How to clear cache when using hookDisplayProductButtons to create button on detail product page?

[phinq1910]

I am created a button on detail product page.
But, when I update .tpl file then F5/Ctr-F5, it is not change
 
So, how do I can clear cache for .tpl file (only it)?
 

public function hookDisplayProductButtons($params)
{
global $cookie ,$smarty;


//$smarty->clearCompiledTemplate('test_front_product_detail.tpl'); // can not change
$this->_clearCache('test_front_product_detail.tpl'); // can not change


return $this->display(__FILE__, 'test_front_product_detail.tpl');
}

 

Please help me.
 
Thanks you!

Edited May 7, 2016 by phinq1910 (see edit history)