Loading Bar Help

Hi!

I would like to get some help with my loading bar. I want to slow it down so you really can see that it's loading. Now it pops up for like 1 second then dissapears. I know it depends on how heavy your scene is but is there any other way to slow it down?

The script:

 var ProgressBar : GameObject;
 var Text : GameObject;
 var Backgraund : GameObject;
 
 var LevelToLoad : String;
 private var loadProgress : int = 0;
 
 function Start ()
 {
     Backgraund.SetActive(false);
     Text.SetActive(false);
     ProgressBar.SetActive(false);
 }
 
 function Update ()
 {
     if(Input.GetKeyDown("space"))
     {
         StartCoroutine("DisplayLoadingScreen");
     }
 }
 
 function DisplayLoadingScreen(): IEnumerator
 {
     Backgraund.SetActive(true);
     Text.SetActive(true);
     ProgressBar.SetActive(true);
 
     ProgressBar.transform.localScale = new Vector3(loadProgress,ProgressBar.transform.localScale.y, ProgressBar.transform.localScale.z);
 
     Text.guiText.text= "Loading..." + loadProgress + "%";    
     
     var async : AsyncOperation = Application.LoadLevelAsync (LevelToLoad);
     while(!async.isDone)
     {
         loadProgress = async.progress * 100;    
         Text.guiText.text = "Loading..." + loadProgress + "%";    
         ProgressBar.transform.localScale = new Vector3(async.progress,ProgressBar.transform.localScale.y, ProgressBar.transform.localScale.z);    
         return;
     }
 }