The optical module is a key component for the mass production of Vision Pro, and the difficulty of film sticking/bonding limits production efficiency. In MR head display devices, the optical module is responsible for near eye focusing and expanding the field of view. It uses the principle of refraction of optical lenses to change the direction of light, focusing the micro display screen close to the human eye and enlarging the screen image size, allowing users to obtain a larger viewing angle. Vision Pro adopts a 3P Pancake three piece lens optical module. The core difficulty in preparing 3P Pancake lies in the curved surface bonding of the folded optical path composite optical film and the bonding assembly of the three lenses. During the curved film bonding process, attention should be paid to the impact of film damage and bonding defects on the optical performance and yield of the module. The lens assembly process must ensure the accuracy of the optical path. The production efficiency of 3P Pancake optical modules is one of the key factors for Vision Pro to expand its shipment scale. Efficient curved film coating equipment and high-precision AA (Active Alignment) equipment play a key role in improving efficiency and yield.

The manufacturing process of Vision Pro 3P Pancake optical module includes single lens production, optical film pasting, and three lens assembly. Vision Pro adopts 3P Pancake curved lens optical module, which effectively compresses the distance between the screen and the lens through the design of folding optical path, reduces the total length of the optical module, and lowers the weight and thickness of head display equipment. The 3P Pancake folding optical path scheme requires the bonding of optical films after the production of a single lens. From the display screen end to the human eye end, there are semi transparent and semi reflective films, quarter wave plates (QWP), and reflective polarizing films (RP), which are based on the principle of polarized light. They use the selective reflection and transmission characteristics of reflective polarizing films for different polarized light, and adjust the polarization shape with a 1/4 phase delay plate to achieve the back and forth reflection of light between the semi transparent and semi reflective mirror and the reflective polarizing film, and finally transmit it out of the reflective polarizing film. After the film is applied, the optical module assembly factory needs to use AA equipment to glue and assemble the three lenses according to the established optical path design to ensure the accuracy of the optical path.

The 3P Pancake curved film coating is difficult and time-consuming, and strict optical film bonding process is required for adhesive assembly and alignment. For multi-layer high-precision optical film bonding, issues such as accuracy, stray light, and optical axis alignment and focusing need to be considered. In addition, the Vision Pro optical module lens is spherical, requiring a more technically difficult curved film coating process. Curved surface pasting process processes the pre prepared plane film material into a specific two-dimensional curved surface through hot bending and stretching technology, which can be pasted on the surface of the lens, resulting in a larger field of view angle and better imaging quality. However, stretching and other processes will lead to orange peel and crack of the optical film, which is easy to wrinkle and warp the edges during the pasting process, affecting the optical performance and yield of the module. Moreover, the pasting of a single module takes a long time.

In terms of alignment bonding assembly, Pancake has high sensitivity to optical path accuracy and strict alignment requirements. Even slight angle differences can affect the final imaging effect. When assembling the lens, it is necessary to strictly follow the established optical path design.

The lens surface film sticking equipment changes the shape of the film material and adheres the film material. The AA bonding equipment is used for lens to lens adhesion. The lens surface film sticking equipment has multiple processes. According to the patent of GoerTek's curved workpiece film sticking equipment, its curved workpiece film sticking equipment includes a film sticking mechanism, a displacement mechanism, a carrier platform, a film pressing platform, and a film sticking platform. The flexible pressure head in the film sticking mechanism absorbs the film material, and the film pressing platform heats the film material and drives the flexible pressure head to adhere to the workpiece imitation component to obtain the desired shape of the film material. The formed film material is driven by the displacement mechanism to adhere to the curved workpiece, and the film material is processed into a shape that is compatible with the curved workpiece. During the bonding process, buckling and wrinkling can be avoided to a certain extent. High precision AA equipment plays a crucial role in the Pancake assembly process, mainly used for lens to lens bonding. At present, mainstream AA bonding equipment can adopt a human visual system design to achieve automatic grasping, alignment, optical axis correction, dispensing, detection, curing and other actions.

Risk Warning: Vision Pro Optical Module Solution Change, 3P Pancake Curved Film Coating Technology Change.