Even if the employee never assigned rights to the firm, a court of law may find that the firm has the right to make use of the invention, and thus can not be sued by the employee for patent infringement.
This will allow the firm to attempt to capitalize on the value of the patent, as the firm is allowed to use the object of the patent in the routine operation of its business without royalty payments.
The shop right is a common law doctrine founded in equitable principles that allows an employer to use the employee's invention without payment to the employee if that invention was made using the employer's time, materials, facilities, or equipment.
Accordingly, this makes having only shop rights an undesirable position for most employers.
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