为了进一步提高多元线性阵列超声换能器的方向特性，采用多元相控聚焦的方法,研究了多元线性阵列超声换能器的主频、阵元个数和阵元间距对其方向性的影响。结果表明，当超声换能器的主频较低时，可以采用较大尺寸的阵元组;而对于主频较高的超声换能器，阵元尺寸应该取小一些，其方向性较好。这将有利于光声信号的探测与成像。

In order to develop the direction property of a multi-element linear ultrasonic transducer array, the effect of its dominant frequency, element number and space between the elements on its direction was studied based on the multi-element phase-controlled technique. These results show that for good direction property, a large size array could be used when the main frequency of the transducer is low; on the contrary, for high frequency transducers, a smaller size array should be used. This is beneficial for photoacoustic detection and imaging.