A high performance MEMS platform for actuation and sensing

我们的研究小组最近开发了一种超薄(0.5 mm)新型三自由度微型静电执行器平台，并通过初步实施实例展示了其作为平台的潜力，可以解决微型静电执行器长期存在的问题，以及作为高性能微型加速度计和力微型传感器的应用。微致动器平台的制造和测试显示了高达100毫克质量块和100微米冲程的大作用力产生和操纵。该技术还需要进一步开发，以实现智能手机相机的自动对焦和光学稳像。要开发的相机模块使用新型致动器来实现自动对焦，该自动对焦基于沿光轴的平移和沿形成垂直于图像传感器的光轴的平面的轴的2轴旋转。使用图像传感器驱动实现自动对焦提供了几乎瞬间的对焦，在这种对焦中，相机可以在很短的时间内将焦点从一个场景切换到另一个场景。另一个优势是执行器的高分辨率(±1微米)，而不是目前广泛使用的电磁音圈电机技术(VCM)的±10微米分辨率。这种高分辨率使大口径相机的使用成为可能，从而使更多的光线进入图像传感器。OIS功能将通过使用第二个微致动器作用于镜筒来实现。 这款相机在手机中广泛使用，使用时会出现明显的电池耗尽现象。与目前使用的电磁VCM相比，微执行器平台有望通过使用静电驱动技术来显著降低功耗。我们的执行器的峰值功率要求约为1毫瓦，而典型VCM的峰值功率要求为100-200毫瓦。该技术在智能手机等手持设备中的实现要求MEMS致动器的工作电压被限制在37V。需要进一步开发这项技术，以便在微芯片内实现图像传感器信号的路由，并将所需的电压从80V降低到最高37V。还需要进一步的开发，通过允许相机的每个图像传感器和镜筒的三个自由度运动来同时实现自动对焦和光学图像稳定。微静电平台还将被实施，以开发智能手机的3D触摸屏，将其作为基于单一透明层的超灵敏力和位置传感器。由于设计本身的原因，它还将被实施为多轴加速度计，其特点是大范围、宽带宽、超低噪声底限和非常高的灵敏度，并且被证明是唯一适合于许多需要非常高灵敏度的应用。

We have recently developed in our research group an ultra-thin (0.5 mm) novel 3-degrees-of-freedom micro-electrostatic actuator platform and shown through initial implementation examples its potential as a platform that can address long standing problems of micro electrostatic actuators as well as its use as a high performance micro accelerometer and force micro sensor. The micro actuator platform was fabricated and tested to demonstrate large force generation and manipulation of up to 100 milligram size masses and a stroke of 100 µm. Further development of the technology is needed for its implementation for autofocus (AF) and optical image stabilization (OIS) in smart phone cameras. The camera modules to be developed use the novel actuator to achieve AF based on translation along the optical axis and 2 axis rotation along axes forming the plane perpendicular to the optical axis of the image sensor. Achieving AF using image sensor actuation provides almost instant focus in which the camera switches the focus form one scene to another in a very short time. Another advantage is the high resolution (±1µm) of the actuator as opposed to ±10 µm resolution of the currently widely used electromagnetic Voice Coil motor technology (VCM). This high resolution enables the use of large aperture cameras which allow more light to enter the image sensor. The OIS feature will be pursued by acting on the lens barrel by using a second micro actuator. The camera is widely used in mobile phones and a significant battery drain is observed when used. The micro-actuator platform is expected to significantly reduce the power consumption by using electrostatic actuation technology as opposed to electromagnetic VCMs currently in use. The peak power requirement for our actuator is of the order of 1 mWatt as opposed to 100-200 mWatt for typical VCMs. The implementation of the technology in handheld devices such as smart phones requires that the operating voltages for the MEMS actuators are limited to 37V. Further development of the technology is needed to enable image sensor signal routing within the micro-chip and lower the required voltage from 80V to a maximum of 37V. Further development is also needed to achieve simultaneously autofocus and optical image stabilization by enabling 3 degrees of freedom motion of each the image sensor and lens barrel of the camera. The micro-electrostatic platform will also be implemented to develop 3D touch screens in smart phones by using it as an ultra sensitive force and position sensor based on a single transparent layer. It is also to be implemented as multi-axis accelerometers that are characterized by large range, wide bandwidth, ultra low noise floor and very high sensitivity due to the design itself and is shown to be uniquely suitable for a number of applications requiring very high sensitivity.