I've been working on a project the past couple months or so and I am incorporating an lcd touch screen as an interface for it. The device is a small digital synthesizer. The problem I am having is that when I have the screen connected to the circuit, I notice that it produces a great deal of electrical noise on the power rail. This noise is bleeding into the audio amplifier section of my circuit and making its way into the output audio of the device. I have filtering on each individual block of my circuit and that has been good up to this point, but it doesn't seem to help this at all. I'm not sure how to go about solving this. The only thing I can think of is that I need to somehow isolate either the screen from the rest of the circuit or isolate the block that handles the audio signal. I'm not exactly sure how to go about this though.

The noise itself is a mix of a lower frequency hum and some high hiss. I assume this is caused by both the refresh rate of the screen plus the multiplexing of the LEDs. I don't have a schematic for the actual circuitry of the LCD screen as the manufacturer doesn't seem to provide one

I have some screenshots from my scope for the 5v rail with both the screen disconnected
[![enter image description here](https://i.stack.imgur.com/adxlk.png)](https://i.stack.imgur.com/adxlk.png)
and also connected to the circuit.
[![enter image description here](https://i.stack.imgur.com/OTzas.png)](https://i.stack.imgur.com/OTzas.png)

Here is a simplified schematic of the circuit I'm using. I know the power supply section of it could be better, but I'm still learning. Any help would be appreciated! :D
[![enter image description here](https://i.stack.imgur.com/AFc2J.png)](https://i.stack.imgur.com/AFc2J.png)