多功能傳感器縮短設計時間

　　多功能傳感器，結合近距離和環境光傳感可能是智能手機設計師誰尋求節省更多的權力，減少房地產，并縮短其設計周期，以滿足他們的時間到市場需求的答案。

　　這些高度集成的設備旨在節省能源，延長電池壽命，并在各種照明環境中提供優化的觀看。這在智能手機應用中通常是必須具備的，并帶有多媒體功能和觸摸屏操作。

　　環境光傳感器（ALS）通過檢測環境光亮度來控制lcd屏幕的亮度。接近傳感器檢測當手機靠近用戶的面部或耳朵以降低LCD屏幕的功耗以降低功耗。它還禁用液晶屏幕，以防止用戶在電話交談時不小心輸入。

　　這些集成的設備也可以在許多其他消費電子應用中使用，并可能在平板電腦、GPS設備、數碼相機以及工業型應用中找到家園。

　　Initially， these “2-in-1” multifunction devices only integrated the ambient light sensor and the proximity photodiode. The IR emitter （LED） was separate， which resulted in several challenges concerning the design of a shield， or barrier， to keep the emitter separate from the photodiode to prevent crosstalk， which impacts the performance of the proximity sensor.

　　Now， sensors such as Vishay Intertechnology‘s VCNL4000 series （Figure 1） fully integrated proximity and ambient light optical sensor contains all the circuitry （IR emitter， photo-pin-diode， ambient light detector， signal processing IC and 16-bit ADC） needed in one device to eliminate the need for light barriers and optical alignment of the IR emitter and photodiode. It’s also housed in a small package， measuring 3.95 x 3.95 x 0.75 mm， for further board space savings. The VCNL4000 series comes with an I2C communication interface， which further simplifies design. Vishay also offers the device in a rectangular package， designated as the VCNL4020.