1. Transparent Conductivity on a Custom Glass Dome

Felix Glass supports custom glass dome projects incorporating an indium tin oxide (ITO) conductive layer. The dome provides the optical and mechanical interface; the coating adds an electrically conductive surface for a defined function such as resistive heating or charge dissipation.

Each project is reviewed around the drawing, operating spectrum, electrical targets and installation conditions. Curvature, coating accessibility and electrode placement are evaluated together before the specification is confirmed.

2. Custom Specification Overview

Numerical targets are confirmed for the selected material, geometry and coating stack. Flat-glass catalog values should not be treated as guaranteed specifications for a custom dome.

3. Glass Materials and Spectral Compatibility

Candidate substrates include suitable optical crown glass, borosilicate glass and fused silica. Selection depends on the wavelength band, optical quality, thermal exposure and forming or polishing requirements. Specify a manufacturer grade where material identity is mandatory.

Both substrate and ITO stack must transmit the operating wavelengths adequately. Visible transparency does not establish transmission at 905, 940 or 1550 nm, or in a thermal-imaging band. Provide the full source and detector bands for review.

4. Dome Geometry and Clear Aperture

Provide inner and outer surface definitions, opening diameter, overall height, flange dimensions and wall-thickness requirements. Define reference axes and mounting interfaces, and state whether optical aperture dimensions are projected or follow the curved surface.

Identify the viewing region separately from busbars, masked edges, sealing lands and adhesive zones. Specify image quality across the required field rather than only at the dome center. Coating and electrode placement must preserve the usable optical path.

5. ITO on Curved Surfaces

Conductive films can be deposited on suitable curved substrates, but thickness distribution and electrical uniformity depend on geometry and process access. Inner-surface access, steep curvature and edge regions require project-specific review.

Depositing ITO on an already formed dome is different from bending coated flat glass. Do not assume a film qualified on a flat sample will survive a later forming step or retain the same resistance after deformation. The proposed manufacturing sequence must be qualified for the actual part.

6. Sheet Resistance and Electrical Uniformity

Specify sheet resistance in ohms per square (Ω/□), including tolerance, measurement temperature and sampling positions. Sheet resistance describes the conductive film; it is not the same as the resistance measured between the installed terminals.

Terminal resistance also depends on current-path geometry, contact layout and contact resistance. The familiar rectangular-film relationship R = RₛL/W applies under its ideal planar geometry and electrode assumptions. It should not be applied to a dome by substituting its diameter for both dimensions.

Agree on a curved-surface measurement method and electrode-to-electrode checks. A flat witness coupon can support coating-process monitoring but does not by itself prove resistance uniformity over the dome.

7. Transmission, Reflection and Coating Appearance

Specify minimum or average transmission, wavelength interval, incidence conditions and the clear aperture. Identify whether performance is required through the complete dome or for an individual coated interface.

Conductivity and transmission must be balanced in the selected stack. ITO thickness, optical matching layers and substrate properties affect spectral response and reflected color. Request data for the relevant band rather than judging performance by visible appearance alone.

Where imaging is critical, include haze or scatter, wavefront or image-quality limits, and acceptable changes across the field of view.

8. Transparent Heating and Condensation Control

An ITO layer can act as a resistive heater when connected to a suitable electrical supply. A heating design can support condensation control when it maintains the relevant surface above the dew point under the specified environment.

Provide supply voltage, power limit, ambient range, humidity, airflow, warm-up target and maximum permissible surface temperature. Heating uniformity depends on electrode layout, heat loss through the mount and temperature-dependent electrical behavior.

De-icing is a separate load case requiring ice conditions and removal-time targets. A conductive dome alone is not a complete regulated heating assembly; controller, sensing, wiring and protection responsibilities must be defined.

9. Busbars, Contacts and Electrical Interfaces

Identify contact pads, busbars and lead attachment locations on the drawing. Specify contact resistance, mechanical attachment and environmental exposure requirements where applicable.

Electrode layout should control current distribution while avoiding obstruction of the optical aperture. A continuous conductive ring is not automatically an effective heater arrangement without a defined second electrode and current path.

Confirm whether the order covers only the coated dome, deposited contacts, attached leads or an assembled heater. Lead strain relief, insulation and sealing must be addressed at the agreed assembly level.

10. Additional Optical and Protective Treatments

AR or optical matching layers may be considered where compatible with the ITO electrical function. Protective layers can be reviewed for exposed surfaces, with contact regions left accessible as required.

Any additional layer can affect transmission, reflection, adhesion, resistance access or cleaning behavior. The complete stack must be evaluated on the chosen substrate. Do not assume that separately qualified coatings retain their specifications when combined.

Assign inner and outer faces explicitly. The best location for environmental protection may differ from the best location for electrical access or process uniformity.

11. Application Options

Sheet resistance alone does not establish electromagnetic shielding effectiveness. Any attenuation target must be verified for the installed enclosure and its interfaces.

12. Inspection and Qualification

Agree on optical, dimensional and electrical inspection before production. Typical review items include geometry, wall thickness, optical aperture, surface condition, spectral transmission, resistance mapping and terminal resistance where contacts are supplied.

For heated assemblies, specify the test fixture, power conditions, ambient environment and temperature-map acceptance limits. Include post-exposure optical and electrical measurements for relevant humidity, temperature-cycle or cleaning tests.

Reports should identify drawing revision, sample or lot, measurement conditions and whether data are from the finished dome or a witness coupon. Certification and specialized qualification requirements must be confirmed in the quotation.

13. Prototype, Packaging and Production Planning

Prototype evaluation is useful for checking resistance distribution, optical appearance, contact layout and mounted thermal behavior before fixing production requirements. Request separate prices for the development quantity and expected production batches.

Specify packaging that protects the coated face and prevents loads on electrical contacts. Include part labels, orientation identification and handling instructions as needed. Manufacturing schedule, delivery terms and report scope are confirmed for each order.

Before release, approve the substrate, coating stack, electrode layout and acceptance criteria, and establish how subsequent design or process changes will be reviewed.

14. Frequently Asked Questions

15. Request a Custom ITO Glass Dome Quote

Send your dome drawing and operating requirements to Felix Glass. Include prototype and production quantities, coated-face designation, clear aperture, transmission targets, electrical requirements and the requested delivery destination.

Dongguan Felix Glass Co., Ltd.
Email: james@felixglass.com