IR Mirror or a dielectric mirror for Projection & Display? A Selection Note

Optical designers sometimes treat mirrors as simple parts, yet in Projection & Display the mirror decides beam direction, loss budget and even image contrast. The IR…

Optical designers sometimes treat mirrors as simple parts, yet in Projection & Display the mirror decides beam direction, loss budget and even image contrast. The IR Mirror is a quietly critical component whose details repay careful attention.

At its core, the IR Mirror is a silicon, germanium or ZnSe element carrying a gold or dielectric for the infrared. That stack is engineered to return incident light efficiently over 700 nm – 10.6 µm, giving designers a predictable, low-loss way to steer a beam where they need it.

The working principle is the law of reflection applied to a coated plane. Mount the IR Mirror at 45° and a beam turns 90°; stack several and you fold a long path into a short box. That simplicity is why mirrors remain the fastest way to route light in Projection & Display.

The gold or dielectric for the infrared is where performance is won or lost. Deposited by vacuum processes, it is tuned so the reflected wave adds constructively across 700 nm – 10.6 µm, reaching > 98%. Getting the layer thickness right is a precision task: a few nanometers off and the reflectivity curve shifts.

Substrate choice for a IR Mirror is a trade between optical grade and budget. silicon, germanium or ZnSe is a common pick because it can be cut and polished to λ/4 flatness and a 40-20 surface, which is plenty for the reflection quality most Projection & Display systems require.

Typical specs worth putting on a drawing: surface flatness λ/4, surface quality 40-20 (scratch-dig), substrate silicon, germanium or ZnSe, thickness 1–6 mm, and reflectivity > 98% over 700 nm – 10.6 µm. Stating these up front saves rounds of sampling later. Our full technical specifications and standard sizes list the tolerances we hold routinely.

In Projection & Display, the IR Mirror usually appears wherever routing and combining light engines in compact housings. Designers value it because it keeps the beam path predictable and the loss budget small, which translates directly into a more stable instrument. The applications overview maps where each industry places it.

Choosing among options

Within the mirror family, the IR Mirror trades some peak reflectance for bandwidth and price. If Projection & Display demands the very highest reflectivity at one wavelength, a dielectric part wins; if it needs > 98% across 700 nm – 10.6 µm at sensible cost, the IR Mirror with its gold or dielectric for the infrared is the pragmatic choice.

Selecting a IR Mirror for Projection & Display starts with the wavelength and angle of incidence, then the acceptable loss. Match the gold or dielectric for the infrared to 700 nm – 10.6 µm, confirm > 98%, and make sure the silicon, germanium or ZnSe and 1–6 mm fit the mount you already have. The spec and size tables make that comparison quick.

Mirrors reward careful handling. Hold a IR Mirror by the edges, keep the coated face away from fingers and aerosols, and clean only with approved optics tissue and solvent when truly needed. Store it in its packaging, coated face protected, and it will hold > 98% for years.

Our production of a IR Mirror follows a simple, repeatable route: laser-cut the silicon, germanium or ZnSe to ±0.01 mm, smooth the edges, deposit the gold or dielectric for the infrared, and inspect to λ/4 / 40-20. Thickness options span 1–6 mm, and the same Hangzhou line that builds first-surface mirrors also runs windows, substrates and custom coatings.

Think of the IR Mirror as a precisely made silicon, germanium or ZnSe plate whose working surface is a gold or dielectric for the infrared. The result is > 98% reflection across 700 nm – 10.6 µm, which is exactly what most Projection & Display builders are looking for.

The IR Mirror is not exclusive to Projection & Display. Universities, service centers and R&D groups use it wherever a beam must turn, which makes a flexible, customizable part a quiet workhorse across the optics world.

Coating a IR Mirror means laying down a gold or dielectric for the infrared whose optical thickness is controlled to a fraction of a wavelength. Done well, the part holds > 98% over 700 nm – 10.6 µm; done carelessly, it drifts and the system loses light it cannot afford to lose.

Mounting notes

A IR Mirror is only as good as its mount. Use edge contact rather than clamping the face, avoid over-tightening that bends the silicon, germanium or ZnSe and degrades λ/4, and keep the coated side clear of adhesive. In Projection & Display a kinematically supported mirror stays aligned through thermal cycles and shipping.

Beyond Projection & Display, the same IR Mirror shows up in laboratories, teaching setups and OEM builds where routing and combining light engines in compact housings. Its value is generality: one well-made part serves many breadboards, which is why stocking a few standard sizes pays off.

A IR Mirror starts as a silicon, germanium or ZnSe blank. We hold it to λ/4 flatness and 40-20 surface quality, then apply the gold or dielectric for the infrared. The substrate never sees the beam directly, but its figure sets the limit on how straight the reflected wavefront stays.

Most of the engineering in a IR Mirror lives in its gold or dielectric for the infrared. The stack is designed for 700 nm – 10.6 µm and delivers > 98%, and its environmental protection layer keeps the metal from tarnishing so the mirror keeps working year after year.

When you specify a IR Mirror, the numbers that matter are flatness λ/4, finish 40-20, and the reflectance > 98% across 700 nm – 10.6 µm. Thickness 1–6 mm is mostly about handling and mount compatibility, but it still belongs on the print. The specification table covers the common configurations.

A IR Mirror is an optical component built so that reflection happens at the coated front face rather than through a substrate. With a gold or dielectric for the infrared on a silicon, germanium or ZnSe base, the part delivers > 98% reflectivity across 700 nm – 10.6 µm while keeping the useful aperture clean and ghost-free.

A IR Mirror starts as a silicon, germanium or ZnSe blank. We hold it to λ/4 flatness and 40-20 surface quality, then apply the gold or dielectric for the infrared. The substrate never sees the beam directly, but its figure sets the limit on how straight the reflected wavefront stays.

Typical specs worth putting on a drawing: surface flatness λ/4, surface quality 40-20 (scratch-dig), substrate silicon, germanium or ZnSe, thickness 1–6 mm, and reflectivity > 98% over 700 nm – 10.6 µm. Stating these up front saves rounds of sampling later. Our full technical specifications and standard sizes list the tolerances we hold routinely.

In short

For Projection & Display, the IR Mirror is less a commodity than a tuned component. Specify the band (700 nm – 10.6 µm), the reflectivity (> 98%) and the figure (λ/4), and you will spend less time debugging light you cannot see. That is the whole game. Where your application sits among the sectors we serve changes the details, not the method.