Filter data with blanks

hello
i m using below code to filter my data

Sub FilterNamesOL()
UnProtect_OL_BC
Worksheets("OL BC").Range("OL_BC").AutoFilter _
Field:=11, Criteria1:=">=" & Worksheets("OL BC").Range("D6") _
, Operator:=xlAnd, Criteria2:="<=" & Worksheets("OL BC").Range("D6")
Range("E9").Select
Protect_OL_BC
End Sub

i want filter data with blanks cells

thanx