Angel Academe backed the wearable technology maker in a round led by Ros Singleton.
"Since we first met them, doppel has been through 2 sets of customer shipments and a manufacturing iteration, so has matured significantly as a business. The doppel team are open, enthusiastic, customer-focused and resilient and the product works with lots of positive stories of how it helps customers control their stress levels."
The funding round was led by Cambridge Enterprise with participation from Amadeus Capital Partners, Parkwalk Advisors, IQ Capital Partners and angel investors.
"The new Paragraf facility is a significant step towards realising the potential of graphene in commercially viable, scalable electronic devices, bringing the beneficial impacts of this wonder material to the world."
The seed round was backed by Startup Funding Club, the London Co-Investment Fund, and the British Robotics Seed Fund.
"Our digital realities platform fills a clear gap in the market for high-resolution output that is realistic and needs no further editing before being put into a VR or AR setting."
The investment will provide working capital to support the continued scale up of the company.
"Spectral Edge continues to pioneer in the imaging sector, with market opportunities across a broad range of sectors. We are proud to have Spectral Edge within our portfolio of deep tech companies, all developing leading-edge AI and generating strong IP."