I'm driving a blue 7-segment LED display with a TI CD4026BE on a 3.3V circuit.
I cannot find any data sheet for the display part. It has a common cathode pin layout and it's marked FJ5161AB on the side and D5611 A/B on the bottom.
At first I tried putting some conservative resistor values, but then I noticed that the formula would give a Vf (LED drop) pretty close to Vcc. So I tried connecting the LEDs directly to the chip's outputs (3.28V) and the current consumption is 0.67mA per LED.
I know that blue LEDs can drop up to 3.3V. Is this current value low enough that I can get away with no series resistors?
Here's a couple pictures: