Spectral Slits

We offer two types of entrance and exit slits for spectral devices: manual and motor driven. Both types of slits can be used in the automated spectral devices, but manual slits are applicable only for the manual controlled spectral instruments.

The width of slit is continuously adjustable from 0 to 2.0 mm; the slit height varies from  0 to 10 mm with a special  diaphragm.

All  spectral slits have standard mounting flanges that allows mounting all our optical accessories directly on the slits.



Motor driven spectral slits


Technical specifications

  • width                                   variable from 0 to 2.0 mm
  • parallelism                           ±1 µm
  • accuracy                             ± 10 µm (with 1 mm width)
  • reproducibility                      ± 1 µm
  • reading accuracy                 2 µm
  • single step                          0.5 µm
  • height                                 10 µm


Width of the motor driven slits is continuously adjustable from  0 to 2.0 mm. The slit width control can be performed with a micrometric screw which is rotated  by a stepping motor or  manually. Therefore, the motor driven spectral slits provide a many-sided control. These slits control can be done either automatically or manually.

The embedded controller of the spectral device implements the slit stepper motor control via PC commands. There is a position sensor in the slit mechanism, which is used to determine the initial (closed) state of the slit blades. To connect a motor driven spectral slit to the embedded controller, a cable is available, which  is con-nected to the appropriate connector on the body of the spectral device.

Also, the slit width control of motor driven slits can be performed manually with a micrometric screw which is placed on on the top of the slit housing. The same types of micrometric screws are used in  manual and in motor driven slits,  so the motor driven slit contro in manual mode is the same as for the manual slit – see below.

Due to the fact that the width control of a motor driven slit  is made by many-side manner (either automatically or manually), it is necessary to consider the following features:

  • A stepper motor rotates the micrometric screw in the automatic mode, and the slit width can also be tested  by sight on the control knob of the  screw.
  • When adjusting the slit width using a stepper motor, the drum of the micrometer screw is rotated. A small force applied to the drum during rotation (for example, accidental hand touch) will interrupt the step-per motor operation. Damage of slit is not going to happen, but the real value of the slit width will be different from the value requested in software. In such case, the slit should be closed fully using the control program, and then the desired value of width can be set again.
  • Any manual control of the motor driven slits can be  possible only after stopping the slit stepper motor. At the manual operation mode,  the slit width is determined visually according to measuring indicator of the mi-crometer screw. To continue the motor driven operation after a manual one, you need to coordinate the true value of the slit width with the value of width specified in the software. To do this, the slit should be programmatically closed and then the desired width should be set again.
  • To avoid damaging the slit mechanism  in any automated slit by manual control, you can not set a slit width  less than 0 and more than 2.0 mm .
















Fig.1. Motor driven spectral slits. Drawing.




Fig.2. Connection circuit

Manual spectral slits



  • width                                  variable from 0 to 2.0 mm
  • parallelism                          ±1 µm
  • accuracy                            ± 10 µm (with 1 mm width)
  • reproducibility                     ± 1.5 µm
  • reading accuracy                2 µm
  • height                                10 mm

The slit width is driven with a micrometric screw manually.

Width adjustment of manual slits

Width of a slit is slowly adjusted from 0 to 2.0 mm with use of a micrometric screw on the housing. Graduating mark of the micrometric screw is 0,002 mm (2 μм). Each full revolution  of the knob corresponds to the  opening width of a slit blades of 0,1 mm (100 μм). To increase the slit width, is is necessary to rotate the knob clockwise. To decrease the width, the direction should be  counterclockwise. To install a new value of the slit width with  the maximum accuracy, the value of width should be set by rotat-ing the screw clockwise (incrising width).

Therefore, in case you need to set the value of the slit width  less than its current value, you must first close it to the value less than desired (of about 50 microns ,it is half a turn of the micrometer screw) , and then rotate the drum clockwise to set the desired slit width (see figure below).

The fully closed state of a slit blades corresponds to the position “0” on the knob of micrometric screw.

To avoid damage of the slit mechanism, you can not set the slit width  less than 0 and more than 2.0 mm.



Fig.3. Manual spectral slit. Drawing.



Fig.4. Width adjustment of manul slits