设计了一种模仿视网膜内光感受器工作机理的高性能光电转换阵列。该阵列将入射的自然光照转换成高电平持续时间固定而频率与入射光强度成比例的电脉冲信号。在标准的0.5μm CMOS工艺上完成了电路的设计和验证。采用独特的结构和方法,对电路的几个关键参数进行了优化,电路的动态范围达70dB以上,保证了它在一般自然光照的强度范围内都能可靠地工作;单个像元消耗的电流约为0.62~1.46μA,像元尺寸约为53μm×50μm,有利于实现光电转换阵列的高密度集成和射频无线能量供应方式,因而更适合用于视觉修复。
A high performance optic-to-electrical array for visual recovery is proposed by imitating the mechanisms of photoreceptor in a human retina. The array can transform the incident natural light into a pulse signal, which pulse width is a constant and frequency is proportional to the light intensity. Design and verification of the chip has been completed in standard 0.5 μm CMOS process. Unique structures and methods are employed to optimize several key parameters and obtained higher performance. The pulse width is 0.13 ms and the pixel acquires 70 dB dynamic range, thus it can work reliably in common natural light scope. The pixel size is about 53μm×50μm and the power consumption is 0.62-1.46 μA per pixel. The experimental results show that the presented optic-to-electrical array is suitable to be high density integrated and to be wireless radio frequency powered, and therefore more suited for retinal prosthesis.