PA-Series

Before purchase

Is it possible to measure stress with the PA system?
No. It measures retardation, not stress.

However, the stress can be obtained on the user-side by noticing that the retardation is the result of the stress multiplied by the thickness multiplied by the photo-elastic constant.

The data processing function (software option) has a stress calculation module, for customers who need it.

It is not possible to guarantee calculated values, as the device has no knowledge about the real shape of the device under test, other that thickness information provided by the user.
Is it possible to measure the refractive index profile?
No. The system measures a difference of refractive indices (i.e., birefringence ordinary index and extraordinary index), by looking at the change of polarization, not the absolute value of the refractive index.
Is it possible to measure semi-transparent materials?
It depends on the level of transparency. Please check the system by evaluating a known sample. Measurements may differ due to the transparency. Please thoroughly understand the system before trusting measurements.
How much is the resolution?
The field of vision range is changed by the height of measurement head unit as it moves up and down.

Thus, the resolution is determined by the height of measurement head unit, as the number of data points is constant, i.e., equal to 2464 pixels in the horizontal direction for PA. The resolution is obtained by dividing the field of vision range by the number of data points.
In the measurement environment, is a darkroom required?
It is not necessary but is recommended as reflections of indoor light could affect measurements.
Is it possible to use in a cleanroom?
Yes. Please contact Photonic Lattice for detailed information.
Is it possible to combine with automatic stages to perform automatic measurement flow?
Yes. PA/WPA system can be controlled by an external program using our remote-control function (software option), that can be purchased if needed.
Is it possible to customize the PA system?
Yes. Please contact Photonic Lattice to discuss.
How can a material be checked for birefringence?
Sandwich the material between two polarizing films, and then turn one film relative to the other.

If brightness or color tone change by turning, the material has birefringence.
Is it possible to measure retardation directed towards the vertical axis?
No, it is not possible.
Is it possible to measure the dependence of retardation on the angle of incidence?
No, it is not possible.
Is it possible to measure frosted glass?
It depends on the level of transparency. Please check the system by evaluating a known sample. Measurements may differ due to the transparency. Please thoroughly understand the system before trusting measurements.
Is it possible to measure red-colored materials?
No. It cannot be measured because of the measurement wavelength. Green light is not transmitted enough through red-colored materials.
Is it possible to change the objective lens freely?
No. The system should be calibrated for each objective lens at Photonic Lattice. Please do not attempt to modify by yourself.
Is it possible to use other light sources by removing measurement head unit?
Our suggestion is to use the PA-MT type.
The measurement head unit is removable, but please contact us before attempting to remove the measurement head by yourself.
Is it possible to use the PA system in some public facility?
Please contact us.

After purchase

How can I set the baseline?
Firstly, place the device under test on the stage to confirm the field of vision range and the focus. After focusing, remove the object from the stage and then press the “Baseline” button.
What is the time interval before resetting to baseline?
It is desirable to reset to the baseline just before each single measurement, if possible.

It is possible that atmospheric temperature changes over time can affect the baseline data.
Can the PA system be used to measure high values of retardation?
The PA system provides reliable measurement for retardation up to 130 nm. Beyond 130 nm, we recommend the WPA system. This situation is shown in the chart below:

PA system

The PA system will record the correct value up to 130 nm of retardation, but beyond this point it will record values as shown in red on the above chart. The WPA system will follow the blue dotted line and is therefore recommended when large values of retardation need to be measured.
What is “measurement accuracy”?
The main contributor of noise with the PA system is random noise associated with the CCD sensor.

It can be reduced by increasing acquisition time.

The amount of data to be acquired changes when the “measurement accuracy” condition changes in the software.

The measurement time therefore becomes longer as a larger amount of data is acquired in higher accuracy modes.
What is recommended when changing objective lens?
The system is calibrated for each objective lens delivered with the equipment. Thus, lens condition must be updated into the software by the user each time the lens is replaced.
The field of vision range is changed by a height change. The baseline should be reset because polarization condition will not be the same, resulting in measurement error.
The field of vision range is changed by a height change. The baseline should be reset because polarization condition will not be the same, resulting in measurement error.
Is it possible to measure just after starting?
Yes, however it is desirable to wait for approximately 30 minutes after starting to allow for stabilization of the system.

Principle of measurement

Under what conditions does birefringence occur?
It occurs under the following conditions:
1.Anisotropic molecular orientation in the material
2.Internal stress is present inside the material
3.Birefringence occurs in general as the result of a combination of the two.
How can retardation measurement results be used?
Results can be used for quality control and optimization of manufacturing processes, for example, an injection molding process.

Results can furthermore be used for stress evaluation and process control of glass products.
What kind of influence does birefringence have on products?
If the birefringence becomes large, the phenomena below may occur:

①It may decrease the image formation quality of a lens, as birefringence perturbs optical paths.

②It can cause uneven coloring on a rectangular product, used for example in an optical display, when observed diagonally, resulting in unwanted visual artifacts.

③It can be a sign of unwanted residual stress in glass products, resulting in unwanted fragility or local defects.

④It can cause unstable conditions in injection molded products, resulting in unwanted evolution of shape with time.

WPA-Series

Before purchase

Is it possible to measure stress with the WPA system?
No. It measures retardation, not stress.

However, the stress can be obtained on the user-side by noticing that the retardation is the result of the stress multiplied by the thickness multiplied by the photo-elastic constant.

The data processing function (software option) has a stress calculation module, for customers who need it.

It is not possible to guarantee calculated values, as the device has no knowledge about the real shape of the device under test, other that thickness information provided by the user.
Is it possible to measure the refractive index profile?
No. The system measures a difference of refractive indices (i.e., birefringence ordinary index and extraordinary index), by looking at the change of polarization, not the absolute value of the refractive index.
Is it possible to measure semi-transparent materials?
It depends on the level of transparency. Please check the system by evaluating a known sample. Measurements may differ due to the transparency. Please thoroughly understand the system before trusting measurements.
How much is the resolution?
The field of vision range is changed by the height of measurement head unit as it moves up and down.

Thus, the resolution is determined by the height of measurement head unit, as the number of data points is constant, i.e., equal to 2464 pixels in the horizontal direction for PA. The resolution is obtained by dividing the field of vision range by the number of data points.
In the measurement environment, is a darkroom required?
It is not necessary but is recommended as reflections of indoor light could affect measurements.
Is it possible to use in a cleanroom?
Yes. Please contact Photonic Lattice for detailed information.
Is it possible to combine with automatic stages to perform automatic measurement flow?
Yes. PA/WPA system can be controlled by an external program using our remote-control function (software option), that can be purchased if needed.
Is it possible to customize the WPA system?
Yes. Please contact Photonic Lattice to discuss.
How can a material be checked for birefringence?
Sandwich the material between two polarizing films, and then turn one film relative to the other.

If brightness or color tone change by turning, the material has birefringence.
Is it possible to measure retardation directed towards the vertical axis?
No, it is not possible.
Is it possible to measure the dependence of retardation on the angle of incidence?
No, it is not possible.
Why can WPA measure large retardation?
WPA can measure large retardation because it uses a different type of sensor (phase plate type instead of polarizer type) and it uses 3 wavelengths to overcome the single wavelength limitation (with only one wavelength, we cannot determine how many “laps” is included in the phase shift).

As a result, WPA can measure retardation as large as 5 or 6 times the wavelength.
The actual upper limit depends on the material.
すりガラスは測れますか?
Is it possible to measure frosted glass?

It depends on the level of transparency. Please check the system by evaluating a known sample. Measurements may differ due to the transparency. Please thoroughly understand the system before trusting measurements.
Is it possible to measure red-colored materials?
No. It cannot be measured because of the measurement wavelength. Green light is not transmitted enough through red-colored materials.
Is it possible to change the objective lens freely?
No. The system should be calibrated for each objective lens at Photonic Lattice. Please do not attempt to modify by yourself.
Is it possible to use other light sources by removing measurement head unit?
Our suggestion is to use the WPA-MT type.
The measurement head unit is removable, but please contact us before attempting to remove the measurement head by yourself.
Is it possible to use the PA system in some public facility?
Please contact us.

After purchase

How can I set the baseline?
Firstly, place the device under test on the stage to confirm the field of vision range and the focus. After focusing, remove the object from the stage and then press the “Baseline” button.
What is the time interval before resetting to baseline?
It is desirable to reset to the baseline just before each single measurement, if possible.
It is possible that atmospheric temperature changes over time can affect the baseline data.
What is “measurement accuracy”?
The main contributor of noise with the PA system is random noise associated with the CCD sensor.

It can be reduced by increasing acquisition time.
The amount of data to be acquired changes when the “measurement accuracy” condition changes in the software.
e therefore becomes longer as a larger amount of data is acquired in higher accuracy modes.
What is recommended when changing objective lens?
The system is calibrated for each objective lens delivered with the equipment. Thus, lens condition must be updated into the software by the user each time the lens is replaced.
Is it possible to change the height of the measurement head after setting the baseline?
The field of vision range is changed by a height change. The baseline should be reset because polarization condition will not be the same, resulting in measurement error.
Is it possible to measure just after starting?
Yes, however it is desirable to wait for approximately 30 minutes after starting to allow for stabilization of the system.

Principle of measurement

Under what conditions does birefringence occur?
It occurs under the following conditions:
Anisotropic molecular orientation in the material
Internal stress is present inside the material
Birefringence occurs in general as the result of a combination of the two.
How can retardation measurement results be used?
Results can be used for quality control and optimization of manufacturing processes, for example, an injection molding process.

Results can furthermore be used for stress evaluation and process control of glass products.
What kind of influence does birefringence have on products?
If the birefringence becomes large, the phenomena below may occur:

1.It may decrease the image formation quality of a lens, as birefringence perturbs optical paths.

2.It can cause uneven coloring on a rectangular product, used for example in an optical display, when observed diagonally, resulting in unwanted visual artifacts.

3.It can be a sign of unwanted residual stress in glass products, resulting in unwanted fragility or local defects.

4.It can cause unstable conditions in injection molded products, resulting in unwanted evolution of shape with time.

ME-Series

Before purchase

Is it possible to measure the thickness of a multilayer film?
Yes. However, only two parameters can be measured at once, and only if the thickness and refractive index of all other layers are known.
Is it possible to measure the film thickness on a transparent substrate?
The ME-210-T system can measure thin film if the substrate is thicker than 0.5mm.
What is the spatial resolving power?
In high-definition mode, it is possible to obtain data intervals down to 5.5 μm.

However, please consider the resolving power of the optical system to be around 20 μm.
Is it possible to change the measurement wavelength?
Modifying the measurement wavelength requires customization and will be considered on a case-by-case basis. Please inquire with customer support.
Can the measurement equipment be used in a cleanroom?
Yes. Please inquire with customer support.
Is it possible to use the equipment as a spectroscopic ellipsometer?
No. It can be used only as a single wavelength ellipsometer.
Is it possible to combine with a loader device?
Yes, it is a matter of customization. Please contact customer support.
What is the measurement speed?
The maximum speed is 20,000 points per minute in standard mode, and more in high-definition mode.
What is the maximum possible measurement area?
Standard model: up to 8 inches.
Upgraded model: up to 12 inches.

SE-Series

Before purchase

Is it possible to measure the thickness of a multilayer film?
Yes. However, only two parameters can be measured at once, and only if the thickness and refractive index of all other layers are known.
Is it possible to measure the film thickness on a transparent substrate?
No.
Is it possible to change the measurement wavelength?
Modifying the measurement wavelength requires customization and will be considered on a case-by-case basis. Please inquire with customer support.
Is it possible to buy a measurement head alone?
Full equipment must be purchased first. It is used as a calibration set when purchasing additional measurement heads.
Do you provide software development kit (SDK)?
Yes. We sell it as an option.