Micro-Optics

Reflectors, Diffusers and Micro-Lenses crafted in excellence

Micro-lens arrays and complex Fresnel lenses have become a key element of any compact camera optics, and the evolution of smartphones and tablets is driving the demand for ever more advanced and miniaturized optics. In addition, micro-lenses are used in wave-front sensors, for fiber coupling, or for homogenizing light sources.

Grayscale Lithography is essential for the creation of such state-of-the-art technologies: With it, the molds are generated. Those then are replicated by LIGA to create a metal shim, which in turn is used as a master tool to create replications by molding, imprinting or hot embossing.

Aside from lenses, Grayscale Lithography is utilized to fabricate a multitude of other micro-optical components. Examples are micro prisms, waveguides, blazed gratings or micro-mirrors. In addition, Computer Generated Holograms (CGH) and special security labels are other applications where Grayscale Lithography excels.

Due to the strict requirements in the fabrication of diffraction gratings, standard methods like interference lithography are often not applicable. Direct Write Lithography on the other hand allows fast and precise manufacturing of VLS and standard gratings.

Our DWL series includes a variety of high-performance Grayscale systems: The DWL 66+ represents the ideal Research & Development tool, offering all levels of Grayscale Lithography and a multitude of options. The top-end DWL series (2000 and 4000) comes equipped with air-bearing stage. professional Grayscale package, and high accuracy features as standard.

Requirements

  • Very precise shape control
  • Excellent surface roughness
  • High throughput also for very deep applications
  • No stitching effect
  • High resolution
  • Flexible substrate sizes for different applications
  • Diffraction gratings: Strict requirements for surface quality, groove position, and groove profile

Application images

 

Blazed gratings

A blazed grating is a diffraction grating which is designed to have an optimized efficiency at a particular wavelength and diffraction order. Both the angle of their sawtooth-like profile and the groove spacing is tuned to match the application in question. Blazed gratings are key components in a number of optical instruments, such as monochromators and spectrometers, which in turn are important tools for many fields of science, sensors, and communication systems. - Courtesy of IGI

Textured surfaces and decorative effects

Surface texturing by Grayscale Lithography is used to tailor a surface to exhibit properties like hydrophobicity, friction, haptics, and adhesion. This is of interest for example in touch panels, dirt-repellent coatings, medicine, and many other areas. Our example shows a compound structure – a complex structure made out of micro- and nanostructures. The insect eye, for instance (in particular the moth- or fly-eye), consists of a series of compound structures. - Courtesy of ShenZhen Nahum-Eli Optical Technology Inc.

Diffusers and reflectors

Targeted 3D micro-structuring of a surface leads to controlled reflection or diffusion of light. This type of uniform 2.5D structuring can be accomplished with Grayscale Lithography. Tailored diffusers have applications for example in light sources and illumination, like backlight units in LCD displays. The example shows a retro-reflector structure. - Courtesy of karmic.ch

Microlenses, microlens arrays

Similar to Fresnel lenses and blazed gratings, microlenses and microlens arrays are key components in modern-day micro-optics. They are used in wavefront sensors, for fiber coupling, or for homogenizing light sources. With Grayscale Lithography, the customization of microlens arrays in terms of geometrical density, shape, and radius of curvature is quickly and easily accomplished.

Micro-lenses, micro-lens arrays

This image illustrates a further example for micro-lenses, in this case concave in shape. The example shows lenses written in 15 μm thick AZ4562, with a pitch of 30 μm and a radius of curvature of 16 μm.

Diffractive Optical Elements (DOE)

Multi-level DOEs are valuable devices commonly used for light modulation. By changing the phase profile of a laser beam, DOEs can split and shape the beam in well-defined ways, enabling the efficient generation of beam arrays or complex light patterns. Incredibly precise and sophisticatedly patterned DOEs can be created using Grayscale lithography.

Fresnel lenses

This compact lens design consists of a number of concentric rings. Originally invented to reduce mass and volume of lenses used in lighthouses, it is now a crucial component in today's micro-optics and optoelectronics, for example in miniature cameras such as we find on our mobile phones.

Key benefits

Our Grayscale Lithography systems are the ideal tool for your Micro-Optics applications, due to the following characteristics:

  • Resolution down to 300 nm

  • Stitching reduction functions

  • Substrates from small pieces to G8 panel sizes

  • Shape optimization software

  • High precision stage system

    for accurate pattern placement.

  • Application specific writemode

    to optimize resolution and throughput.

  • High power diode laser

Products

Our specialist Grayscale tools, the DWL 66+ and the DWL series, are the ultimate choice for your Micro-Optics applications, offering Advanced and Professional Grayscale performance levels. In many instances, the Standard Grayscale level of performance, as available in our MLA series, may also be perfectly appropriate for your requirements. Please consult our experts for advice.

Contact

Get in touch with us for more information about our products and services, answers to questions about our technology and everything else about Heidelberg Instruments.

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