Phase contrast microscope

Introduction

A phase contrast microscope is a light microscope that uses the phase contrast technique to enhance the contrast of the transparent and the unstained specimens, and it is used in the biology, the cell biology, the microbiology, and the clinical laboratories for the observation of the living cells and the other transparent specimens. The phase contrast microscope consists of a light microscope with the special optical components, including the annular diaphragm in the condenser, which forms a hollow cone of the light, and the phase plate in the objective, which shifts the phase of the light, and the technique converts the phase differences of the light passing through the specimen into the intensity differences, enhancing the contrast of the transparent structures; the phase contrast microscope is used for the observation of the living cells in the culture, for the observation of the unstained microorganisms, for the observation of the cell structures, such as the nuclei and the organelles, for the observation of the transparent specimens, for the monitoring of the cell culture, and for many other applications, and it is available as the microscope with the phase contrast objectives and the condensers, with the features such as the various magnifications and the imaging; the phase contrast microscope is an essential instrument for the observation of the living and the transparent specimens. Phase contrast microscopes are used in the cell biology and the microbiology laboratories, in the clinical laboratories, in the research institutions, and for many other applications. With their phase contrast, phase contrast microscopes are essential for the observation of the transparent specimens.

Phase Contrast Microscope LPMC-T2010

Phase Contrast Microscope delivers 40x to 1000x magnification for enhanced imaging clarity. It features an infinity optical system for sharp, aberration-free observations. A 30° incline...

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Standards

ISO 9345:2019-Microscopes-Interfacing dimensions for imaging components

Complies with the above standards, but is not limited to them.

Features

1. Phase contrast microscope for visualizing transparent, unstained specimens by converting phase shifts into contrast.

2. Compound microscope with phase contrast condenser and phase objectives for live cells and unstained samples.

3. Suitable for cell culture, microbiology, hematology, biological research and clinical laboratory applications.

4. Includes microscope body, phase condenser, phase objectives (10x, 20x, 40x, 100x oil), eyepieces, light source and manual.

5. Supports observation of living cells, bacteria, tissue cultures, blood cells and transparent specimens without staining.

FAQ

Q1: What testing scenarios is this microscope mainly applied to?

A: The phase contrast microscope is used in cell culture, microbiology, hematology, biological research, and clinical laboratories to visualize transparent, unstained specimens (living cells, bacteria, tissue cultures) by converting phase shifts of light passing through the specimen into brightness differences (contrast), allowing observation without staining or fixation (which kills cells). It supports cell culture (routine monitoring of adherent and suspension cell cultures (mammalian cells, stem cells, cell lines) - check confluence, morphology, health, contamination (yeast, bacteria, mycoplasma), growth rate; essential daily tool in cell culture labs; phase contrast makes unstained live cells visible (brightfield shows very little contrast for transparent cells)), microbiology (observation of live bacteria (motility, morphology - rods, cocci, spirilla), yeast, fungi, protozoa; wet mount preparations; antimicrobial susceptibility testing (motility inhibition), urine sediment analysis (crystals, casts, cells - clinical urinalysis), hematology (blood cell morphology (though stained smears are standard for differential; phase contrast can examine unstained blood, sickle cells, platelet clumping), parasite examination (wet mounts for malaria (though Giemsa stain standard), intestinal parasites in stool wet mounts - eggs, larvae, protozoa (Giardia, Entamoeba)), biological research (live cell imaging (cell division, migration, apoptosis, phagocytosis), sperm analysis (motility, morphology - andrology/fertility), tissue section observation (unstained, before staining), developmental biology (embryos, small organisms), and clinical diagnostics (urinalysis (sediment), CSF (cerebrospinal fluid) cell count, body fluid analysis, semen analysis). Phase contrast principle: Light passes through annular ring in condenser -> phase plate in objective shifts direct light by 1/4 wavelength and attenuates it -> light passing through specimen (different refractive index/thickness) is phase-shifted -> interference between direct and diffracted light creates contrast (bright or dark depending on positive/negative phase contrast). Invented by Frits Zernike (1932, Nobel 1953). Allows observation of live, unstained cells in their natural state - critical for cell culture where staining would kill cells.

Q2: What standards does the microscope comply with?

A: The phase contrast microscope follows relevant ISO, IEC, ASTM and GB/T standards including ISO 11171 (particle size analysis - microscopy, related), ISO 16212 (cosmetics - microbiology - yeast/mold enumeration - microscopy), IEC 61010 (laboratory electrical equipment safety), IEC 60825 (laser safety - if laser autofocus), ASTM standards for microscopy, CLSI (Clinical and Laboratory Standards Institute) guidelines for urinalysis, body fluid analysis, semen analysis (WHO laboratory manual for semen analysis), and GB/T standards for microscopes. The hardware complies with applicable optical standards (resolution, magnification accuracy, phase contrast alignment), EMC (IEC 61326), and safety (IEC 61010). For clinical use (urinalysis, semen, body fluids), follow CLSI, WHO, and applicable accreditation (ISO 15189, CAP, Joint Commission). For cell culture, follow GLP/good cell culture practice and facility SOPs. For research, follow journal/grant requirements for imaging. For regulated labs, maintain equipment qualification (IQ/OQ), calibration (focus, magnification, phase alignment), and maintenance records. Phase contrast alignment (Kohler illumination, phase ring centering) is critical for image quality - verify periodically.

Q3: What is the warranty period for the whole microscope and key components?

A: The whole phase contrast microscope is covered by a 12-24 month warranty (optical instruments often 2-5 years for body, 1 year for electronics/lamps). The microscope body, objectives, eyepieces, condenser, and stage are covered, while light source/lamps (halogen or LED - halogen burns out (100-1000 hours; LED lasts 10000+ hours), replacement available), immersion oil (consumable - for 100x oil objective), filters (wear), and fuses are consumables/accessories. Damage from improper use, objective/eyepiece scratches (dust, improper cleaning - use lens paper, proper solvent), oil immersion objective contamination (oil on non-oil objectives, dried oil - clean promptly), dropping/impact (optics are sensitive), liquid spills (corrode stage/optics), dust contamination (keep covered, use dust cover), or unauthorized repair is excluded. Extended warranty and service contracts (preventive maintenance, lamp replacement, optics cleaning) may be available. Optics/body last 10-20+ years with proper care; halogen lamp 100-1000 hours (replace periodically); LED 10000+ hours (years).

Q4: Is this device difficult to operate? Is professional training required?

A: Operation is straightforward for basic observation, but proper Kohler illumination and phase contrast alignment are important for image quality. No professional training required for routine cell culture use, but training on phase alignment and Kohler is recommended. We provide operation manuals. Proper setup (place on stable, vibration-free bench (microscopes are sensitive to vibration - use heavy bench, avoid near centrifuges/equipment), connect power, turn on light source (allow halogen to warm/stabilize; LED instant), install eyepieces, rotate to lowest power objective (10x) for initial focusing), Kohler illumination setup (CRITICAL for even illumination and phase contrast: focus on specimen, close field diaphragm, adjust condenser height/focus until diaphragm edges sharp, center diaphragm with condenser centering screws, open field diaphragm to just beyond field of view, adjust aperture diaphragm for contrast/resolution (for phase contrast, aperture diaphragm should be set to match phase ring - typically open to phase ring position)), phase contrast alignment (each phase objective has a phase ring; condenser has matching annulus; for each objective, center the phase annulus (use phase telescope or Bertrand lens to align annulus with phase ring - misaligned = poor contrast, halos); some microscopes have labeled positions (Ph1, Ph2, Ph3) matching objectives), sample preparation (wet mount (drop of sample on slide, coverslip - for live cells, bacteria, urine sediment; avoid bubbles), cell culture flask/dish (observe directly through flask bottom (inverted microscope) or remove cells to slide; for upright phase contrast, use slide/coverslip), blood/semen (wet mount or counting chamber (hemocytometer)), operation (start at 10x, focus with coarse then fine adjustment, center specimen, increase magnification (20x, 40x, 100x oil), for 100x oil: add small drop of immersion oil on coverslip (or condenser for inverted), rotate oil objective into oil (do not get oil on other objectives), focus carefully (fine focus only - oil objective has short working distance), observe (phase contrast shows cells with bright/dark halos, internal structures visible), adjust light intensity (too bright = glare, cell damage for live cells; too dim = poor contrast), for live cell imaging: minimize light exposure (phototoxicity), post-operation (turn off light (extend lamp life), lower stage, rotate to 10x or no objective, clean oil immersion objective (lens paper + lens cleaner - remove all oil; dried oil damages objective), clean stage (spills, media), cover with dust cover, maintenance (daily: wipe stage, clean oil objective after use, cover; weekly: clean eyepieces/objectives (lens paper, lens cleaner - do not use Kimwipes/paper towels (scratches); do not use alcohol on coated optics unless approved), check lamp, clean condenser; monthly: verify Kohler/phase alignment, inspect optics for fungus/dust (store in dry environment, use desiccant if humid), semi-annually/annually: professional cleaning/alignment (optics, stage, focus mechanism), lamp replacement (halogen), troubleshooting (poor contrast/blurry (Kohler not set, phase ring misaligned, objective not matched to condenser annulus (use Ph1/Ph2/Ph3 correctly), oil on non-oil objective, dirty lens, wrong aperture diaphragm - set Kohler, align phase, clean optics, use correct objective/annulus), image has halos (normal for phase contrast (positive phase = bright halos around cells; negative phase = dark); excessive halos = misalignment or wrong phase plate - align, use appropriate phase), no image/too dark (light off, field diaphragm closed, aperture diaphragm closed, wrong filter, lamp burned out - turn on, open diaphragms, replace lamp), cannot focus (specimen not on stage, coverslip wrong thickness (use #1.5 coverslips for high NA objectives), objective not clicked into place, working distance issue (oil, thick sample), stage too high/low - check specimen, coverslip, objective), oil on non-oil objective (clean immediately with lens cleaner - oil degrades non-oil objectives), image moves/drifts (stage not locked, sample not flat, thermal drift - lock stage, use flat slide, allow warm-up), and safety (OPTICAL (do not look directly at bright light source (halogen/LED can be intense - use diffuser, adjust intensity; for UV/fluorescence (if equipped) - eye protection), GLASS (slides/coverslips are glass - handle carefully, broken glass = sharps; dispose properly), BIOLOGICAL (samples may contain pathogens (clinical specimens, cell cultures - wear gloves, lab coat, eye protection; decontaminate spills; dispose biohazard waste; for blood/body fluids - follow bloodborne pathogen protocols), CHEMICAL (immersion oil (low toxicity but avoid eye/skin contact; cleaning solvents (alcohol, xylene) - flammable, use fume hood, PPE), ELECTRICAL (proper grounding, do not use with wet hands, do not spill liquid on microscope), do not touch lenses with fingers (oil/dust damages coatings; use lens paper), do not use paper towels/Kimwipes on optics (scratches), for live cell work: maintain sterile technique (do not open flasks unnecessarily, work in biosafety cabinet), minimize phototoxicity (short exposure, lower intensity), for clinical samples: follow biosafety levels (BSL-2 for blood/body fluids), do not leave microscope on unattended (lamp heat, fire risk)) are important for safe and effective phase contrast microscopy.

Q5: What is the typical lead-time for order delivery?

A: Standard models require 7-30 working days. In-stock units can ship within 3-7 working days. Custom configurations or large built-to-order systems may require additional time, and we confirm the exact schedule before order confirmation.

Q6: Is regular calibration required? What is the recommended calibration cycle?

A: Calibration/performance verification recommended every 6-12 months (or per quality system): magnification calibration (with stage micrometer - verify objective magnification, eyepiece reticle calibration for measurement), resolution check (with resolution target), Kohler/phase alignment verification, and light intensity/color temperature. Routine: verify Kohler illumination and phase ring alignment whenever changing objectives or if image quality degrades (misalignment is common - check weekly/monthly). For clinical labs (ISO 15189, CAP, Joint Commission), follow applicable schedules and maintain records (calibration certificates, stage micrometer traceability, alignment logs, lamp hours). For cell culture, phase alignment should be checked periodically (poor alignment = poor cell visibility, can lead to missed contamination or wrong confluence estimates). For quantitative work (cell counting, size measurement), calibrate eyepiece reticle with stage micrometer for each objective (reticle units = micrometers). Lamp replacement (halogen) does not require recalibration but verify intensity. For research imaging, follow journal/funder requirements for image integrity (no manipulation, maintain raw data).

Q7: Are supporting consumables universal?

A: Immersion oil (Type A/B, for 100x oil objective - universal from microscopy supply (Cargille, Olympus, Nikon; use low-fluorescence if fluorescence), slides and coverslips (#1.5 thickness for high NA - universal from Fisher, VWR, Thermo), light source/lamps (halogen bulb specific to model; LED long-life), lens paper/lens cleaner (universal), dust cover (specific or universal), and counting chambers (hemocytometer - universal) are available from lab supply companies, though lamps and some filters are microscope-specific (use OEM or certified compatible). Objectives are brand-specific (do not mix brands on same microscope without checking compatibility - parfocal distance, thread). Long-term consumable cost includes immersion oil (regular), slides/coverslips (regular), and lamp replacement (periodic).

Q8: Can I customize parameters or supporting accessories?

A: Customization includes type (upright (standard, for slides/specimens) or inverted (for cell culture flasks/dishes, live cell imaging - objectives below stage)), objectives (10x Ph1, 20x Ph1/Ph2, 40x Ph2, 100x oil Ph3 - phase contrast matched; plan achromat, plan fluorite, plan apochromat (higher quality); NA 0.25-1.4), head (monocular, binocular, trinocular (for camera)), eyepieces (10x wide field, with/without reticle for measurement), condenser (phase contrast with annuli (Ph1, Ph2, Ph3), brightfield/darkfield, Abbe), light source (halogen (warm, replaceable) or LED (long-life, cool, adjustable intensity, daylight balance)), stage (fixed, mechanical (X-Y movement), rotating), focus (coarse/fine, tension adjustment, rack stop), digital imaging (camera (CMOS/CCD, 5MP-20MP+), image analysis software (cell counting, measurement, documentation), USB/WiFi output), fluorescence (add fluorescence illuminator/filters for combined phase + fluorescence - common for cell biology), accessories (extra objectives, eyepieces, immersion oil, slides/coverslips, stage micrometer (calibration), counting chamber (hemocytometer), dust cover, spare lamp, lens cleaning kit, calibration certificate, certifications (CE, ISO 9001, IEC 61010), language and accessories. Additional objectives, camera, and accessories can be ordered separately.

Q9: Does the purchase include on-site installation and commissioning service?

A: Standard delivery includes phase contrast microscope, objectives (selected), eyepieces, phase condenser, light source, power cord, and instruction manual. On-site installation is not required for standard microscopes (unbox, assemble, set Kohler/phase alignment, use). On-site training is not included for standard orders but can be arranged at additional cost (for clinical/cell culture teams on Kohler/phase alignment, sample prep, imaging, and maintenance). Remote guidance provided. For high-end research systems (fluorescence, digital imaging, motorized): on-site installation/commissioning may be required/recommended. Always align Kohler and phase rings before first use.

Q10: What types of samples are compatible with this equipment?

A: The phase contrast microscope visualizes various transparent/unstained samples including living cells (mammalian cell cultures (adherent/suspension), stem cells, primary cells, bacteria (live, motility), yeast, fungi, protozoa), body fluids (urine sediment (casts, crystals, cells), CSF (cells, bacteria), semen (sperm motility/morphology), blood (unstained, sickle cells, platelets)), tissue/cell preparations (wet mounts, cell smears, tissue homogenates, thin tissue sections (unstained)), environmental samples (water (algae, protozoa, bacteria), soil extracts), and small organisms (nematodes, embryos, microorganisms). NOT compatible with: Opaque/thick samples (phase contrast is for transmitted light - samples must be thin/transparent; thick samples need sectioning or stereomicroscope/dissecting scope), samples requiring high resolution beyond light microscope (~0.2 micrometer limit - use electron microscope for viruses, subcellular structures), stained samples (phase contrast works but brightfield may be better for stained samples; phase can add halos), samples in plastic vessels with thick bottoms (for inverted microscopes, use glass-bottom dishes for high-NA objectives; standard plastic flasks work for low/medium power), and samples requiring fluorescence only (phase contrast is transmitted light; add fluorescence module if needed). For 100x oil objective: requires coverslip (#1.5, 0.17 mm) and immersion oil; cannot use with uncovered samples or thick plastic. For quantitative measurement: use calibrated eyepiece reticle and stage micrometer. IMPORTANT: Phase contrast microscope fundamentals: (1) What it does: Converts phase shifts of light passing through transparent specimens into brightness (amplitude) differences, making unstained/live cells visible. Without phase contrast, transparent cells in brightfield show almost no contrast (they absorb very little light). Phase contrast uses interference to create contrast from differences in refractive index and thickness. (2) How it works: - Annular diaphragm in condenser: Creates a hollow cone of light. - Phase plate in objective: Has a phase ring that (a) shifts direct (undeviated) light by 1/4 wavelength and (b) attenuates it (reduces brightness). - Light passing through specimen: Specimen (different refractive index/thickness than medium) causes some light to diffract/phase-shift by ~1/4 wavelength. - Interference: Direct light (shifted by phase plate) and diffracted light (shifted by specimen) interfere. For positive phase contrast: destructively interfere where specimen is thicker/higher RI = dark specimen on bright background (most common). Negative phase: bright specimen on dark background. - Result: Live, unstained cells visible with internal detail (nucleus, organelles, membranes). (3) Key components: - Phase contrast condenser: Has annuli (rings) for each objective (Ph1 for 10x, Ph2 for 20x/40x, Ph3 for 100x). Must match objective. - Phase objectives: Each has phase plate (ring) in back focal plane. Labeled Ph1, Ph2, Ph3. - Phase telescope/Bertrand lens: Used to align annulus with phase ring (centering). - Kohler illumination: Required for even illumination and proper phase contrast. (4) Positive vs negative phase: - Positive phase (most common): Specimen appears darker than background (dark cells on bright field). Good for general cell culture. - Negative phase: Specimen appears brighter than background (bright cells on dark field). Used for some applications (e.g., chromosomes). (5) Advantages: - View live, unstained cells (no fixation/staining = no killing, no artifacts). - Observe dynamic processes (cell division, movement, apoptosis). - Simple, no special sample prep (wet mount or culture vessel). - Inexpensive compared to fluorescence. (6) Limitations: - Halos around specimens (optical artifact - bright/dark ring around cells; more pronounced at edges). - Not good for thick samples (phase shifts too complex, multiple scattering). - Lower resolution than some methods (annulus reduces effective NA). - Does not show specific molecules (unlike fluorescence/IHC). - Requires matched phase condenser + objectives. - Colorless (grayscale image). (7) Phase contrast vs other methods: - Brightfield: For stained samples; poor for unstained/transparent. - Phase contrast: For live/unstained cells; converts phase to contrast. - Differential Interference Contrast (DIC/Nomarski): Similar purpose, higher resolution, no halos, but more expensive, requires polarized light, not good for plastic/birefringent samples. - Darkfield: For small/transparent specimens (bacteria), bright on dark background. - Fluorescence: For specific molecules/proteins with fluorophores; more specific, but requires staining/labeling, can be toxic. - For routine cell culture: Phase contrast is standard (inverted phase microscope). (8) Kohler illumination (critical for phase contrast): 1. Focus specimen. 2. Close field diaphragm. 3. Raise/lower condenser until diaphragm edges sharp. 4. Center diaphragm with condenser screws. 5. Open field diaphragm to just beyond field. 6. Adjust aperture diaphragm (for phase, match to phase ring). This ensures even illumination and proper phase contrast. (9) Phase alignment: - Use phase telescope (pull out eyepiece, insert phase telescope) or Bertrand lens. - See two rings: bright annulus (from condenser) and dark phase ring (in objective). - Center annulus with condenser centering screws until rings overlap. - Do this for EACH phase objective (Ph1, Ph2, Ph3). - Misaligned = poor contrast, uneven illumination, halos. (10) Common errors: - Not setting Kohler (uneven illumination, poor contrast). - Phase ring not centered (halos, poor contrast). - Wrong phase annulus for objective (Ph1 with 40x = poor contrast). - Oil on non-oil objectives (damages lens). - Wrong coverslip thickness (#1.5 needed for high NA; wrong thickness = spherical aberration, blurry). - Not cleaning oil objective after use (dried oil damages lens). - Using paper towels on optics (scratches). - Too much light (glare, phototoxicity for live cells). - Forgetting immersion oil with 100x objective (no image, poor resolution). - Looking at live cells too long (phototoxicity, temperature change).