SL12 Dot Grid Distortion target

PURPOSE

Dot grid array targets are used for evaluating the sharpness, distortion, alignment, and spatial calibration of imaging systems, including cameras, scanners, microscopes, and vision sensors. Their uniform dot distribution allows for consistent analysis of optical resolution, lens distortion, image warping, and geometric alignment. The integrated centre markers support automated recognition, angle correction, and registration tasks. These arrays are commonly used in industrial inspection, machine vision calibration, robotics, and metrology, but can be adapted to many other imaging and photonic applications where pattern repeatability and accurate geometry are required.

CONFIGURATION

• Material: Chrome on Transparent Soda Lime Glass, 1.5 mm thick, available as 3" (75 mm), 5" (125 mm), or 8" (200 mm)
• Material: Chrome on White Glass, 1.25 mm thick, available as 4" (100 mm) or 8" (200 mm)

PATTERN DESCRIPTION

Highly accurate dot grid arrays, where the pattern area is 25 mm smaller than the glass plate size.

Each array consists of uniformly spaced circular dots. For example, the 5 mm dot grid comprises 5 mm dots spaced at 10 mm pitch, while the 0.1 mm version uses 0.1 mm dots spaced at 0.2 mm pitch. Each pattern includes alignment markers in the form of donut shapes arranged in an L-configuration at the centre to support rotational referencing. Low-resolution PDF images of the patterns are available from the Download tab.

• SL12-1: 5 mm dot, 10 mm pitch
• SL12-2: 4 mm dot, 8 mm pitch
• SL12-3: 2 mm dot, 4 mm pitch
• SL12-4: 1 mm dot, 2 mm pitch
• SL12-5: 0.50 mm dot, 1 mm pitch
• SL12-6: 0.25 mm dot, 0.5 mm pitch
• SL12-7: 0.10 mm dot, 0.2 mm pitch
• Other configurations available on request

ACCURACY

Class 2: Dot size ±1.6 µm, overall pitch accuracy (corner to corner) ±8 µm

Class 3: Dot size ±0.8 µm, overall pitch accuracy ±4 µm

Class 4: Dot size ±0.4 µm, overall pitch accuracy ±2 µm

MATERIAL

Soda Lime Glass is widely used due to its high optical quality and cost-efficiency. It offers good UV transmission from 350 nm upwards, with 88% transmittance in the 375–750 nm range. The material is free from optical defects, has a flatness specification of 5 µm, and a thermal expansion coefficient of 93×10⁻⁷ K⁻¹.

White Diffuser Glass is a solid, semi-opaque version of soda lime glass with 30% light transmission. It provides uniform light diffusion without coatings or laminations and can be used in any orientation. The surfaces are polished to allow specular reflection while maintaining Lambertian transmission. Glass flatness is specified to 2 µm. Optional anti-glare coatings can be applied to reduce surface reflection for reflected-light applications.

TURNAROUND

Standard production turnaround is 5 days from receipt of order. Expedited services are available upon request for urgent requirements.

INSPECTION

All photomasks undergo a comprehensive inspection process. Key parameters such as Critical Dimension (CD) and feature uniformity are measured and recorded. High-magnification images (Nikon MM40 at 900×, OGP ZIP 300 at 400×) are stored with production data. For sectors requiring compliance documentation—such as medical or automotive—optional inspection certificates can be included with the order.

Standard: Full inspection performed; no documentation supplied.

Certificate of Conformance: Confirms compliance with internal inspection standards.

Certificate of Measurement: Up to 10 line/space dimensions (width and pitch) can be measured and documented. CAD or marked drawing may be required. Additional measurements available on request.

Please see the TECHNICAL sections, DOWNLOAD sections, and FAQ for further information. If you still require clarification, please email or click for LIVE SUPPORT.