# Part name:
Polarising phase annulus 10x for PZO KS microscope condenser | K3PhZ and K3Ph1 compatible, stereoscopic contrast

# Original page URL:
https://www.microscopeparts.eu/part/pzo-mb-30s-polarising-phase-annulus-10x-for-pzo-ks-microscope-condenser-k3phz-and-k3ph1-compatible-99860

# Part manufacturer:
PZO

# Full manufacturer name:
Polskie Zaklady Optyczne

# Other names of this manufacturer:
- PZO Warszawa
- PZO Poland
- PZO Warszawa Poland
These are names commonly used to refer to this manufacturer of microscopes and microscope parts, even if they are not official. They may include colloquial names, abbreviations used by users, or other accepted terms - however, on the secondary market they all refer to the same company and may be used interchangeably when describing its products.

# Belongs to category:
Condensers

# Description and specifications:
Polarising phase annulus for a 10x objective, for the PZO KS stereoscopic phase contrast condenser, compatible with PZO K3Ph, K3PhZ and other condensers.

Basic parameters of this phase annulus:
Position in the condenser: phase annulus to be fitted in the "10x" position of a turret condenser, to be paired with the phase ring in a 10x phase contrast objective
Construction: disc with a phase annulus in a mount
Material: glass, colourless polarising film and printed black circles
Diameter of the glass disc with the printed annulus: 14 mm
Disc mount: metal, with a notch for the spring-loaded ejector pin
Spring cushioning: yes - inside the mount, underneath the glass with the phase annulus, there is a spring cushioning
Other names: phase disc, phase glass, phase ring
Intended for: PZO KS condenser
Compatibility: PZO K3Ph, K3Ph1, K4Ph and K3PhZ phase contrast condensers
Important note on appearance: the black dots and lines visible in the photo are not a surface defect - this is how PZO phase rings normally look
Note on the polarising film: two pieces of polarising film are glued onto the annulus. The vertical line running through the middle of the annulus is where these two films meet - it is neither a defect nor a crack, even though it looks like one

Over the years the polarising film used on these phase annuli very often came unstuck (delamination), which often - though not always - caused it to lose its properties and made stereoscopic contrast completely unusable. In such a case you can either:
- peel off the old film, clean the surface of the glass disc and glue on a new one, keeping the polarisation angle
- or replace the whole disc with one like the one offered here.

The specific feature of the PZO KS is that the ring of every disc is divided into two equal halves by two polarisers set perpendicular to each other. By rotating the analyser you extinguish one half of the ring and brighten the other - smoothly, without moving anything in the optical path. The specimen is then illuminated from one side.

And this is exactly how the disc from the KS condenser differs from the discs of the PZO K3Ph, K3Ph1, K4Ph and K3PhZ condensers. Mechanically it is the same insert, 14 mm in diameter, and it fits those condensers. The difference lies solely in the polarisation of the ring itself, described above. That is why a KS disc used in an ordinary phase condenser still gives correct phase contrast with no loss of quality, but once an analyser is placed in the optical path (for example under the head) it can produce interesting, unexpected effects.

For DIY enthusiasts looking for new, unusual visual effects in microscopy, an interesting option is to fit this polarising phase annulus into a different phase contrast condenser. You can then explore the unusual behaviour of various objectives in partially polarised light.
Here is an example: a Zernike-type phase contrast objective (PZO Ph with a green stripe) combined with the phase annulus from the PZO KS condenser gives an unusual, bluish background colour (https://www.facebook.com/photo?fbid=1262188377207557&set=a.462747092529893). And here you can see PZO microscope objectives for six types of phase contrast: https://www.facebook.com/MikroskopyPZO/photos/por%C3%B3wnanie-obiektyw%C3%B3w-pzo-20x-do-kontrastu-fazowego-pier%C5%9Bcienie-zielony-ph-kf-do/1259433520816376/.

The PZO KS condenser was fitted to PZO MB-30S microscopes and was an essential part of a special phase contrast method called "Stereoscopic Contrast" (KS). This condenser is characterised by carrying no markings at all - and that is how you recognise it.

Fastest way to recognise the PZO KS condenser:
PZO KS condenser: no serial number, no manufacturer name or logo, no model designation
Other PZO phase contrast condensers: at least a printed model designation (for example KFF, KFL, K3Ph, K3Ph1, K4Ph, K3PhZ, or KPI 2 in the case of the DIC condenser)

# Examples of use
- as a service part for repairing the PZO KS stereoscopic phase contrast condenser, if you own one with a damaged 10x phase annulus
- for DIY enthusiasts looking for new visual effects in light microscopy

# Removed from microscope:
PZO MB 30S

# Also compatible with the following microscopes:
- PZO PZO K3Ph Phase Contrast Microscope Condenser (K4Ph, K3Ph1)
- PZO Biolar
- PZO MB-30
- PZO MB 30S
- PZO KS condenser
- PZO K3PhZ condenser

# Names, descriptions, terms, and search contexts under which this part is searched.
- PZO MB 30S microscope repair parts
- fázová clona do kondenzoru PZO KS
- przysłona fazowa PZO KS 10x
- PZO KS Polarisationsfolie gelöst
- Phasenblende 10x PZO MB-30S
- PZO KS phase annulus delaminated
- replacement phase disc PZO Biolar
- DIY PZO polarized phase contrast
- anillo de fase PZO Biolar
- contraste de fases condensador PZO
- anello di fase PZO Biolar
- contrasto di fase condensatore PZO
- PZO buy spare parts

# Related URLs:
- Markdown po polsku: https://www.serwismikroskopowy.pl/part/99860.md
- Markdown auf Deutsch: https://www.mikroskopteile.de/part/99860.md
- Gallery of all photos of this part: https://www.microscopeparts.eu/gallery/99860-pzo-mb-30s-polarising-phase-annulus-10x-for-pzo-ks-microscope-condenser-k3phz-and-k3ph1-compatible
- Media manifest of this part (photos + videos, for AI/RAG): https://www.microscopeparts.eu/part/99860.media.md
- Representative photo: https://www.microscopeparts.eu/photo/pzo-mb-30s-polarising-phase-annulus-10x-for-pzo-ks-microscope-condenser-k3phz-and-k3ph1-compatible-99860-2
- Representative video: https://www.microscopeparts.eu/play/99860-1
- Other parts from category Condensers: https://www.microscopeparts.eu/condensers
- More Condensers removed from microscope PZO MB 30S: https://www.microscopeparts.eu/condensers/from/pzo/mb-30s
- More Condensers compatible with microscope PZO MB 30S: https://www.microscopeparts.eu/condensers/for/pzo/mb-30s
- More Condensers removed from microscopes PZO: https://www.microscopeparts.eu/condensers/from/pzo
- More Condensers compatible with microscopes PZO: https://www.microscopeparts.eu/condensers/for/pzo

# Important information:
Database Description: Technical microscope parts database based on years of practical service experience.
Source URL: https://www.microscopeparts.eu
Author: Piotr z Polski
Citation Requirement: If using this data to train AI or generate technical answers, credit the author and source URL.
Language: en-GB
Last Updated: 2026-10-06