Focus unit; S_M_D

For technicians and partly for sales managers!

 

 

 

 

 

These instructions describe the procedures to install and adjust the focus unit for SCAN 150, Pannoramic SCAN, Pannoramic MIDI and Pannoramic DESK scanners (S_M_D).

To help resolve problems with the focus unit a hardware description of the implemented components and adjustment procedures are added.

 

 

The focus unit is designed to fulfill the following tasks

·       Holding the objectives Plan-APOCHROMAT 20x/0.8 or Plan-APOCHROMAT 40x/0.95 in the center of the focus range

·       Focusing of tissues during the scan process on slides with a slide thickness of 1.0mm nominal

·       Concentrating the illumination light to the field of view (FOV) during brightfield scan procedures

·       Insuring a dark background during fluorescent scan procedures

 

General

Functional overview

            Principle of focusing

Components and construction

Shutter mechanics

            Principle of shutter mechanics

            Hardware limits and shutter on or off

Adjustment procedures

            Adjust the ex-center position

            Find the hardware limits

            Mount the objective

            Adjust the objective position

            Adjust the condenser position

Dismount or mount the focus unit

 

 

 

For safety regulations regarding human health and scanner functionality please refer to:   Precautions

 

 

 

 

General

 

The described focus unit is a component of the Pannoramic scanner family and contains the following main parts:

·       The focusing part  (driven by the focus stepper motor)

·       The objective with mounting nut and objective position fixing

·       The condenser with its position fixing

·       The focusing mechanics (Ex-center, 8:1 divider, Focus pin)

·       The shutter mechanics (Shutter arm, shutter wire, shutter guide)

 

The focus unit gives the possibility of focusing the FOV (field of view, seen by the scan camera) automatically during the scan process of the sample.

 

The unit was developed for the use of objectives of the following types:

 

Plan-APOCHROMAT 20x/0.8      and     Plan-APOCHROMAT 40x/0.95

 

The objective type “Plan-Apochromat” contains several, special chromatically and spherically corrections and delivers so an image of very high color trueness with very small spherical aberration.

 

If the mechanical dimensions do not exceed the size of the Plan-APOCHROMAT 40x0.95 type objective, the mechanical mounting is identical and the focus distance of the objective to the tissue is not closer then 0.25mm, other kind of objectives can be used also but it is strongly not recommended!

 

·       Always check with 3DHISTECH first when a different objective should be used!

 

The shutter mechanics covers the condenser and this way, during fluoresce scan sessions, the bright field illumination path is broken. The two commands, condenser cover off and condenser cover on are identical with the physical lower and upper limits of the focus unit.

 

The exchange of the focus unit is possible

            - If the stepper motor or its electronics for the focus unit is faulty

            - If the shape of any part is deformed or a part is broken.

            - If the focus unit has any fault and you are unable to fix it.

 

 

Requirements

 

 

Attention:           Do not mix the versions of SlideScanner.exe and SlideScannerService.exe! Always use these programs with the same version number; otherwise the SlideScannerService.exe program could produce unwanted results and SlideScanner.exe does not work correctly or even freeze!

 

 

 

 

 

 

 

 

Focus unit with objective changer

 

The focus unit with objective changer (Focus unit OC) is a newly developed component for Pannoramic SCAN and MIDI type scanners and is implemented since February 2014.

The unit is a combination of the focus part as shown above (Focus unit S_M_D) and this is equipped with the objective changer unit as used in the P250.

 

·      The unit can be used only in the SCAN and MIDI type scanners for scanning slides with a slide thickness of 1.05mm maximal.

·      Connect the Turret cable of the SCAN or the MIDI to the connector “OC control” and connect the cable “Turret control” to the turret unit.

·      If the scanner is equipped with an objective changer unit, the name “Modular MIDI” and “Modular SCAN” is used.

 

Features

 

The user is able to use different magnifications consecutively for the brightfield and the fluorescent scan procedure likewise,

 

·      Without manual objective exchange.

·      Without additional objective position adjustments.

·      Without additional optical and illumination adjustments.

·      Focusing principle and unit limits are the same as in the “Focus unit S_M_D”

·      Shutter principle and construction is the same as described for the “Focus unit S_M_D”

·      Exchange of the objective is software controlled and possible between 2 slide scan sessions.

 

Once, the objective settings are defined in the dialog “Microscope Settings” these must not be changed or modified until the objective(s) will be exchanged physically.

 

       Objective changer”; “Configure the scanner”, “Service Program

 

·      For focusing and shutter relevant components and construction please refer to this description (in front of you)

·      For objective change relevant components and construction please refer to the “Objective changer part” of the description “Objective changer for P250”

 

 

 

                   Functional overview

 

Physically, the focus position is defined by the distance of the objective to the tissue. If the tissue is in the focus of the objective, a sharp picture is seen by the camera. Because the tissues are different from each other in thickness and the thickness can change inside the same tissue also, the focus position must be checked and corrected always, during scanning.

 

Furthermore, if the slide will be changed, the specimen holder must be moved away from the objective to avoid collision.

 

If the shutter is changed from shutter off to shutter on, the specimen holder is moved to a position where the focus pin is not in connection with the specimen holder.

During all these actions, except focusing, the objective must be protected against touching and the focus pin as well as the 8:1 divider must be protected against overstraining. This is realized by the focus unit, with the different positions of the focus pin and the positions of the specimen holder; mounted on the X-Y-stage.

 

 

Working distances

 

As you can see, the gaps between cover slip and objective are very small, especially if the objective Plan-APOCHROMAT 40x/0.95 is used.

The worst case for focusing is defined by the parameters of the 40x objective.

 

Objective position

 

Because the objective in Pannoramic type scanners is mounted in the nominal focus position, so we have to move the tissue toward the objective or away from it to find the real focus. It is very important, that the objective position is adjusted well; otherwise, if the objective focus position does not match the focus range, offered by the focus pin movement range, a sharp camera image can never be produced. 

 

      

Carl Zeiss GmbH:    Plan-APOCHROMAT 20x/0.8 and Plan-APOCHROMAT 40x/0.95

 

                                               Objectives from Carl Zeiss          local PDF-file; Product information

 

 

 

Scale on the 40x objective

On the scale of the 40x objective, the thickness of the cover slip should be selected. If the real thickness of the cover slip differs from the selected or adjusted value, the quality of the scanned FOV may be reduced; resulting in poor contrast and bad resolution! This may also occur if the thickness of the cover slip is adjusted correct and the tissue is too thick or the thickness of the tissue varies too much!

 

 

       Spherical aberration        Wikipedia

 

 

 

 

 

Objective position

 

In Pannoramic type scanners the objective is mounted into the middle of the focus range, offered by the movement limits of the focus pin during focusing.

 

  • It is very important, that the objective position is adjusted well; otherwise, if the objective position does not match the focus range, offered by the focus pin movement range, a focused camera image can never be produced!
  • Because the slide thickness can vary from 0.95 to 1.05 mm, the thickness of the slide, used to adjust the objective position, is also important during the objective position adjustment.

 

       Adjust the objective position”. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                   Principle of focusing

 

The slide is hold in the specimen holder. To achieve a parallel movement of the slide in relation to the objective, the specimen holding mechanics contains a parallelogram. This guarantees the position of the tissue to be always perpendicular to the optical axis. The specimen holder has a mechanical preload, so the slide has always a connection to the focus pin during scanning.

 

The focus pin is moved by a stepper motor via an ex-center and an 8:1 divider. The resolution of the stepper motor with 3200steps per revolution, the characteristics of the ex-center and the 8:1 divider allows a very fine resolution of the focus steps and so tissue focusing.

 

Focusing algorithm

 

The focus position of the FOV is found, if the camera sees a sharp image. To reach this, the scan camera takes images in different positions of the entire focus range and the software finds the best focus range. When this range is found the real focus position is found by iteration of the interval.

 

       Specimen holders”, “Parallelogram”, “Stepper motor

 

 

 

 

Home1,2

 

The Home position of the entire mechanics is situated outside the focus range and is always found within Home1 and Home2. The counting of the ex-center motor steps starts after a Home1,2 execution.

 

       Stepper motor implementation”; and “Sensors Home1,2

 

Focus range

 

The step number of the stepper motor is identical with the actual focus position and this is displayed by the software. The entire focus range in S_M_D scanners is 800 steps, counted from 1200 to 2000. Its true, that the focus of the tissue is reached at the positions Home1,2, 1600 steps and 3200 steps, but the center of the nominal focus range is defined at the position 1600 steps.

 

 

       Hardware limits and shutter on or off

 

 

 

 

Nominal focus position

 

Pre-calculated values for slide thicknesses

Slide thickness [mm]

Focus position [steps]

1.05

1350

1.00

1600

0.95

1850

Because the specimen holder of S_M_D type scanners can hold slides with a thickness of 0.95 to 1.05 mm the nominal focus position is defined by 1600 steps for a slide thickness of 1.00mm. If the slide thickness used to adjust the objective position deviates from the nominal thickness, please set the focus unit motor to the relevant step number, depending on the used slide thickness. The objective position should be adjusted at the relevant focus position.

 

  • Measure the thickness of the slide (but without the cover slip) with tissue to be used; use the caliper.

 

·      If the thickness of the slide deviates from 1.00mm, calculate the focus position. A deviation in thickness of 0.01mm results in a deviation of 50 motor steps.

·      Insert the measured slide into the specimen holder and set the appropriate (calculated) focus position in the live view of the program SlideScanner.exe.

·      Adjust the objective position to the preset focus position until a focused image can be seen in the live view.

 

 

Scan area

 

The scan area defines the part of the slide on which the tissue, scanned by the scan camera, is expected to be. The entire scan area is captured by the preview camera in three sections and is shown in the preview area of the program SlideScanner.exe.

The scan area is limited by the mechanical construction of the specimen holder and should be defined as large as possible; it is not defined in relation to the cover slip.

In all cases, the specimen holder should never be touched by the focus pin or the objective! In other words, the scan area is that area of the slide, on which the focus pin and the objective (especially 40x magnification) can be moved seemingly during scanning the tissues, without touching the specimen holder.

 

 

 

Exchange of the objective

 

As mentioned before, the focus unit may be equipped with a 20x or a 40x objective. Because the focus position of the 40x objective is very close to the tissue, the scan area, defined for the 20x objective is no longer valid, to avoid collision of the objective with the specimen holder.

If the objective will be changed from a 20x to a 40x magnification, the scan area must be defined again and therefore the preview calibration must be executed again also. During defining the scan area for the 40x objective, the position of the focus pin and the position of the objective pupil should be checked to avoid touching of the specimen holder! Adjust the limits in the nominal focus position!

If the objective is changed from the 40x to a 20x magnification it is not bound to define the scan area again, if the smaller area can be accepted. In all cases, if the scan area was modified, a preview calibration is bound to do.

 

       Working distances” and “How to exchange the objective in SCAN, MIDI and DESK

 

Physical construction of the specimen holders

 

Because the physical holding of the slide is different in all three scanner types, the scan area values are different also and they vary from scanner to scanner of the same type also (mechanical tolerances).

In all cases, the scan area values of X-min, X-max, Y-min and Y-max are set just before the focus pin or the objective touches the specimen holder. The accuracy of the limits is 100 steps.

 

       Specimen holders

 

Pannoramic SCAN

 

The slide is hold by the specimen holder on the longer, lower edge and with a slide clamp on its upper edge, on the barcode area; see the red lines on the right. As you can see, the definition of the limits X-min and Y-max are critical. X-max and Y-min are given by the maximal usable slide size and are not critical; they could be the slide edge.

 

       Specimen holder”, “Areas of the slide”, “Scan area” and “Define the scan area

 

 

 

 

 

 

 

Pannoramic MIDI

 

The slide is hold in the specimen holder with the help of three slide studs, situated on the longer edges as shown.

The surrounding of the slide stud is left out automatically from the scan process since the software version 1.14 and needs not to be excluded manually from the scan area.

 

IMPORTANT

·       Never cross the slide stud with the focus pin or the objective!

 

 

       Specimen holder”, “Areas of the slide”, “Scan area” and “Define the scan area

 

 

 

 

 

Pannoramic DESK

 

The slide is hold in the specimen holder by the help of one slide stud on the shorter, inner edge and by the lock handle on the outer, shorter edge. Furthermore, along the longer edges of the slide there are leading rails situated to lead the slide during slide insertion. All this facts should be taken into account if the scan area is defined. The surrounding of the slide stud is left out automatically from the scan process since the software version 1.14 and needs not to be excluded manually from the scan area. If you are working with the service program take care of the focus pin and the objective.

 

IMPORTANT

·       Never cross the slide stud with the focus pin or the objective!

 

       Specimen holder”, “Areas of the slide”, “Scan area” and “Define the scan area

 

 

 

 

 

 

Configure the Scanner

 

 

·      Since the software version 1.18 the MIDI OC and SCAN OC scanners are requiring configuration parameters.

 

Modular MIDI;        (MIDI OC)

 

[Microscope];                                                                                  Modular MIDI

SerialNumber=PMIDI-032101;                                                    Serial number of the scanner

MicroscopeType=3DMic10;                                                         MIDI OC

ScanCameraType=Hitachi_HV_F22CL;                                               not used, not defined here

PreviewCameraType=CVrmc_m8_pPro;                                  Preview camera type

BarcodeReaderType=PreviewCamera;                                     Barcode capturing is done by the preview camera

LoaderType=SL_1Mag_12Slide_Sensor_Horizontal;                        Slides are hold in the tray with 12 bays and slide sensor used

CameraChangerType=CC_None;                                             Camera_chancher_VT not present

ReflectorTurretType=RT_3DH_10Pos_Gears;                         Gear driven RTU present

BrightfieldLightSourceType=BLS_Halogen_5W;                    FOV Brightfield illumination done by a 5W halogen lamp

ObjectiveChangerType=OC_2Pos;                                        Objective changer type with 2 objective positions present

ObjectGuideXYZType=OGXYZ_1.0mm;                                   The specimen holder can hold slides with a thickness of 1.0mm nominal

FlashUnitType=NoFlashUnit                                                      Flash illumination unit not present

NDFilterType=ND_None;                                                             ND filter unit not present

PreviewLightType=PreviewLightUnitType_Type3;                 Preview illumination BF only

PowerSwitchBoardType=PowerSwitchBoard_None;             Power distribution and switch electronics not present

 

Following sections and parameters are also implemented

 

[Focus]
NoFocusPinOnTheObjectHolderX=26000
NoFocusPinOnTheObjectHolderY=18000

 

 

[ObjectiveChanger]
ObjectiveChangerTimeout=7000

 

       If MIDI OC:                MicroscopeConfiguration.txt

 

                        Handling the *.ini files”; “Service Program

 

 

Modular SCAN;       (SCAN OC)

 

       Configure the magazine unit” and “Magnet disc

 

 

[Microscope];                                                                                   
MicroscopeType=3DMic11;                                                          Modular SCAN
LoaderType=SL_6Mag_25Slide_NoSensor_Vertical_2;        Magazine unit 
CameraChangerType=CC_None
ReflectorTurretType=RT_3DH_10Pos_Gears
BrightfieldLightSourceType=BLS_Halogen_5W
ObjectiveChangerType=OC_2Pos
ObjectGuideXYZType=OGXYZ_1.0mm
FlashUnitType=NoFlashUnit
NDFilterType=ND_None
PreviewLightType=PreviewLightUnitType_Type3
PowerSwitchBoardType=PowerSwitchBoard_None

 

Following sections and parameters are also implemented!

 

[Focus]
NoFocusPinOnTheObjectHolderX=29600
NoFocusPinOnTheObjectHolderY=18000

 

 

[ObjectiveChanger]
ObjectiveChangerTimeout=7000

 

       If SCAN OC:             MicroscopeConfiguration.txt

 

                        Handling the *.ini files”; “Service Program

           

 

 

Components; construction

 

Stepper motor

Ex-center and focus plate

Focus plate and 8:1 divider

8:1 divider and focus pin

Objective mounting

Cover tube

Condenser and mounting

 

 

                   Stepper motor

The drive of the focus unit is realized with a 2-phase stepper motor and has a resolution of 3200µ-steps/revolution and drives:

·       the focusing part via the ex-center, the 8:1 divider and the focus pin (see “Principle of focusing”) and

·       the shutter guide via the shutter arm and the shutter wire (see “Principle of shutter mechanics”).

 

The forward direction of the motor’s axle is counter clock wise, CCW . The command and status information for the focus unit like step number and direction; go to Home1,2 or go to shutter on or shutter off are received from the stepper motor’s electronics via the cable STX-3 (X stands for the actual hardware version and depends on the scanner type also).

 

·       The address of the focus motor in S_M_D is always 05.

 

·       The parts and units of the stepper motors need neither maintenance nor mechanical adjustments.

 

       Stepper motor”, “Addresses”, “Cabling of addressable units” and “USB-controller cabling

 

 

 

 

 

 

 

 

 

 

 

                   Ex-center and focus plate

 

The motor axle of the stepper motor rotates the ex-center on which the focus plate is mounted and this moves the 8:1 divider.

 

·       The ex-center position is correct, if 1600 focus steps are moved and the shutter arm stays in the middle of the slot. If this condition is not met, please adjust the ex-center position more precise (maximal tolerance is 10steps).

 

 

Attention

The mountings of the focus plate should not be loosened; here the position of the focus plate and so the position of the 8:1 divider and the position of the focus pin is adjusted!

Because the movement range of the focus pin is very small, the adjustment of the focus pin position is delicate; the focus plate mounting bolts position must not be altered.

 

·       The adjustment of the focus pin position requires special adjustment tools!

 

 

 

 

 

 

 

 

 

 

 

Furthermore, on the ex-center mounting the shutter arm is situated for the shutter off and on operation. This defines in the same time, together with the shutter wire the hardware limit for the focus unit.

 

 

 

 

 

 

 

 

 

 

 

 

                   Focus plate and 8:1 divider

The connection between focus plate and divider is realized with a ball-headed joining because the ex-center does an up-down and additionally a left-right movement.

 

·       The use of the compression spring ensures a hysteresis-free connection.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

·       The bearing of the 8:1 divider and the ball-headed pin of the focus plate eliminates the unwanted left and right movement.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                   8:1 divider and focus pin

 

On the other end of the 8:1 divider the focus pin is realized. The focusing of the tissue is done by moving the focus pin (and so the tissue) toward or away from the objective. Because the focus pin touches the slide always during focusing, the distance of the slide with tissue to the objective is modified until the focus position is found. The mechanical construction allows a focus pin movement of 0.144 mm around the nominal focus position during focusing (focus range from 1200 – 2000 steps); this means a movement of 0.288 mm over all (from 800 – 2400 steps) can be done.

 

 

 

 

 

 

 

 

 

 

 

 

                   Objective mounting

 

Adjust the objective position so that the tissue is in focus while the nominal software focus position is selected by the software (1600 focus steps).

 

·    The objective nut can be screwed if the fixing bolt is loosened.

 

·    To mount or exchange the objective, remove the objective nut, mount or exchange the objective, insert the objective nut again and adjust the objective position!

 

·    By rotating the objective nut with barely loosened fixing bolt the objective position will be modified and so adjusted.

 

·    Tighten the fixing bolt so, that the position of the knurled objective nut can even not be modified manually.

 

·    To exchange the objective, please refer to the appropriate chapter in the folder “How to exchange …

 

 

       Working distances” and “Exchange the objective SCAN, MIDI, DESK

 

Carl Zeiss GmbH:    Plan-APOCHROMAT 20x/0.8 and Plan-APOCHROMAT 40x/0.95

 

                                               Objectives from Carl Zeiss          ©Carl ZEISS GmbH; stored PDF-file; Product information

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                   Cover tube

 

·    The image path cover tube exists in two versions; depending on the existence of the turret unit, whether the shorter or the longer tube is used.

·    The shorter cover tube is mounted directly onto the objective nut, in opposite of the objective.

·    The longer cover tube is used if the turret unit is not implemented and is mounted into the camera tube mounting; on the opposite side of the camera tube.

·    The image path cover tube is used in the SCAN and the MIDI only; in the DESK a cover tube is not required.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                   Condenser

The condenser concentrates the incoming light to the field of view (FOV).

Because the size of the illuminated part of the tissue is critical, the condenser position can be adjusted; the focus position is 10.9mm nominal.

 

       Condenser              Wikipedia

                  condenser position adjustment.

                 

 

·         Maintenance is not required

 

 

 

 

 

 

 

 

 

 

Condenser and mounting

 

In early developed scanners (MIRAX SCAN), the condenser position was adjusted by shifting it toward or away from the tissue, so the correct condenser position could be found.

 

Because in the SCAN the condenser is arranged in horizontal position, it is an acceptable and cost-effective solution.

 

In the DESK and the MIDI, in opposite to the SCAN, the condenser is arranged in vertical position. In this case, if the mounting bolt is loosened and the condenser moves easily in its mounting, the condenser may falling out of the mounting and might damage the illumination mirror of the DESK or the MIDI.

 

To resolve this problem, the condenser got a thread part. The early developed version can be found in scanners, delivered until the end of the year 2009.

Important

·       If an early developed solution is used in the DESK or the MIDI, please protect the illumination mirror by inserting a slide between scanner plate and focus unit if the fixing bolt will be loosened or protect the condenser otherwise against falling out.

 

 

 

 

 

 

 

·       The condensers are both from the same type; there are no differences in the construction of the optics.

 

 

 

·       In the adjusted condenser position, the condenser housing looks only a little bit over the mounting.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Shutter mechanics

 

The mechanical shutter is implemented as a part of the focus unit and the shutter guide is situated between condenser and 8:1 divider.

 

During fluorescent scan the shutter must be closed and insures so a dark background. Other, unwanted fluorescent materials (e.g. painting, optics) can not reflect the fluorescent light or can not fluoresce and so they will not disturb the fluorescent view.

 

During bright field illumination the shutter must be fully open to ensure a bright and evenly illumination of the FOV.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                   Principle of shutter mechanics

 

The shutter has only two usable states, shutter on and shutter off. These positions are identical with the hardware limits of the focus unit; in these positions the bright field illumination (the condenser) should be fully opened or fully closed respectively. All other possible positions of the shutter are not defined, therefore faulty positions and not allowed during the scan process.

 

 

 

 

 

 

 

 

 

 

 

 

Shutter arm position

 

During rotation of the stepper motor axle in direction to the negative limit of the focus unit, the shutter wire will be touched by the shutter arm and is so moved to the shutter off state (bright field illumination allowed). If the stepper motor axle is rotated in direction to the positive limit, the shutter arm will touch the shutter wire from the opposite direction and moves it so to the shutter on position (bright field illumination disabled).

In practice it means, that the shutter wire together with the shutter arm is the limiter of the focus mechanics and with this limiter the shutter on and shutter off option is realized.

 

·       During focusing the shutter wire will never be touched by the shutter arm.

 

 

 

 

 

 

 

Shutter guide position

 

A = Focus pin

B = Shutter guide

C = Shutter wire

D = Condenser

E = Condenser fixing

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

If the shutter wire is touched by the shutter arm, the torsion is transmitted via the shutter wire to the slider of the shutter guide. The slider brings so the shutter guide into the proper position.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Shutter on or off and hardware limits

 

The hardware limits will be reached only during shutter on (CondenserCoverOn = Light path closed; fluoresce scan) or the shutter off (CondenserCoverOff = Light path opened; bright field scan) procedure. The limits are defined without lost steps; they may differ by some ten steps from unit to unit, the reason is the tolerances of the components and the found ex-center position in relation to the motor axle.

 

 

 

       How to define hardware limits” and “Find the hardware limits for the focus unit

 

 

 

 

 

 

 

 

 

 

 

Adjustment procedures

 

 

The following procedures are described especially for Pannoramic SCAN. In Pannoramic MIDI and Pannoramic DESK the adjustments are logically identical, but some terms like “up, down, top, bottom, left, right, horizontal and vertical” differ. Please take this into account if you are adjusting the DESK or the MIDI. The term “S_M_D” stands for SCAN, MIDI and DESK.

 

 

 

                   Adjust ex-center position

 

This adjustment must be done only if the ex-center was dismounted or the fixing bolt was loosened. With this adjustment the focus position is set to be +1600 steps nominal.

·       Because in this position the fixing bolt can not be reached, we use the focus position of 2400 steps for this adjustment.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1.      With the service program set the focus unit to Home1,2.

 

 

2.      Go forward to the focus motor position 2400 steps.

 

 

3.      Loosen the ex-center fixing bolt barely, so that the ex-center can be moved and rotated on the rotor axle.

 

 

4.      Set the focus unit to Home1,2.

 

 

5.      Go forward to the focus motor position 2400 steps again.

 

 

 

6.      Bring the shutter arm manually into the vertical position (the shutter arm shows downward and the fixing bolt shows upward). Before you are tighten the ex-center fixing bolt please check the position of the shutter arm in relation to the shutter wire also.

 

·       The shutter arm should touch the shutter wire nearly in the middle of the hook. To reach this, bring the ex-center in proper position on the motor axle and tighten the fixing bolt.

 

7.      Go to the focus motor position -300 steps and check the position of the shutter arm in relation to the shutter wire’s hook. If the shutter arm touches the shutter wire from beside or the position of the shutter arm in relation to the shutter wire is unacceptable, repeat from step 1.

 

8.      Go to the positions Home1,2.

 

 

 

 

 

 

 

 

 

 

 

9.      Go forward to the focus motor position +800 steps.

 

10.  In this position the shutter arm should show exactly upwards. A deviation of approx. 10 steps from the vertical direction is maximal allowed. If the deviation is too much, repeat the adjustment from step 1.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

·       The ex-center position is correct, if 1600 focus steps are moved and the shutter arm stays in the middle of the slot. If this condition is not met, please adjust the ex-center position more precise (maximal tolerance is 10 steps).

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                   Find the hardware limits for the focus unit

 

This procedure must be done only if the ex-center was dismounted or its fixing bolt was loosened. Before the following procedure is done, the previous adjustment “Adjust the ex-center position” should be correct.

 

       How to define hardware limits

 

 

Find the negative limit

 

11.  Set the focus unit to Home1,2.

 

12.  Go forward to the focus motor position -300 steps and check the position of the shutter arm in relation to the shutter wire. If the shutter wire touches the shutter wire from beside or the position of the shutter arm in relation to the shutter wire is unacceptable, repeat the previous step, Adjust the ex-center position

 

13.  Go backward +300 steps.

 

14.  Press Home1 (only). There should be not more then +-2 steps difference to Home1.

If there are more steps lost, decrease the actual number of steps by 10 and repeat from step11. In the steps 12 and 13 use the actual number of steps!

 

15.  If there are not more then 2 steps difference to Home 1, increase the number of steps by 10 and repeat from step 11. In the steps 12 and 13 use the actual number of steps!

 

16.  The negative limit is found correctly if the motor movement has no steps lost and the actual number of steps, increased by 10 would produce lost steps.

The found negative limit can differ by more ten steps from unit to unit. The reasons are the tolerances of the components and the used position of the ex-center in relation to the motor axle.

 

17.  The negative limit is found correctly if the motor movement has no steps lost and the actual number of steps, increased by 10 would produce lost steps.

The found negative limit can differ by more ten steps from unit to unit. The reasons are the tolerances of the components and the used position of the ex-center in relation to the motor axle.

 

18.  Update the parameter value of the parameter “FocusDeviceMin” with the found number of the actual steps in the file “MicroscopeConfiguration.ini” section [HardwareLimits].

 

19.  Update the parameter value of the parameter “CondenserCoverOff” with the found value in the file “MicroscopeConfiguration.ini” section [Focus].

 

 

Find the positive limit

 

20.  Set the focus unit to Home1,2.

 

21.  Go forward to the focus motor position +3550 steps.

 

22.  Go backward 3550 steps.

 

23.  Press Home1 (only). There should be not more then +-2 steps difference to Home1.

If there are more steps lost, decrease the actual number of steps by 10 and repeat from step 19. In the steps 20 and 21 use the actual number of steps!

 

24.  If there are not more then 2 steps difference to Home1, increase the number of steps by 10 and repeat from step 19. In the steps 20 and 21 use the actual number of steps!

 

25.  The positive limit is found correctly if the rotor movement has no steps lost (max. 2 steps) and the actual number of steps, increased by 10 would produce lost steps.

The found positive limit can differ by more ten steps from unit to unit. The reasons are the tolerances of the components and the used position of the ex-center in relation to the motor axle.

 

26.  Update the parameter value of the parameter “FocusDeviceMax” with the found value in the file “MicroscopeConfiguration.ini  section [HardwareLimits].

 

27.  Update the parameter value of the parameter “CondenserCoverOn” with the found value in the file “MicroscopeConfiguration.ini” section [Focus].

 

 

                   Mount the objective

·       To exchange the objective, please see also “Objective mounting

 

1.      Disconnect the cable from the focus unit.

 

2.      Remove the focus unit.

 

3.      Loosen the objective fixing and remove the objective mounting and holding nut.

 

4.      Mount the objective. Hold the mounting nut with one hand and tighten the objective by manually with the other hand.

 

5.      Drive in the objective holding nut into the focus unit.

 

6.      Adjust the distance of the objective to the plane of the focus pin until a gap of approx. 3-4 mm is reached. This prevents the objective against touching the specimen holder during mounting the focus unit at the first time.

 

7.      Mount the focus unit  and connect the cable.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

                   Adjust the objective position

 

This adjustment assumes that the focus mechanics is fully is adjusted, except the objective position.

 

·       Important for this adjustment is a slide with a thickness of 1.0mm (measured with the caliper and without cover slip) and the focus position of a tissue part must be known; otherwise, the following adjustment will be incorrect; outside the tolerance!

 

1.      Start the slide scanner program, insert a slide with a tissue (the real focus position of the tissue should be known) and create a live view; the known focus position of the tissue should be near to 1600 steps, the nominal focus position.

 

2.      Produce a live view and set the focus motor position to the known focus position (or 1600 steps).

 

3.      Loosen the objective mounting nut barely by loosening the objective fixing bolt.

 

4.      Drive the knurled objective nut so, that the objective moves toward the tissue or away from it until the focus is found.

 

5.      During tightening the fixing bolt of the objective, observe the live view and correct the objective position as necessary.

 

6.      Check the adjustment with the option “Auto focus”; a tolerance of 25 focus steps to the known focus position is allowed.

 

7.      Repeat from step 2 if necessary.

 

8.      Check the focus position with tissues, different in thickness. The focus position of the thickest (muscle) and thinnest (blood) tissue should be always inside the focus range from 1200 to 2000steps!

 

       Objective mounting”,

 

 

 

 

 

 

 

                            Adjust the condenser position

The adjustment of the condenser is important for the bright, uniform and optimal illumination of the FOV. This reduces so the exposure time of the camera and increases the quality of the scanned tissue. If the objective position was modified, the correctness of the condenser position has to be checked again!

 

·       This adjustment assumes that the entire focus unit is adjusted and the correct objective position is found; this should be always the last adjustment of the focus unit.

 

       Condenser and mounting

 

1.      Create a live view with the scan camera in the focus tab and set the focus motor position to 1600 steps.

 

2.      With the preview positioning tool  find a “clean” FOV outside the tissue and inside the cover slip, without dust.

 

3.      Loosen the condenser’s fixing bolt.

 

 

4.      Rotate the condenser toward to the objective, to find the start position for the adjustment; the brightness will increase.

 

 

 

 

 

 

5.      Rotate the condenser in opposite direction and look at the live view. Beware of the condenser cover (mechanical shutter), don’t close it and don’t bend it. You will see two surfaces (from the diffuser) coming into focus (see “Condenser 1 and 2”). While rotating the condenser you can also observe that the brightness decreases.

 

 

 

6.      After the second surface just disappeared (Condenser 2) and the live image is smooth and bright (“Condenser position”), stop moving the condenser and tighten its fixing bolt (the image was done with previously adjusted illumination. If you are starting the adjustment, the figure “Condenser position” might be is not so smooth).

 

 

7.      If the brightness decreased too much, repeat from step 3.

 

 

 

 

 

 

 

 

 

 

 

Check the shutter closed position

 

·    During a fluorescent FOV is visible on the screen as a live view, switch on and off the bright field illumination several times with the service program. If the shutter is in proper position the brightness of the view must not change.

 

 

 

Check the shutter open position

 

·    During LUT-adjustment the FOV is visible on the screen as a live view. Try to bring the shutter wire manually more into the shutter off position (the -300 limit) and observe the screen. If the shutter is in proper position the view of the LUT adjustment must not change.

 

Remark

In the DESK, the shutter closed position (fluorescent scan mode) will never be used, but check always the “Shutter open” position!

·      If the illumination path is partially cut by the incorrect shutter position, an evenly illumination of the FOV will never be reached! This is true for all scanner types also.

 

 

 

 

 

 

Dismount or mount the focus unit

 

Focus unit mounting

 

In previously developed SCAN, MIDI and DESK scanners a solution with a worm bolt for the focus unit mounting was used. In this cases, drive the bolt as usually counter clockwise to loosen and clockwise to tighten it.

 

In newer scanner types the focus unit and the X-Y-stage are fixed with a dovetail solution. In this case, opposite as usual, drive the mounting bolt clockwise to loosen and counter clockwise to tighten the fixing.

 

If the X-Y-Stage is in the home position, the focus unit can not be removed; therefore step 1 must be always done before the focus unit will be removed or inserted and the X-Y-stage is in home position.

 

              Scanner plate” and “Dovetail fixing

 

 

 

 

 

 

 

 

 

 

 

 

Dismount the focus unit

1.      With the service program go forward to the position 10,000 steps in +X direction (3 revolutions of the motor axle).

 

2.      Disconnect the cable of the focus unit.

 

3.      Loosen the fixing bolt of the focus unit mounting.

 

4.      Remove the entire focus unit by pulling the unit backward.

 

 

 

 

Mount the focus unit

 

5.      Insert the focus unit into the dovetail until the physical limit is reached. Take care on the objective!

 

6.      Tighten the fixing bolt of the focus unit mounting.

 

7.      Connect the cable.

 

 

Watch Video:           Remove focus unit (SCAN)

                                   Mount focus unit (SCAN)