I am writing an controller and VF component to email opportunitylineitemschedule details as an attachment. I am able to include schedule details to the attachment, but i am not able to include the opportunitylineitem's field in the same table. 

My requirement - for each line item schedule row, i would like to have one column populating the opportunitylineitem.Product_Name__c values. I am getting unknown property error 'String.Product_Name__c' if i try to add this field. 
my controller: 
public class emailtemplatev2{
    public emailtemplatev2() {    
    }
  List<OpportunityLineItemSchedule> revenue = new List<OpportunityLineItemSchedule>(); 
   public Id opportunityId {get;set;} 
   public List<OpportunityLineItemSchedule> getrevenue()
   { 
       revenue=[Select OpportunityLineItemId, CurrencyIsoCode, ScheduleDate,Revenue                           
                 from OpportunityLineItemSchedule where OpportunityLineItemId IN (Select ID from OpportunityLineItem 
                 where OpportunityId =:opportunityid )  ];
     return revenue;
        }  
}


VF Component: 
<apex:component controller="emailtemplatev2" access="global">
    
   
    <apex:attribute name="AcctId" type="Id" description="Id of the account" assignTo="{!opportunityId}"/>
    <table border = "2" cellspacing = "0" >
        <tr>
            <td>Product</td>
            <td>Forecast Period</td>
            <td>Currency</td>   
            <td>Amount</td> 
                         
        </tr>
        <apex:repeat value="{!revenue}" var="o">
        <tr>
            <td>{!o.OpportunityLineItemId.Product_Name__c}</td> //having issue in this line
            <td>   
            <apex:outputText value="{0,date,MMM, yyyy}">
            <apex:param value="{!o.ScheduleDate}" /> 
            </apex:outputText>
            </td>  
        
            <td>{!o.CurrencyIsoCode}</td>  
            <td>{!o.Revenue}</td> 
                        
        </tr>
        </apex:repeat>        
    </table>
</apex:component>