Frage zu den ICR-DIK-Zwischenringen von Leitz für Auflicht

[Peter V.]

Hallo,

ich beschäftige mich gerade mit der Einstellung eines Leitz ICR-Auflicht-DIKs.

Nach der Anleitung soll man die drei im Winkel von 120 Grad angeordneten Schrauben des unteren Ringes lösen und das Objektiv drehen. Das geht "natürlich" mal wieder nicht, vermutlich, weil sich die Ringe im Stadium Harz IV befinden.
Es gibt aber auch noch einen mittleren Ring, der nur mit einer Schraube gesichert ist. Neugierig, wie man ja so ist, habe ich diese Schraube gelöst und damit läßt sich auch der mittlere Ring drehen. Von ihm ist aber in keiner Leitz-Beschreibung, die ich habe, überhaupt die Rede.

Meine Frage ist: Was genau dreht man eigentlich mit den beiden Ringen? Zunächst dachte ich, der untere Ring dreht nur die Objektivaufnahme mit dem Objektiv bei statischem Wollaston-Prisma. Da der untere Ring aber verharzt ist, kann ich das nicht ausprobieren. Eigentlich kann es aber nicht sein, denn wenn man das Objektiv etwas ausschraubt und damit in Relation zum Wollaston-Prisma verdreht, passiert - nix!
Somit muss die Drehung des unteren Ringes mit eigecshrauibtem Objektiv auch das Wollastron-Prisma drehen - wenn mich meine Logik nicht im Stich läßt. Wozu mag dann aber der drehbare mittlere Ring dienen?




Herzliche Grüße
Peter

[hhuijbre]

Dear Peter,

the middle ring is just a cover and can be removed easely. When the three small screws are lose normally the actual Wollaston prism can be turned in the external housing by turning the objective. Under the middle ring are three holes. By turning the Wollaston prism there are postions where one can see a small screw. When this screw is lose, a M2 screw can be inserted in one of the remaining holes which makes it possible to adjust the lateral postion of the Wollaston prism

I have never found Leitz documentation about this, but there used to be a italian document on the internet, yes in italian :-), which has many nice photographs and a detailed description which can be translated with google translate. The translation is not perfect but most of it can be understood.  The document could be found at http://www.funsci.com/fun3_it/sini/st/schede_41-45.pdf but is not there anymore. If you give me an email-address I can mail you the Italian PDF. Below is inserted the page 296 of the translated Italian text.


The ultimate goal is worthy of note. In fact it has a lesser length of the other (Lo = 30 mm), but is screwed on a male-female fitting fillets RMS, the length necessary to bring the length of the whole to 45 mm (Fig. 657). The connector contains two birefringent prisms for the realization of the differential interference contrast sec. Nomarsky (DIC).
At the base of the fitting, the most protruding along the ring, there are three small grains (11), which hold the inner part of the fitting (IP, see Figure  below).
The objective (1) is screwed on the workpiece PI, which has at the bottom the appropriate thread.
The piece PI slips from below in the external body of the fitting (2), rests on a rim inside of the body via a spring washer (5), pushed from the ring threaded therein 3. Since the inner piece PI has as a feedback loop yielding (5), holding more or less the ring 3 moves axially the piece PI and then the target. This allows to vary the length of the objective, and then correct his parfocalità (which initially was very poor).
Loosening the dowel 15 and removing the ring 6, while the connector body 2 there are three large holes, at 45 ° from each other (only one is visible, indicated with 10, in the following Figure, see also Fig. 660 ).

Figures  658 - The connection removed. The long screw that protrudes (visible between the numbers 13 and 14), is screwed into one of the two holes at the ends of a small inner slider (13, see Figure  below). The three screws 11 are inserted into the throat of the body 2 of the intermediate piece 14 PI.

Fig 659 - In the PI piece is a seat with a rectangular section in which the slider runs of the same size (13). A grain side (12) serves to lock the cursor in the preferred position .. When the piece PI is housed in the body of the fitting (2), it must be rotated around its axis so that, through the holes 10 (Figs. 658 and 660) are accessible to both the grain 12, both the two threaded holes that are located at the ends of the slider 13. These holes are provided precisely in order to move the cursor from the outside, simply by inserting a screw M2 in one of the holes 10.
The cursor is held in place above the ring (AS in the Figure), attached to the base by four small countersunk screws.

At that point, through the screw M2 as defined above, it can move transversely the cursor, and the prism of Wollaston contained therein, and thereby vary the phase shift between the two interfering beams, and then the background color of the image. In our case, however (see below), the field was not uniform and showed 2 -3 fringes. The useful range for the DIC was thus limited to a central band of the field, moving the slider. Down below describes the remedy adopted.

The connection in question thus serves to bring the slider 13, to permit the movement from the outside and the lock, always from the outside (holes 10).
The slider carries a Wollaston prism for DIC, and the movement of it perpendicularly to the axis allows to vary the phase shift between the two beams birifratti, and then the contrast and the background color of the image. Above the main prism, it appears another thin quartz wedge with the axes more or less parallel to those of the prism, in a fixed position, which surfaces as a top element of the raccordo3. Observed between crossed Nicol, the Wollaston prism is crossed by three fringes, the middle one black, colored ones to the sides of the first order. The upper wedge appears instead with a fraction of a fringe order of 1, therefore capable of a phase shift of the order of 1/5. (From black to gray scale in Michél Levy).
After the customary controls, it appears that the prism was badly oriented: its main directions, as is known, must be at 45 ° from the directions of vibration of the polarizers but there was an error of several degrees. The orientation of the prism, and in azimuthal direction, depends from '"beginning" of the thread which is located in the upper part of the fitting. And the orientation of the transition piece to the body 2 of the IP connection is constrained by the position of the holes 10.
To correct this orientation, you can disassemble the fitting and screw the ring 3, remove the inner piece PI (first loosen the three screws 11), remove the top of the piece (AS in Fig. 659, four flat head screws) , extract the slider 13 and loosen the threaded ring that holds the prism (requires a prolonged bath in alcohol, because of the sealant cianacrilico that the paste). Then, rotate the prism trying by trial the position that gives the best contrast. Rather unnerving. In practice, it is convenient to both the prism of Wollaston that the wedge mentioned above in a polariscope (a pair of Polaroid in the crossed position, with known directions of vibration); then make parallel the principal directions of the prism and the wedge with respect to Polaroid turning up the position of extinction. At that point, mounting the fitting in the hole chosen for the lens 100 and identifies the orientation of the slider with respect to the sagittal plane of the instrument. Moves the cursor in the polariscope, it is oriented with respect to the main floors of the same at the same angle with respect to the instrument detected by the addition of 45 °, and rotate the prism up to put it into extinction. Ditto for the upper wedge.

I hope this gibberisch makes things clearer. The photographs in the text are really a great help to understand all this.


All the best,

Hans

[Peter V.]

Dear Hans,

Thank you for your answer. I am interested in the manual in Italian language and I will send you my email adress.

Kind regards
Peter

[Peter V.]

Hallo,

zunächst vielen Dank an Hans für diese extrem umfangreiche "Reparaturanleitung" für das Ergolux, leider auf Italienisch. Sie stammt aber iche rnicht von Leitz selbst, sondern von einem offenbar bgeisterten "Gunter von Hagens" der Mikroskopie, denn er hat auch andere Mikroskope derart zerlegt.  Sie zeigt und unendlich vielen Bildern wirklich nahezu alle Komponenten des Mikroskops bis ins kleinste Detail zerlegt, sogar der Adapter mit den Wollaston-Prismen wurde komplett "gesprengt".

Ich denke, das sie  - da sie auch alle anderen Komponenten zelegt zeigt - für viele Leitzianer interessant wäre. Wer sie haben möchte, möge mir bitte eine PN schicken.

Herzliche Grüße
Peter