icalendar事件时区与用户时区不匹配

我通过邮件将事件发送到MS outlook，但事件时间与我发送的不同。

我还想支持所有应用程序的icalender事件，如微软Outlook，谷歌日历。。etc

任何用于实现icalendar事件的好资源或api都可以告诉我。例如

发送：

Start Time : 12:40 P.M.
End Time   : 01:00 P.M.

在用户端，Outlook在1小时后显示事件。

Start Time : 01:40 P.M.
End Time   : 02:00 P.M.

我想要与我发送的结果相同的结果。

下面是我的icalendar代码。

$ical = 'BEGIN:VCALENDAR' . "'r'n" .
        'PRODID:-//Microsoft Corporation//Outlook 10.0 MIMEDIR//EN' . "'r'n" .
        'VERSION:2.0' . "'r'n" .
        'METHOD:REQUEST' . "'r'n" .
        'BEGIN:VTIMEZONE' . "'r'n" .
        'TZID:'.date_default_timezone_get() . "'r'n" .
        'BEGIN:STANDARD' . "'r'n" .
        'DTSTART:20091101T020000' . "'r'n" .
        'RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=1SU;BYMONTH=11' . "'r'n" .
        'TZOFFSETFROM:-0400' . "'r'n" .
        'TZOFFSETTO:-0500' . "'r'n" .
        'TZNAME:EST' . "'r'n" .
        'END:STANDARD' . "'r'n" .
        'BEGIN:DAYLIGHT' . "'r'n" .
        'DTSTART:20090301T020000' . "'r'n" .
        'RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=2SU;BYMONTH=3' . "'r'n" .
        'TZOFFSETFROM:-0500' . "'r'n" .
        'TZOFFSETTO:-0400' . "'r'n" .
        'TZNAME:EDST' . "'r'n" .
        'END:DAYLIGHT' . "'r'n" .
        'END:VTIMEZONE' . "'r'n" .  
        'BEGIN:VEVENT' . "'r'n" .
        'ORGANIZER;CN="'.$from_name.'":MAILTO:'.$from_address. "'r'n" .
        'ATTENDEE;CN="'.$to_name.'";ROLE=REQ-PARTICIPANT;RSVP=TRUE:MAILTO:'.$to_address. "'r'n" .
        'LAST-MODIFIED:' . date("Ymd'TGis") . "'r'n" .
        'UID:'.date("Ymd'TGis", strtotime($startTime)).rand()."@".$domain."'r'n" .
        'DTSTAMP:'.date("Ymd'TGis"). "'r'n" .
        'DTSTART;TZID="'.date_default_timezone_get().'":'.date("Ymd", strtotime($startTime))."T".date("His", strtotime($startTime)). "'r'n" .
        'DTEND;TZID="'.date_default_timezone_get().'":'.date("Ymd", strtotime($endTime))."T".date("His", strtotime($endTime)). "'r'n" .
        'TRANSP:OPAQUE'. "'r'n" .
        'SEQUENCE:1'. "'r'n" .
        'SUMMARY:' . $subject . "'r'n" .
        'CLASS:PUBLIC'. "'r'n" .
        'PRIORITY:5'. "'r'n" .
        'BEGIN:VALARM' . "'r'n" .
        'TRIGGER:-PT15M' . "'r'n" .
        'ACTION:DISPLAY' . "'r'n" .
        'DESCRIPTION:Reminder' . "'r'n" .
        'END:VALARM' . "'r'n" .
        'END:VEVENT'. "'r'n" .
        'END:VCALENDAR'. "'r'n";