Silicon Ball Lens

Infrared transmission
Silicon commonly provides useful transmission from approximately 1.2 to 7.0 µm, depending on material grade, purity, doping, thickness and operating conditions. This makes silicon particularly relevant to near-infrared and mid-wave infrared optical systems.
The required operating wavelength should always be provided during quotation so that the correct material grade and coating can be evaluated.

High refractive index
Silicon has a refractive index of approximately 3.4 in the infrared. The high index allows a small spherical component to provide substantial optical power, supporting compact focusing and coupling arrangements.
Because refractive index changes with wavelength and temperature, the customer should provide the design wavelength when focal performance is critical.

Low density
Silicon has a typical density of approximately 2.329 g/cm³. It is considerably lighter than some alternative infrared optical materials, which can be beneficial in miniature, portable, airborne and weight-sensitive systems.

Mechanical durability
Silicon is a hard and durable material. Its mechanical properties make it suitable for optical components that must retain their form and performance during handling, assembly and operation in demanding environments.

Thermal stability
Silicon offers good thermal stability and thermal conductivity. These characteristics can help an optical component manage temperature variation and maintain dimensional stability in industrial and infrared applications.

Compact spherical geometry
A complete ball lens provides a compact optical form with rotational symmetry. The component can be integrated into small housings, sensor assemblies, optical packages and miniature infrared systems where available space is limited.

1. Silicon material and crystal properties
The optical performance of a crystalline silicon ball lens begins with the raw material. Customers can specify:

Material selection should be based on the operating wavelength, optical loss, environmental conditions and system-level requirements.

2. Ball diameter and dimensional tolerance
Industrial Technologies manufactures silicon balls from 0.30 mm to 3.0 mm in diameter, with a standard tolerance of ±0.0025 mm.
Customers may also specify:

Tighter or special dimensional requirements are evaluated according to the ball diameter, material, quantity and measurement method.

3. Optical performance
Where optical performance is critical, the enquiry should identify:

These details help determine whether the proposed silicon grade, ball diameter and coating are appropriate for the optical system.

4. Surface quality and polish
Surface requirements can be defined using the customer’s preferred inspection standard. Available requirements may include:

Our standard visual capability provides no visible scratch or dig at 50× magnification, depending on the silicon ball diameter. Where a formal scratch-dig or surface-roughness value is required, it should be included in the enquiry or drawing.

5. Optical coating
Silicon has a high refractive index and therefore produces significant reflection when used without an optical coating. A wavelength-specific anti-reflective coating can reduce reflection and improve transmission through the silicon ball lens.
Customers can specify:

Depending on the coating design, wavelength and silicon material, AR-coated silicon ball lenses can provide substantially higher transmission than uncoated components. Coating performance is confirmed for the agreed wavelength band rather than stated as one universal value.
[Learn more about our AR coated ball lens capability.]

6. Inspection and documentation
The required inspection level can be selected according to the application and purchase specification.
Available inspection and documentation requirements may include:

Every silicon ball lens is inspected for size, dimensional accuracy, polish level and cleanliness before delivery.

7. Packaging
Silicon ball lenses can be packed according to the customer’s assembly, handling and automation requirements.
Packaging options may include:

The correct packaging method should be selected according to ball diameter, quantity, coating, handling sensitivity and the customer’s production process.

Infrared sensors and detectors
A silicon ball lens can collect incoming infrared energy and direct it toward a miniature detector. Ball diameter, working distance, coating and alignment requirements can be selected around the detector size and operating wavelength.

Mid-wave infrared optical systems
Silicon is especially relevant to designs operating within the material’s useful near- and mid-infrared transmission region. Applications may include compact sensing, monitoring, detection and imaging assemblies.

Laser focusing and collimation
The high refractive index of silicon allows a small ball lens to provide strong focusing power. A custom lens may be designed to focus or collimate an infrared laser beam where compact dimensions are required.

Source-to-detector coupling
Silicon ball lenses may be integrated between an infrared source and detector to improve light collection or direct energy toward the active area of the receiving component.

Fibre-to-detector and detector-to-fibre coupling
Where the selected fibre, source and detector operate within the appropriate wavelength range, a silicon ball lens can be evaluated for coupling light between components.

Spectroscopy and gas sensing
Infrared spectroscopy and gas-analysis systems often require efficient control of light at specific absorption wavelengths. A custom silicon ball lens can be manufactured according to the operating band, source geometry and detector arrangement.

Optoelectronic packages
The compact spherical form can be integrated into miniature optical and optoelectronic packages where available space is restricted and repeatable bulk production is required.

Aerospace and industrial sensing
Silicon’s relatively low density, hardness and thermal properties can make it useful for compact sensing systems exposed to demanding operating conditions.

Raw-material review
Incoming silicon material is checked against the agreed material specification before manufacturing. The raw-material requirement may include grade, purity, crystal orientation, resistivity, doping, traceability or a customer-approved source.

Precision cutting
Silicon raw material is cut into controlled preforms using precision equipment. Accurate initial sizing supports material utilization and dimensional consistency during later processing.

Sphere generation and grinding
The prepared silicon pieces are processed into spherical form. Controlled grinding stages progressively develop the required ball diameter and spherical geometry.

Precision polishing
The silicon balls are polished to achieve the agreed surface condition, polish quality and visual acceptance standard.

Cleaning
Care is maintained throughout processing, including ultrasonic cleaning where appropriate. Finished products undergo final cleaning in a controlled environment.

Inspection
Every silicon ball lens is checked for Size, Dimensional accuracy, Polish level, Surface appearance and Cleanliness.
Inspection is performed according to the approved specification and agreed measurement method.

Cleanroom packing
Finished silicon ball lenses are cleaned and packed in a Class 100 cleanroom area. Packaging is selected according to the ball diameter, coating condition, quantity and customer handling requirements.

Prototype and development samples
Initial samples can be manufactured for optical evaluation, coating trials, assembly testing or design validation.

Qualification lots
Once the initial design has been reviewed, a controlled qualification quantity can be produced using the proposed material, process, coating and inspection method.

Bulk production
After specification approval, the process can be scaled for repeat bulk manufacturing. Production planning can include agreed lot sizes, inspection frequency, packaging and delivery schedules.

Repeat-order consistency
The approved drawing, material requirement, inspection criteria and packaging instructions form the basis for repeat orders.

Custom manufacturing rather than fixed catalogue supply
We manufacture silicon ball lenses according to the customer’s drawing, optical system and commercial requirement instead of restricting the buyer to a small set of standard configurations.

Experience in precision ball-lens manufacturing
Industrial Technologies specializes in precision balls, ball lenses and hemispherical components made from optical glasses, synthetic materials and single-crystal materials.

Swiss technology and precision equipment
Our manufacturing facility uses Swiss machines and precision measuring instruments to support repeatable ball-lens manufacturing.

In-house manufacturing control
Core ball-lens operations, from raw-material preparation to finishing, inspection, cleaning and packing, are managed through controlled manufacturing processes.

Prototype-to-volume support
Customers can begin with development samples, proceed to qualification and then scale the approved specification to bulk production.

Overall capacity exceeding five million pieces per month
Our established manufacturing infrastructure supports high-volume and repeat-order requirements.

International supply experience
More than 95% of the company’s overall sales are supplied to international markets, including customers in the USA, Europe, Japan, China and Vietnam.

Class 100 cleaning and packing
Finished silicon ball lenses are cleaned and packed in a controlled Class 100 cleanroom area.

Packaging for manual or automated assembly
Products can be supplied in waffle trays, clean vials or customized packaging suitable for the customer’s handling and assembly process.

What is a silicon ball lens?
A silicon ball lens is a complete spherical optical component manufactured from silicon. It can collect, focus, collimate or redirect infrared radiation within a compact optical assembly.

Do you manufacture crystalline silicon ball lenses?
Yes. We manufacture custom crystalline silicon ball lenses according to the customer’s material, diameter, surface, coating and inspection requirements. The customer may specify monocrystalline, single-crystal or another approved silicon grade.

What silicon ball lens diameters are available?
Our established silicon ball manufacturing range is 0.30 mm to 3.0 mm. Special dimensional requirements can be evaluated according to the drawing, material and order quantity.

What diameter tolerance can you provide?
Our standard silicon ball lens diameter tolerance is ±0.0025 mm. Tighter or specialized tolerances can be reviewed based on diameter, silicon material, measurement method and production quantity.

Can I specify silicon purity and crystal orientation?
Yes. Silicon purity, crystal orientation, crystal-growth method, doping and resistivity can be selected according to the customer’s requirements and raw-material availability.

Can you manufacture monocrystalline silicon ball lenses?
Monocrystalline or single-crystal silicon can be used when specified by the customer. Please provide the required grade, purity, orientation, doping and resistivity during the enquiry.

Can you manufacture from customer-supplied silicon?
Customer-supplied material can be evaluated. The material size, condition, grade, quantity, certificate and processing suitability must be reviewed before acceptance.

Are AR-coated silicon ball lenses available?
Yes. Silicon ball lenses can be supplied uncoated or with a custom anti-reflective coating designed for the required wavelength or wavelength band.

Why is an AR coating recommended for silicon?
Silicon has a high refractive index, which creates significant reflection at an uncoated surface. An appropriate AR coating can reduce reflection and improve transmission within the selected wavelength band.

What is the operating wavelength range of a silicon ball lens?
Silicon commonly provides useful infrared transmission from approximately 1.2 to 7.0 µm, although actual performance depends on silicon grade, purity, doping, resistivity, temperature and component geometry.

Why is an AR coating recommended for silicon?
Silicon has a high refractive index, which creates significant reflection at an uncoated surface. An appropriate AR coating can reduce reflection and improve transmission within the selected wavelength band.

Is a silicon ball lens suitable for visible light?
Silicon ball lenses are normally selected for infrared rather than visible-light applications. The operating wavelength must be provided before material suitability can be confirmed.

Is silicon suitable for 8–14 µm LWIR applications?
Silicon is generally not the first choice for conventional 8–14 µm LWIR systems because absorption increases outside its principal useful infrared range. Another infrared material may be more appropriate for such applications.

Can you manufacture silicon ball lenses according to our drawing?
Yes. We manufacture custom silicon ball lenses according to customer drawings, material requirements, dimensional tolerances, optical specifications and inspection standards.

Do you support prototype quantities?
Yes. Prototype and qualification quantities can be produced before the specification is released for bulk manufacturing.

Can you supply silicon ball lenses in bulk?
Yes. Industrial Technologies is structured for bulk and repeat-order manufacturing. Production quantities, lot sizes and delivery schedules are confirmed after technical review.

How are silicon ball lenses inspected?
Every silicon ball lens is checked for size, dimensional accuracy, polish level and cleanliness. Additional dimensional, surface, coating or optical inspection can be included according to the approved requirement.

What surface quality is available?
Our visual capability provides no visible scratch or dig at 50× magnification, depending on the diameter. A customer-defined scratch-dig or surface-roughness specification can also be evaluated.

How are the products cleaned and packed?
Finished silicon ball lenses are cleaned and packed in a Class 100 cleanroom area. Packaging options include waffle trays, clean vials and customer-defined formats.

What should I send for a quotation?
Send the diameter, tolerance, quantity, operating wavelength, silicon material requirement, coating, surface specification, packaging requirement and technical drawing. Where some parameters are unknown, include the application so they can be reviewed.