OID value: 1.2.840.1135188.8.131.52
The unstructuredName attribute type specifies the name or names of a subject as an unstructured ASCII string. The interpretation of unstructured names is intended to be specified by certificate issuers etc.; no particular interpretation is required. An unstructured-name attribute can have multiple attribute values. When comparing two unstructured names, case is irrelevant.
URL for further info: http://www.rsalabs.com/pkcs/pkcs-9/index.html
See also the OID Repository website reference for 1.2.840.1135184.108.40.206