PHPExcel CSV另存为unicode而不是CSV

I use the PHPExcel(); Function to export some CSV files.

My current problem is that the CSV is open by Excel fine but on "save as" the Content Type is Unicode Text not CSV

I save the export file on disk (no direct download) and added the setUseBOM true

$objPHPExcel = new PHPExcel();
// $objPHPExcel->getProperties() [...] for example reduced
// $DATA example: $DATA[0][0] = "A1", $DATA[1][0] = "A2" ...
$objPHPExcel->getActiveSheet()->fromArray($DATA, null, 'A1');

$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'CSV'); 
$objWriter->setUseBOM(true);
$objWriter->setDelimiter(';');
$objWriter->setEnclosure('');
$objWriter->setLineEnding("
");
$objWriter->setSheetIndex(0);

$objWriter->save($filename);

But on Excel and "save as" the Data Type ist "Unicode Text (*.txt)", thx for help!