圍的邊界也是小了M倍。所以，粗資料積分的資料是與預設範圍的邊界NDATA_MIN/M與NDATA_MAX/M做比較。進行粗資料積分的循環可能會重複進行幾次，直到最佳的增益設定被找到。完整的資料積分將依據被找到的最佳增益設定來進行。另一個新的資料積分的循環可以由粗資料積分與最新得到的增益設定而再次地重複。In other words, when the light sensor performs data integration with a coarse exposure time that is M times less than the exposure time, the data output by the light sensor can be expected to be M times smaller than the complete data integration. Similarly, the boundaries of the linear preset range are also M times smaller. Therefore, the data of the coarse data integration is compared with the boundary of the preset range NDATA_MIN/M and NDATA_MAX/M. The loop for coarse data integration may be repeated several times until the optimal gain setting is found. The complete data score will be based on the best gain setting found. Another new cycle of data integration can be repeated again by the coarse data integration and the latest gain setting.
圖8揭示了在進行實際資料積分之前先進行粗資料積分的實線方式的時序圖。粗資料積分時間(T2-T0)應該比實際資料積分區間(T4-T2)短很多，以致於粗資料積分將不會明顯地降低光感測器的整體資料轉換速率(T4-T0)。此種實現方式也可以確保每一個實際資料積分依據光源的強弱來使用最佳的增益設定。Figure 8 shows a timing diagram of the solid line mode of coarse data integration prior to actual data integration. The coarse data integration time (T2-T0) should be much shorter than the actual data integration interval (T4-T2), so that the coarse data integration will not significantly reduce the overall data conversion rate (T4-T0) of the photosensor. This implementation also ensures that each actual data integration uses the best gain setting depending on the strength of the light source.
綜上所述，本發明實施例所提供的環境光感測方法及其感測裝置，可以擴展光感測器的動態範圍而不降低光感測器的解析度，同時光感測器的資料轉換速率可能不會明顯地降低。粗資料積分程序可以被應用來減少光感測器的資料轉換時間。環境光感測器的靈敏度可以依據評估量測到的入射的環境光是否超出光感測器的(線性的)預設範圍，以致於光感測器的靈敏度可以被調整且用於下一次的光量測。此種自動增益控制的演算法可以以內建於光感測器的晶片而實現，或者實現在在光感測器晶片之外的控制器的層級。依據本發明實施例所述，光感測器的動態感測範圍可以被擴展至1000倍，而不犧牲光感測器的解析度和資料轉換速度。更 進一步，強制重啟程序可以應用到此方法以提升資料轉換速率。In summary, the ambient light sensing method and the sensing device provided by the embodiments of the present invention can expand the dynamic range of the light sensor without reducing the resolution of the light sensor, and the data of the light sensor. The conversion rate may not be significantly reduced. The coarse data integration procedure can be applied to reduce the data conversion time of the light sensor. The sensitivity of the ambient light sensor can be based on the estimated measured ambient light that exceeds the (linear) preset range of the light sensor, so that the sensitivity of the light sensor can be adjusted and used for the next time. Light measurement. Such automatic gain control algorithms can be implemented with a chip built into the photosensor or at the level of the controller outside of the photosensor wafer. According to the embodiment of the invention, the dynamic sensing range of the photo sensor can be extended to 1000 times without sacrificing the resolution of the photo sensor and the data conversion speed. more Further, a forced restart procedure can be applied to this method to increase the data conversion rate.
以上所述僅為本發明之實施例，其並非用以侷限本發明之專利範圍。The above description is only an embodiment of the present invention, and is not intended to limit the scope of the invention.
S101、S103、S105、S107‧‧‧步驟流程S101, S103, S105, S107‧‧‧ step procedure
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| US5003288A (en) * | 1988-10-25 | 1991-03-26 | Nartron Corporation | Ambient light sensing method and apparatus |
| EP1569194A1 (en) * | 2004-02-13 | 2005-08-31 | Sony Ericsson Mobile Communications AB | Portable electronic device controlled according to ambient illumination |
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| TW201435314A (en) | 2014-09-16 |
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