The structure of the objective lens is complex and precise, usually composed of a combination of lenses, with each lens spaced at a certain distance to reduce the difference. Each group of lenses is made by bonding one or several lenses with different materials and parameters. There are many specific requirements for the objective lens, such as axial alignment and alignment. The modern microscope objective has reached a high level of perfection, with its numerical aperture approaching its limit, and the difference between the resolution at the center of the field of view and the theoretical value is negligible. However, the possibility of further increasing the field of view of the microscope objective and improving the imaging quality of the field edge still exists, and this research work is still ongoing to this day.

Objective lens microscopefunction

Objective lensand eyepiecelensmagnification

There are typically several objective lenses on a microscope, each with a different magnification power. The user can switch between the lenses to observe different parts of the specimen at different levels of magnification.

Aligning focus is not only used in microscopy, but also when observing images clearly with a certain magnification objective, and when switching to another magnification objective, the imaging should be basically clear, and the center deviation of the image should also be within a certain range, that is, the degree of axis alignment. The quality of confocal performance and the degree of alignment are important indicators of microscope quality, which are related to the quality of the objective lens itself and the accuracy of the objective lens converter.

Objective lensmagnification

The objective lens is the most important optical component of a microscope, which uses light to create the first image of the object being tested. Therefore, it directly affects and affects the quality of the image and various optical technical parameters, and is the primary standard for measuring the quality of a microscope.

Microscopic objective is an aberration cancelling system. This means that for a pair of conjugate points on the axis, when the aberration is eliminated and the sine condition is achieved, each objective only has two such aberration cancellations. Therefore, any change in the calculated position of the object and image results in an increase in aberration. On the rotator installed at the lower end of the lens barrel, there are generally 3-4 objective lenses, among which the shortest one engraved with the "10 ×" symbol is a low magnification lens, the longer one engraved with the "40 ×" symbol is a high magnification lens, and the longest one engraved with the "100 ×" symbol is an oil lens. In addition, a circle of different colors is often added to the high magnification lens and the oil lens to show the difference.

The objective lens is called such because it is the lens closest to the object being observed. The magnification power of a microscope is determined by the magnification of the objective lens and the magnification of the eyepiece or tube lens.

Objective lens

What are the 3objectivelenses on amicroscope

Part No.NAWD (mm)FL (mm)Resolution (µm)± DOF (μm)Field NumberFOV (mm)Weight (g)ThreadPlanFluor-EPI-5X0.1520401.8012.00255.0057W4/5″ x 1/36″PlanFluor-EPI-10X0.3011200.903.10252.5065W4/5″ x 1/36″PlanFluor-EPI-20X0.453100.601.40251.2577W4/5″ x 1/36″PlanFluor-EPI-50X0.80140.340.43250.5089W4/5″ x 1/36″PlanFluor-EPI-100X0.90120.310.34250.2590W4/5″ x 1/36″PlanFluor-EPI-BD-5X0.1520401.8012.00255.0078M26 x 0.706PlanFluor-EPI-BD-10X0.3011200.903.10252.5095M26 x 0.706PlanFluor-EPI-BD-20X0.453100.601.40251.25111M26 x 0.706PlanFluor-EPI-BD-50X0.80140.340.43250.50123M26 x 0.706PlanFluor-EPI-BD-100X0.90120.310.34250.25122M26 x 0.706L-PlanFluor-EPI-20X0.4012100.701.70251.2565W4/5″ x 1/36″L-PlanFluor-EPI-50X0.5010.440.551.10250.5068W4/5″ x 1/36″L-PlanFluor-EPI-100X0.803.120.340.43250.2588W4/5″ x 1/36″

The aberration related to a wide beam of light is spherical aberration, coma aberration, and positional chromatic aberration; The aberrations related to the field of view are astigmatism, field curvature, distortion, and magnification aberration.

Apochromatic microscope objective lenses are infinite optical systems available in several magnifications working in the spectral region from 355nm to 1064nm. It is ideal for co-axial vision for real-time monitoring such as laser processing, micro-imaging, DIC imaging, and fluorescence inspection in bio-imaging. It is also used to laser repair the touch panel and the solar cell.

The Tube Lens is designed to use together with the objective lens for imaging applications. It acts as a secondary lens by allowing light to pass through the body of the tube as parallel rays from the objective lens. These parallel rays are focused by the tube lens to form an intermediate image with minimal aberration.

3 types ofobjectivelenses

Part No.NAWD (mm)FL (mm)Resolution (µm)± DOF (μm)Wavelength (nm)FOV φ24 mmFOV 1″ CCD (mm)Weight (g)M-PlanAPO-1X0.02513.0200.0011.00440.00400-70024.009.60 x 12.80240M-PlanAPO-2X0.05534.0100.005.0091.00400-70012.004.80 x 6.40206M-PlanAPO-3.5X0.10041.057.142.8028.00400-7006.902.70 x 3.60218M-PlanAPO-5X0.14035.040.002.0014.00400-7004.801.92 x 2.56212M-PlanAPO-7.5X0.21034.026.671.306.20400-7003.601.28 x 1.70247M-PlanAPO-10X0.28034.020.001.003.50400-7002.400.96 x 1.28217M-PlanAPO-15X0.35022.013.330.802.20400-7001.800.64 x 0.85240M-PlanAPO-20X0.42020.010.000.701.60400-7001.200.48 x 0.64271M-PlanAPO-50X0.55013.04.000.500.90400-7000.480.19 x 0.26298M-PlanAPO-HR-5X0.21025.040.001.306.20400-7004.801.92 x 2.56251M-PlanAPO-HR-10X0.42015.020.000.701.60400-7002.400.96 x 1.28382M-PlanAPO-HR-20X0.6009.510.000.500.76400-7001.200.48 x 0.64563M-PlanAPO-HR-100X0.9001.42.000.300.34400-7000.240.10 x 0.13362M-PlanAPO-SL-20X0.29030.010.000.903.30400-7001.200.48 x 0.64236M-PlanAPO-SL-50X0.42020.04.000.701.60400-7000.480.19 x 0.26286M-PlanAPO-SL-100X0.55013.02.000.500.90400-7000.240.10 x 0.13302M-PlanAPO-NIR-20X0.42020.010.000.651.56532/1030-10641.200.48 x 0.64377M-PlanAPO-NIR-50X0.55013.04.000.500.91532/1030-10640.480.19 x 0.26394M-PlanAPO-HRNIR-20X0.6009.510.000.460.76532/1030-10641.200.48 x 0.64563i-PlanAPO-HRNIR-50X0.67010.04.000.410.61532/1030-10640.480.19 x 0.26470M-PlanAPO-HRNIR-50X0.7504.04.000.370.49532/1030-10640.480.19 x 0.26582LCD-PlanAPO-NIR-20X(t0)0.40020.010.000.701.70532/1030-10641.200.48 x 0.64260LCD-PlanAPO-NIR-20X(t0.7)0.40020.010.000.701.70532/1030-10641.200.48 x 0.64259LCD-PlanAPO-NIR-20X(t1.1)0.40020.010.000.701.70532/1030-10641.200.48 x 0.64258LCD-PlanAPO-NIR-50X(t0)0.45015.04.000.601.40532/1030-10640.480.19 x 0.26300LCD-PlanAPO-NIR50X(t0.7)0.45015.04.000.601.40532/1030-10640.480.19 x 0.26299LCD-PlanAPO-NIR50X(t1.1)0.45015.04.000.601.40532/1030-10640.480.19 x 0.26298M-PlanAPO-NUV-20X0.42017.010.000.651.56355, 532 & 365, 4051.200.48 x 0.64268M-PlanAPO-HRNUV-50X0.65010.04.000.420.65355, 532 & 365, 4050.480.19 x 0.26405LCD-PlanAPO-NUV-20X(t0)0.40020.010.000.701.70355, 5321.200.48 x 0.64262LCD-PlanAPO-NUV-20X(t0.7)0.40020.010.000.701.70355, 5321.200.48 x 0.64261LCD-PlanAPO-NUV-20X(t1.1)0.40020.010.000.701.70355, 5321.200.48 x 0.64260LCD-PlanAPO-NUV-50X(t0)0.45015.04.000.601.40355, 5320.480.19 x 0.26295LCD-PlanAPO-NUV-50X(t0.7)0.45015.04.000.601.40355, 5320.480.19 x 0.26294LCD-PlanAPO-NUV-50X(t1.1)0.45015.04.000.601.40355, 5320.480.19 x 0.26293

Microscopic objective and eyepiece differ in their involvement in imaging. Objective is the most complex and important part of a microscope, operating in a wide beam of light (with a large aperture), but these beams have a smaller inclination angle to the optical axis (with a smaller field of view); The eyepiece works in a narrow beam of light, but its inclination angle is large (with a large field of view). When calculating the objective and eyepiece, there is a significant difference in eliminating aberration.

An objective lens of a microscope is responsible for gathering and focusing light from the specimen being observed to produce an image. It is typically located near the bottom of the microscope’s body and consists of a series of lenses that work together to magnify the image of the specimen.