Medical fluid injection device with fill indicator

An injection device comprising:

• a. a disc-shaped housing including a top surface, a bottom surface, a dispensing port positioned in the bottom surface, an arcuate window and a fluid fill indicator in an arcuate arrangement on the arcuate window, wherein the bottom surface is configured to be placed against a user's skin;
• b. an arcuately expandable member contained within said disc-shaped housing configured to hold a volume of liquid, said expandable member including an elastomeric bladder that is selectively in communication with the dispensing port, has a distal end, is elongated and is configured to expand arcuately when filled with the volume of liquid and hold the volume of liquid under pressure with an elastic force in a wall of the elastomeric bladder so as to provide pressure to expel the liquid from the elastomeric bladder through the dispensing port as the elastomeric bladder contracts;
• C. an internal indicator connected to the distal end of the elastomeric bladder, said internal indicator positioned within the disc-shaped housing and configured to move along an arcuate path adjacent to and visible through the arcuate window as the elastomeric bladder expands and contracts;
• d. wherein the fluid fill indicator includes an arcuate droplet icon positioned on the arcuate window of the disc-shaped housing and having an enlarged head portion and a tapered tail portion, said arcuate droplet icon being more opaque than the arcuate window and oriented so that the internal indicator moves in a first direction from the tapered tail portion towards the enlarged head portion as the elastomeric bladder expands and the internal indicator moves in a second direction from the head portion and towards the tail portion, and opposite the first direction, as the elastomeric bladder contracts.