The Birdbath optical solution is widely used in AR glasses due to its low cost and high-quality imaging. In this article, we explore the structure of the BB optical scheme to understand why it is so popular.
The BirdBath module receives light from the light-emitting module, which usually consists of a high-brightness, high-resolution, small-sized silicon-based OLED screen located at the top. The light first passes through a lens, is amplified and zoomed in, and then shines onto a polarizing beam splitter, where it undergoes reflection at a 45-degree angle. The reflected light then goes to a curved mirror, which has both transmission and reflection properties. The light undergoes a series of processes here, and some of it is reflected back to the polarizing beam splitter. Finally, the light that passes through the polarizing beam splitter can be captured by the human eye. At this point, the light has completed its journey. The light emitted from the OLED passes through a series of optical treatments in the BB module, and the remaining effective light enters the eye to present the image we see.
Now, we can see the secret behind the low cost and high image quality of the BB solution. Its structure is simple, with low technical difficulty, and mostly made of plastic. The optical part is mainly responsible for magnifying the image. Additionally, the hollow structure ensures a relatively light weight. In my opinion, the BB optical solution is a cost-effective and efficient way to provide high-quality imaging for AR glasses. Its unique structure allows for effective manipulation of light, resulting in a clear and realistic virtual image.