signal lcd_counter, next_lcd_counter : STD_LOGIC_VECTOR(19 downto 0) := CONV_STD_LOGIC_VECTOR(0,18);

and

assign_next_counter : process( clock , next_lcd_counter)
begin
	if( rising_edge( clock ) ) then
		lcd_counter <= next_lcd_counter;
	end if;
end process;
	
and
	
next_lcd_counter <= lcd_counter + 1;
	
and
	
next_lcd_counter <= CONV_STD_LOGIC_VECTOR(0,20);
	
etc etc etc.