Adding column in already created table in postgresql,make it lower

I have already created table .I want to add one more string column into it.

ALTER TABLE test."persons" 
ADD COLUMN RightName VARCHAR(150);

Column get added in table with name rightname.

Why this is so,why not RightName?Any thing I missed.
Do I need to specify length for varchar column.

>Solution :

Try:

ALTER TABLE test."persons" 
ADD COLUMN "RightName" VARCHAR(150);