how to write the content obtained using the method GetPdfText

[Anisha]

In the below code

Set oPDF=CreateObject("LearnQuickTest.ManipulatePDF")
Set FSO = CreateObject("Scripting.FileSystemObject")
detailvalue=oPDF.GetPdfText("D:\POC\sample.pdf")

detailvalue is a string but when i debug detailvalue is empty string. 
 
When i write 'detailvalue' into a text file its is getting written but not readable using QTP, but when i open text file manually i can see the content

Please advise how to  convert the oPDF.GetPdfText("D:\POC\sample.pdf") to a readable string.