What is inside Google Glass?

Side Touchpad

Removing the casing exposed a few parts, including the separate touchpad module on the right side of the unit. When a Glass users looks like they are pensively tapping their temple, they are interacting with this sensor. The touchpad is a full custom module made by Synaptics, and is driven by a Synaptics T1320A touchpad controller.

Main CPU Board

The main logic board was now exposed. The inwards-facing side holds an RF module, some small connectors and support ICs, and copper noting that this is "a GOOGLE [X] production".

This board was stuck to a thermal pad with lots of paste. After removing it and cleaning off the pink thermal compound, we revealed the core chips powering Glass: a TI OMAP4430, 16GB of SanDisk flash, an Elpida mobile DRAM chip. This board also holds RF devices, including a SiRFstarIV GSD4e GPS engine and an Bluetooth/WiFi module marked as WM-BN-BM-04-a and a data matrix which decodes to "85015340010112111400118159". A flex PCB and an RF cable, anchored with some metal tabs and a U.FL connector, trailed from this board to the behind-the-ear pod.
Some text in the copper on this board reads >9K!   It's over 9000!

Behind-Ear Module

To keep the unit's weight distributed more evenly, Glass keeps its battery in a rounded bit behind the wearer's ear. We stripped this area open, again applying destructive force to tear the plastic.
The single-cell Lithium Polymer battery sits at the end of the flexprint PCB and is marked as having a capacity of 2.1 Wh (roughly 570 mAh). It is not user-replaceable, not even a little bit.

Speaker

Just forward of the battery pod is a bone conduction speaker, which seems to double as a tactile switch.

Display Assembly

Another flex PCB, this one much more intricate, connects the main logic board to an assembly containing the display, camera, and some other sensors. It wraps around and through the frame holding those components. We gently pulled it off its connectors and extricated it.

The flexprint PCB holds Glass' inertial sensor, an InvenSense MPU-9150. Also included is what seems to be a Wolfson WM7231 MEMS microphone. There is an additional identical chip on the main logic board, suggesting that Glass may use a dual microphone noise-cancellation system.

Display

The Glass display is very small. It is adhered to the inside of the internal frame with light glue around the edge of the display board. We scraped off the glue with a dental pick and removed the board.
For scale, it is shown pictured on top of a US dime. With a native resolution of 640x360, the pixels are roughly 1/8th the physical width of those on the iPhone 5's retina display.

Optics

Glass uses a folded light pathway consisting of only a small handful of optical elements. Collectively they make the display's image appear to float a few feet from your face, in the top right corner of your vision. Steve Mann expands upon these optical strategies in much more detail and describes some additional challenges.

In the final photo, you can see this optical pathway at work when the display is removed.

Camera

The Glass camera seems to be of typical smartphone-level size and format. It is not coaxially aligned with the wearer's eye. The camera and display appear to talk to the CPU independently, with no direct connection between each other.

  Source: http://www.catwig.com/google-glass-teardown/