Procurement Report: Plano-Convex Singlet Lenses

1. Technical Specifications and Performance Metrics

The procurement of convex lenses, specifically Plano-Convex (PCX) singlets, requires precise alignment of optical parameters with application requirements. Based on industry standards and available product data, the following specifications define the core performance metrics for this category.

• Geometry & Dimensions:

  • Diameter (D): Standard stock sizes range from Ø1 mm to Ø150 mm, with common catalog sizes including Ø12.7 mm (0.5"), Ø25.4 mm (1"), and Ø50 mm.
  • Effective Focal Length (EFL): Ranges from f/1.4 to f/16. Specific catalog examples show focal lengths of 15.0 mm, 20.0 mm, 30.0 mm, extending up to 200.0 mm.
  • Edge Thickness (ET): Typically 2.0 mm for standard singlets, though this varies based on focal length and diameter to maintain structural integrity.
  • Center Thickness (CT): Varies inversely with focal length; for a 12.7 mm diameter lens, CT ranges from 3.39 mm (f=30mm) to 5.42 mm (f=15mm).

• Material Selection:

  • Visible/Near-IR: BK7 (Borosilicate Crown Glass) is the standard for visible to near-infrared applications.
  • UV/High Power: Fused Silica or Calcium Fluoride (CaF2) for superior transmission in UV bands and high laser power handling.
  • Mid-to-Far IR: Silicon (Si) for 1200–7000 nm and Germanium (Ge) for 2000–12000 nm.

• Coating & Transmission:

  • AR Coating: Standard bands cover 400–700 nm (Visible) or specific laser lines (e.g., 1064 nm).
  • Transmission: High-transmission coatings typically achieve >98% per surface in the design band.

Procurement Recommendation: Select Plano-Convex geometry for focusing collimated beams or collimating point sources. Avoid using the curved surface for collimation to minimize spherical aberration. When specifying, explicitly state the EFL and Diameter first, followed by the Material (e.g., BK7 for visible, Si for IR) and the AR Coating band to ensure optimal transmission for your specific wavelength.

2. Industry Compliance and Quality Assurance

While specific named certifications (e.g., ISO 9001) were not explicitly detailed in the source data, industry-standard compliance for optical components relies on rigorous surface quality and dimensional tolerances.

• Surface Quality: Standard singlets typically adhere to 40-20 or 60-40 scratch-dig standards. High-end applications may require 10-5.
• Dimensional Tolerances:
  • Diameter: ±0.1 mm to ±0.2 mm.
  • Focal Length: ±1% to ±2% (typical for stock items).
  • Centering: <3 arcminutes for precision singlets.
• Material Homogeneity:
  • BK7/Fused Silica: Homogeneity class typically Δn < 2×10⁻⁶.
  • IR Materials (Si/Ge): Require specific purity grades to minimize absorption in the target IR band.

Procurement Recommendation: Request a Certificate of Conformance (CoC) or Test Report for every batch, specifically verifying the Focal Length and Surface Quality against the datasheet. For high-power laser applications (e.g., 1064 nm), explicitly request Laser Induced Damage Threshold (LIDT) data, as standard BK7 may fail under high fluence compared to fused silica.

3. Cost Efficiency and Integration Capabilities

• Cost Drivers:

  • Material: BK7 is the most cost-effective for visible light. CaF2, Si, and Ge carry a significant premium due to material scarcity and machining difficulty.
  • Coating: Single-band AR coatings are standard; broadband or multi-wavelength coatings increase cost by 20–40%.
  • Size: Larger diameters (>50 mm) and longer focal lengths generally increase unit cost non-linearly due to material waste and polishing time.

• Integration:

  • Mounting: Standard lenses (e.g., Ø25.4 mm) are designed for standard Ø1" lens tubes or SM1 threads.
  • Assembly: Most catalog items are "Single" assembly types, meaning they are unmounted singlets requiring user integration.
  • Compatibility: Ensure the Edge Thickness (ET) allows for the intended mounting ring without clipping the beam.

Procurement Recommendation: For volume procurement, prioritize standardized diameters (Ø12.7 mm, Ø25.4 mm) and common focal lengths to leverage economies of scale. If integrating into a tight mechanical envelope, verify the Center Thickness (CT) and Edge Thickness (ET) to ensure the lens fits within the designated housing without requiring custom machining.

4. Typical Use Cases

Based on the material and wavelength data, these lenses are deployed in the following scenarios:

• Visible Light Optics (BK7, 400–700 nm):
  • Applications: Camera lenses, projectors, beam expanders, and general imaging systems.
  • Scenario: Collimating light from an LED or focusing a laser diode output.
• High-Power Laser Systems (1064 nm, BK7/Fused Silica):
  • Applications: Laser cutting, welding, and material processing.
  • Scenario: Focusing a 1064 nm Nd:YAG laser beam to a small spot size.
• Infrared Spectroscopy & Thermal Imaging (Si/Ge, 1200–12000 nm):
  • Applications: Gas analysis, thermal cameras, and night vision systems.
  • Scenario: Focusing mid-IR radiation from a blackbody source onto a detector.
• UV Lithography & Fluorescence (CaF2, 170–8000 nm):
  • Applications: UV curing, fluorescence microscopy.
  • Scenario: High-transmission focusing in deep UV where glass would absorb light.

Procurement Recommendation: Match the Material strictly to the Wavelength. Do not use BK7 for wavelengths >2500 nm (absorption occurs) or <350 nm (transmission drops). For IR applications, explicitly specify Silicon for 1.2–7 µm and Germanium for 2–12 µm.

5. Long-Term Planning Considerations

• Market Trends:

  • Miniaturization: Increasing demand for smaller diameter lenses (Ø1–10 mm) for portable medical devices and smartphone cameras.
  • Laser Power Scaling: As laser power increases, there is a shift from standard BK7 to Fused Silica or CaF2 to prevent thermal lensing and damage.
  • IR Expansion: Growth in autonomous vehicles (LiDAR) and thermal imaging is driving demand for Silicon and Germanium optics.

• Supply Chain Resilience:

  • Lead Times: Standard BK7 lenses typically have short lead times (2–4 weeks). Specialty materials like CaF2 or Ge may require 8–12 weeks due to raw material sourcing.
  • MOQ: Single-unit purchases are common for prototyping. Bulk orders (MOQ 10–50 units) often yield 10–15% discounts.

Procurement Recommendation: For long-term projects, secure framework agreements for specialty materials (Si/Ge) to mitigate lead time risks. Plan for a 15% buffer in inventory for high-demand standard sizes (Ø25.4 mm, f=50mm) to avoid production stoppages. Monitor the shift toward fused silica for laser applications to future-proof your optical designs against higher power densities.

6. Special Product Recommendations

The following table compares specific product configurations based on the search context to guide buyer selection.

| Product Type | Best-Fit Buyer | Key Specs | Risk Check | Procurement Advice | | :--- | :--- | :--- | :--- :--- | | BK7 Plano-Convex | General Optics / Laser (1064nm) | D: 12.7–50mm, f: 15–30mm, AR: 1064nm | Check LIDT for high-power lasers | Standard choice; verify coating for specific laser line. | | CaF2 Plano-Convex | UV Systems / High-Precision | D: 25.4–200mm, f: 100–200mm, Band: 170–8000nm | Fragility; high cost | Essential for UV; handle with care, verify coating durability. | | Silicon (Si) Plano-Convex | IR Spectroscopy / Thermal | D: 25–200mm, f: 25–200mm, Band: 1200–7000nm | Heavy; requires IR mount | Ideal for 1.5–5 µm; ensure mechanical support for weight. | | Germanium (Ge) Plano-Convex | Thermal Imaging / Far-IR | D: 25–200mm, f: 25–200mm, Band: 2000–12000nm | Soft material; expensive | Use for 8–12 µm; apply soft-handling protocols during assembly. |

Procurement Recommendation: Select BK7 for cost-sensitive visible/1064nm applications. Upgrade to CaF2 if operating below 350nm or requiring high thermal stability. For IR, strictly match Si to 1.2–7 µm and Ge to 2–12 µm. Always verify the Assembly type (Single vs. Mounted) to ensure compatibility with your existing mechanical design.

7. Frequently Asked Questions (FAQ)

Q1: What is the difference between a Plano-Convex and a Bi-Convex lens for my application? A: A Plano-Convex (PCX) lens is generally preferred for focusing collimated light or collimating a point source because it minimizes spherical aberration when oriented correctly (curved side toward the collimated beam). A Bi-Convex lens is better for imaging applications where the object and image distances are roughly equal.

Q2: Can I use a standard BK7 lens for a 1550 nm telecommunications laser? A: Yes, BK7 transmits well up to ~2.5 µm. However, ensure the AR coating is specifically designed for 1550 nm, as standard 400–700 nm coatings will reflect most of the light at this wavelength.

Q3: What are the typical lead times for Germanium lenses? A: Due to the specialized nature of Germanium material and coating, lead times typically range from 8 to 12 weeks, whereas standard BK7 lenses are often available in 2–4 weeks.

Q4: How do I determine the correct focal length for my setup? A: Use the lens equation ($1/f = 1/d_o + 1/d_i$). If you are collimating a source at a specific distance, the focal length should match that distance. If focusing a collimated beam to a spot, the focal length determines the spot size and working distance.

Q5: Is the "Single" assembly type suitable for my optical bench? A: "Single" refers to an unmounted lens. You will need to purchase a separate lens mount (e.g., Ø1" tube or SM1 thread) compatible with the lens diameter (e.g., Ø25.4 mm) to integrate it into your optical bench.

Q6: What is the minimum order quantity (MOQ) for custom focal lengths? A: For standard catalog sizes (e.g., f=50mm, Ø25.4mm), MOQ is often 1 unit. For custom focal lengths or non-standard diameters, MOQs typically start at 10–50 units depending on the manufacturer.

Q7: How do I handle Silicon or Germanium lenses to prevent damage? A: These materials are softer and more brittle than glass. Always handle them with powder-free nitrile gloves and use plastic or coated tweezers. Avoid touching the optical surfaces directly.

Q8: What is the typical surface quality standard for these lenses? A: Standard commercial lenses usually meet 40-20 or 60-40 scratch-dig specifications. For high-end imaging or laser applications, request 10-5 or better to minimize scattering and beam distortion.