IN Brief:
- TDK’s meta-optic mirror is 150nm thick and provides approximately 80% visible-light transmission.
- Patterned nanoscale reflectors steer incident laser light towards the retina while allowing the optical element to remain flat.
- The present demonstration is monochrome, with TDK targeting full-colour operation and mass production within the next few years.
TDK has demonstrated a direct retinal projection display using a 150nm-thick meta-optic mirror that can be incorporated into an eyeglass lens while maintaining approximately 80% visible-light transmission.
The optical surface uses nanoscale reflectors arranged so that the direction of reflected laser light changes according to position across the lens. That patterned structure replaces the curved mirror used in conventional direct retinal projection systems with a flat element thin enough to be embedded into the lens itself.
Direct retinal projection sends the display beam towards the wearer’s retina rather than creating an image on a conventional display panel positioned in front of the eye. Earlier implementations have required a curved mirror close to the eye to steer the light, adding visible optical hardware and making the glasses more difficult to package into an ordinary frame.
TDK’s meta-optic approach transfers that steering function into a planar nanoscale structure. Different regions of the surface reflect incoming light at different angles, allowing the flat mirror to produce the directional behaviour normally obtained from a curved optical component.
The 150nm structure is considerably thinner than the visible wavelengths being manipulated. Its optical behaviour comes from the geometry and placement of the nanoscale reflectors rather than from the bulk curvature of a lens or mirror, placing the device within the wider field of metasurface optics.
Transmission remains important because the mirror sits in the user’s line of sight. TDK reports approximately 80% visible-light transmission, allowing most ambient light to pass through while a smaller proportion of the display beam is directed towards the eye.
The company is also positioning the structure around semiconductor-style manufacturing methods. Patterning optical behaviour through nanoscale surface features creates a route towards lithographic production rather than relying entirely on individually shaped bulk optical elements.
That process compatibility does not remove the manufacturing difficulty. The reflector geometry has to remain accurate across the active area, while surface defects, dimensional variation, layer uniformity, alignment, and contamination can alter the optical response. A lens-scale device also has to survive handling and integration into a wearable optical assembly.
The current demonstration operates in monochrome. TDK plans to develop full-colour capability by combining the mirror with other optical technologies already under development, including an ultra-compact full-colour laser module and visible-light laser control circuitry capable of supporting resolutions up to 4K.
The company is working with QD Laser on the wider retinal-projection platform. QD Laser contributes retinal projection technology and associated intellectual property, while TDK is developing laser modules, control electronics, meta-optic mirrors, and other parts of the optical engine.
The architecture also changes how display privacy appears at optical level. In a retinal projection system, the image is directed into the wearer’s eye rather than being formed on a panel visible from outside, reducing the image leakage that can occur when another person looks towards the glasses.
Waveguide displays take a different approach by carrying light through the lens before directing it towards the eye. They remain a major route for augmented-reality glasses, but their optical stacks can require several coupling and propagation structures. TDK is developing the meta-optic mirror as an alternative component architecture rather than presenting it as a direct replacement for every waveguide system.
The demonstration combines the flat mirror with a working direct retinal projection optical path, moving the development beyond an isolated metasurface sample. TDK plans to show the prototype publicly at CEATEC in October and electronica in November.
No production yield, field-of-view figure, eye-box dimension, display brightness, optical efficiency, or unit cost has yet been published. Those parameters will become central when the company moves from a working monochrome prototype towards full-colour operation and manufacturing.
TDK is targeting mass production within the next few years rather than announcing immediate product availability. The 150nm mirror establishes the optical concept and manufacturing direction; the remaining work lies in colour operation, optical-engine integration, calibration, production consistency, and the economics of manufacturing the nanoscale surface over lens-sized areas.
