laravel5.2 provider注入自己的类

错误：FatalErrorException in BillingServerProvider.php line 27:
Class 'App\Providers\LoginAdmin' not found

ServerProvider.php：

public function register()

{
    $this->app->bind('Billing',function(){
        return new LoginAdmin();
    });
}

Login.php
<?php
namespace App\Billing;

class LoginAdmin{

public $name;
public $password;
public function __construct($name='',$password='')
{
    $this->name = $name;
    $this->password = $password;
}
public function Account(){
    if(isset($this->name)&&!empty($this->name)){
        return $this->name;
    }else{
        return $this->name = '';
    }
}

}
?>
控制器：

$login = app('Billing');
dd($login);