Objectives

A large choice of objectives

Digital Holographic Microscopes (DHM®) have a unique optical configuration compared to classical interferometers: the reference path is not build-in the microscope objective but is integrated in the DHM® head.  This enables DHM® to be used with a large range of objective types as conventional optical microscopes rather than to be limited by expensive interferometric Michelson or Mirau objectives. Therefore DHM® takes advantage of the multiple measurement possibilities offered with classical objectives.

  • Magnification from 1.25× up to 100× with numerical apertures up to 0.90 in air and 1.4 in oil immersion
  • Long working distance objectives to measure sample areas difficult to approach or in presence of interaction probes. Such objectives are available with low as well as with high magnification and high NA
  • Water immersion objectives to measure immersed samples
  • Objectives with correction for various glass window and cover-slip thicknesses
  • Objectives optimized for simultaneous fluorescence measurements

Lyncée Tec provides sets of objectives adapted to the DHM® turret. All the objectives have the same parfocal length ensuring a constant focus without moving the sample when changing the objective. The objectives delivered with the DHM® are tested and selected for best performances. They are factory calibrated and configured for immediate use.

Moreover, with DHM® the same optical configuration is kept whatever the sample’s reflectivity is. A single objective is needed when working with different sample reflectivity and no manipulation is required when the reflectivity changes.

Objectives for DHM
Magnification vs. Field of view

The large collection of objectives available allows to always measure with optimal optical quality.

Selection criteria are identical to conventional optical microscopy. As presented on the opposite chart, the objectives are specified by their magnification, field of view and lateral resolution.

As with any optical method, for reflection configured DHM®, the reflected signal acquired is determined by the surface structure and material reflective property: steep slopes on the sample surface and diffusive materials will limit the quality of the reflected signal that can be acquired by the objective. The acceptance slope angles are not limited by the objective, but by the total reflection of the incident beam on the interface.

For transmission configured DHM®, the specimen is in air if no immersion medium is indicated. The maximum slope depends on the specimen’s refractive index. Use of immersion liquid with calibrated refractive index enables to increase maximum slop measured and  measure high aspect-ratio elements.

Lyncée Tec has the competencies to advise the best adapted configuration and objectives to your applications and samples.

A motorized linear objective changer

The linear objective changer enables automated selection of magnification on DHM-R series. It is not available for DHM-T series

For ensuring speed and accuracy shaft linear motors are used. It enable to change between nearby lenses in 0.2 seconds, and across five lenses in only 0.4 seconds. The linear objective changer complies with clean room class 10 SEMI.

A motorized linear objective changer

Specifications

Specifications for standard available objectives are as follow. Additional types may be available on request.

Objectives specifications are given regarding features described under following tables.

Standard dry type

Magnification Numerical aperture Working distance [mm] Glass thickness [mm] Immersion Field of View [um] (square) Lateral resolution [um] Depth of Field [um] Maximum Slope [°] DHM®-R  Maximum Slope [°] DHM®-T
1.25x 0.04 3.70 5280 8.50 555 1.1 4.5
2.5x 0.07 11.2 2640 4.90 175 2 7.9
5x 0.12 14.0 1320 2.85 58 3.4 13.3
10x 0.30 11.0 660 1.15 9.75 8.7 28.7
20x 0.40 1.15 330 0.85 5.0 11.7 34.4
40x 0.75 0.37 165 0.45 1.43 24.3 41.8
50x 0.80 0.50 132 0.43 1.23 26.6 41.8
100x 0.90 1.0 66 0.38 0.91 32.1 41.8

Long Working Distance type

Long working distance objectives are available for Reflection DHM® and on request only for Transmission DHM®.

Magnification Numerical aperture Working distance [mm] Glass thickness  [mm] Immersion Field of View [um] (square) Lateral resolution [um] Depth of Field [um] Maximum Slope [°] DHM®-R  Maximum Slope [°] DHM®-T
20x 0.40 10.80 330 0.85 5.0 11.7 34.4
50x 0.50 8.20 132 0.70 3.00 15.0 38.2
100x 0.75 4.70 66 0.45 1.30 24.3 41.8

Long Working Distance and glass thickness correction type

Magnification Numerical aperture Working distance [mm] Glass thickness [mm] Immersion Field of View [um] (square) Lateral resolution [um] Depth of Field [um] Maximum Slope [°] DHM®-R  Maximum Slope [°] DHM®-T
20x 0.40 6.90 0-2.0 330 0.83 5.0 11.7 34.4
40x 0.60 3.3-1.9 0-2.0 165 0.56 2.1 18.4 40.6
63x 0.70 2.60 0.1-1.3 110 0.48 1.5 22.2 41.7

Immersion water and oil type

Water immersion objectives are available for Reflection DHM® only.
Oil type objectives are available for both Reflection DHM® and Transmission DHM®.

Magnification Numerical aperture Working distance [mm] Glass thickness [mm] Immersion Field of View [um] (square) Lateral resolution [um] Depth of Field [um] Maximum Slope [°] DHM®-R  Maximum Slope [°] DHM®-T
10x 0.30 3.60 Water 660 0.86 13.0 6.5 55.7
20x 0.50 3.50 Water 330 0.51 4.5 11.0 61.8
40x 0.80 3.30 Water 165 0.30 1.6 18.5 62.4
63x 0.90 2.20 Water 110 0.30 1.3  21.3 62.4
63x 1.30 0.16 0.17 Oil 110  0.18 0.8 27.8  89.9
100x 1.30 0.13 0.17 Oil 66 0.17 0.7 29.5 89.9

Cover-glass correction type

Magnification Numerical aperture Working distance [mm] Glass thickness [mm] Immersion Field of View [um] (square) Lateral resolution [um] Depth of Field [um] Maximum Slope [°] DHM®-R  Maximum Slope [°] DHM®-T
20x 0.50 1.15 0.17 330 0.67 3.31 15.0 38.2
40x 0.75 0.40 0.17 165 0.44 1.40 24.3 41.8

 

  • Magnification
    • Magnifying power of the objective
  • Numerical Aperture
    • Sine of the half-angle of the objective acceptance cone, NA
  • Working Distance
    • Distance from the end of the objective to the test surface when focused or to the cover glass bottom for cover glass corrected objectives
  • Cover Glass
    • Thickness of the cover glass for witch the objective compensates the induced aberrations
  • Immersion
    • Objectives specially designed for indicated liquid filling the air gap between object and objective
  • Field of View
    • Square imaged area of the test part
  • Lateral Resolution
    • Optical resolution of the imaging system given by the Sparrow criteria
  • Depth of Field
    • Thickness of the specimen that is acceptably sharp at a given focus level
  • Maximum Slope
    • Maximum slope angle of the specimen for which information can be collected. Spec is given specifically for DHM®-R and DHM®-T types