If you contributed to conception of the ideas in any claims of the patent, you must be named as a (co-)inventor for a US patent to be valid. If you defined the problem but not the solution or if you implemented an inventive solution that somebody else specified then you must not be named.
If you feel that you should be named, you might want to gently and politely suggest that to your manager. If you can reach the attorney or agent who will or did file the patent application, you can mention it. They are ethically obligated to inquire and make sure that the correct inventors are named.
If you have evidence to prove that you should have been named as an inventor yet the company knowingly left you out, you have grounds to invalidate the patent later. If the company is licensing out the patent, you could approach the licensee. They might be happy to stop paying license fees for an invalid patent. However, doing so might make you quite unliked by some people.