PHP中文字符转数组

//汉字字符转数组
     function chStrToArray($str){
        $length = mb_strlen($str, 'utf-8');
        $array = array();
        for ($i=0; $i<$length; $i++)
            $array[] = mb_substr($str, $i, 1, 'utf-8');
        return $array;
    }