Optical Resolution Charts, Ronchi Rulings and Grids

The optical resolution charts are used to test characteristics such as resolution, contrast, distortion and modulation transfer function (MTF) of lenses, cameras and optical systems. Ronchi rulings and grids are used to create interference patterns, to measure distortion and for MTF measurements.

EMS offers a range of charts on glass and in metal foil. Customers often require special charts for specific applications and these can be made to your exact requirements.

In addition to these products, we also supply a specialist NPL/HSE test slide for checking the resolving power of phase contrast microscopes – please see ref S84 in stage micrometers.

R70 USAF 1951 Test Chart

Groups 0 to 7

USAF resolution charts are recognized the world over as a universal standard for testing the vertical and horizontal resolution of imaging systems. Each element on the chart comprises three vertical bars and three horizontal bars, and the detail on these slides is as fine as 0.78 microns (644 line-pairs per mm). The resolution of the imaging system is normally specified as the Group and Element of the finest bars that can be clearly defined.

R71 USAF Test Chart

Group -2 to Group 7, Element 6

Large Positive Image
B270 glass, size 75mm x 75mm

R75P High Resolution Positive Image

USAF Test Chart Group 0 to Group 9, Element 3

High Resolution Positive Image
Soda Lime Glass 50mm x 50mm x 2mm
Sub Micron smallest feature size: bar width 0.00078mm [0.78µm]

R75N High Resolution Negative Image

USAF Test Chart Group 0 to Group 9, Element 3

Sub Micron smallest feature size – bar width 0.00078mm [0.78µm]
High Resolution Negative Image
Soda Lime Glass 50mm x 50mm x 2mm

PS75P High Resolution Positive Image

USAF Test Chart Groups 2 to 9, Element 3

Sub Micron smallest feature size - bar width 0.00078mm [0.78µm]
High Resolution Positive Image
Soda Lime glass mounted in Stainless Steel Microscope Slide
Engraved with unique serial number for traceability (75mm x 26mm)
Supplied in Polished Wooden Box

PS75N High Resolution Negative Image

USAF Test Chart Groups 2 to 9, Element 3

Sub Micron smallest feature size - bar width 0.00078mm
High Resolution Negative Image
Soda Lime glass mounted in Stainless Steel Microscope Slide
Engraved with unique serial number for traceability (75mm x 26mm)
Supplied in Polished Wooden Box

Star Test Targets

Specifications

Ordering

NBS 25 Resolution Charts

R60 NBS 25 Test Chart

3-30 Lines per mm Chrome surface image B270 Glass 50mm x 50mm

A series of gratings diminishing in size as they go towards the central target. Lines range from 3 lines per mm to 20 lines per mm. Supplied as a positive high contrast chrome image on glass substrate 50mm x 50mm.

Also available in low contrast and negative form.

NBS 5 Bar Test (BS4657)

1-18 lines per mm Chrome Surface Image B270 Glass 75mm x 75mm

This consists of elements of 5 bars ranging from 1 line per mm to 18 lines per mm, with adjacent numbers indicating the number of lines per mm. Produced as a vacuum deposited chrome image on 75mm x 75mm glass.

R72 Sayce Logarithmic Test Chart

This chart is a photographic image featuring 90 lines and spaces of gradually decreasing width in logarithmic series. The charts have a base length of 100mm and are supplied on 0.175mm thick ester-based film. Typically in use, the image is examined to determine the finest detail that can be distinguished. The finest resolved line is then counted to define the resolution of the device. Includes 6 charts, resolution table and for use.

Grids

Consists of elements of 5 bars ranging from 1 line per mm to 18 lines per mm, with adjacent numbers indicating the number of lines per mm. Produced as a vacuum deposited chrome image on 75mm x 75mm glass.

Gratings-Ronchi Rulings

Metallic grating pattern on glass squares with opaque lines approximately 50% of the pitch. Stock items are on 50mm x 50mm squares of glass 1.5mm thick. The grating covers the entire plate with the exception of R25, R26 and R27, where the grating occupies a 30mm wide central strip. The glass is B270 with refractive index of 1.52.

Uses

• Paired as light gates
• Demonstrate interference patterns
• Produce optical gradients

Mutually perpendicular pairs produce a screen of square apertures.

Vacuum deposited chrome gratings on glass substrate. Typically used for testing of resolution, field distortion and parfocal stability, but may be paired to provide interference patterns (fringe patterns) and as light gates.

Counting Chambers