Transflective Digital Holographic Microscope for Simultaneous Thickness and Contour Measurement
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Solution Overview
Problem
Existing digital holographic microscopes cannot simultaneously obtain transmission and reflection information, leading to inaccurate test results, especially when measuring special samples like micro-optical devices.
Innovation Solution
A transflective digital holographic microscope system is designed with both reflection-type and transmission-type light paths, utilizing a Michelson interferometer structure and a dichroic mirror to separate dual wavelengths, allowing for simultaneous measurement of thickness and surface contour information.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single transmission structure or a single reflection structure is used, then the device complexity is reduced, but the measurement precision deteriorates because transmission information and reflection information cannot be obtained simultaneously
Solution Approach 1:
The patent combines transmission-type and reflection-type digital holographic microscope light paths into a single integrated system. The transmission light path includes a transmission objective lens for measuring thickness information, while the reflection light path includes a reflection objective lens for measuring surface contour information. Both paths share common components such as the laser source, polarizing beam splitting cube, and detection system, allowing simultaneous acquisition of transmission and reflection information without requiring completely separate devices.
Solution Approach 2:
The patent creates a multi-functional microscope system that can perform both transmission holography and reflection holography measurements using a unified platform. The system uses wavelength division multiplexing with dichroic mirrors to separate different wavelength bands, enabling the same physical device to serve multiple measurement functions simultaneously - measuring both thickness and surface contour of samples like micro-optical devices.
2Measurement precision
If dual wavelength light beams are used to achieve simultaneous transmission and reflection measurement, then the measurement precision is improved, but the device complexity increases due to the need for wavelength division and separate light paths
Solution Approach 1:
The patent introduces a dichroic mirror as an intermediary component to manage the dual wavelength light beams. The dichroic mirror is designed to reflect the first wavelength (for transmission measurement) and transmit the second wavelength (for reflection measurement). This intermediary element enables clean wavelength separation without requiring complex mechanical switching or multiple beam splitters, simplifying the overall system architecture while maintaining measurement precision.
Solution Approach 2:
The patent resolves the complexity of dual wavelength management by adding a spectral dimension to the light path separation. Instead of using spatial separation alone (which would require complex mirrors and beam steering), the system exploits the wavelength dimension by using dichroic mirrors with specific spectral characteristics. This allows simultaneous presence of both wavelengths in the same spatial path while maintaining separate measurement channels through spectral filtering.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables more complete and accurate three-dimensional structure information of samples by obtaining transmission and reflection information simultaneously, expanding the range of tested samples and allowing for real-time measurement.
Implementation Method 1
a first light beam is changed in polarization direction after passing through a first polarizer, and is divided into two light waves with vertical polarization states after passing through a polarizing light beam-splitting cube
Implementation Method 2
The first reference light beam is reflected by a dichroic mirror, and the second reference light beam is transmitted by the dichroic mirror
Implementation Method 3
the first reference light beam is reflected by the dichroic mirror after adjustment of the polarization direction to a horizontal polarization state by a half-wave plate
Implementation Method 4
then focused by a second lens, transmitted by the first non-polarizing light beam-splitting cube and collimated by the third lens
Implementation Method 5
and interferes with the first object light beam; interference information is received by the first camera
Data Source
AI summary
A transflective digital holographic microscope system belongs to the technical field of microscopes, includes a reflection-type digital holographic microscope light path and a transmission-type digital holographic microscope light path, wherein the reflection-type digital holographic microscope light path is as follows: a first light beam is changed in polarization direction through a first polarizer, and is divided into two light waves with vertical polarization states; wherein the transmission-type digital holographic microscope light path is as follows: a second light beam is changed in polarization direction through a second polarizer, and is divided into two light waves with vertical polarization states, so that the thickness information and surface contour information of the sample can be tested at the same time.