Additive manufacturing of polymer parts via photpolymerization has emerged as versatile production technology. Toolless fabrication of arbitrarily shaped 3D printed parts has shown promise for industrial application, especially when processing high viscosity resins which lead to polymers with enhanced thermomechanical properties. However, until recently these production machines were limited by both field of view and light sources capable of providing sufficient energy density. With the advent of scrolling DLP projectors, high throughput systems could be conceived. By precise signal control and image plane matching, a novel additive manufacturing platform was developed. A pixel pitch of 50 µm is maintained over a printbed of up to 1 m x 0.28 m. It is capable of processing high viscosity resins at a throughput rate increased by over a magnitude compared to conventional Hot Lithography printers, enabling industrial scale production of high performance polymer parts.

Tomographic printing is a 3D printing technique that enables fast, supportless fabrication wherein light is projected through a rotating vial containing a photocurable resin. Usually, vial is placed in an index-matching bath to eliminate refraction at the vial surface. In this talk we will describe our approach to build an easy-to-use tomographic printing system that eliminates the index-matching bath. We use a computational ray-tracing approach to pre-distort projection images to exactly counteract the distortion from refraction at the air/vial interface and projector non-telecentricity. We will show simulation and print examples and expand on recent improvements in our system.

We configured a coded aperture-based real-time super-resolution imaging system using digital micromirror device (DMD). We encoded an object with 128 random patterns using a DMD that can spatially modulate at high speed. ADMM (Alternating Direction Method of Multiplier) was used as an algorithm to solve the inverse problem with a small number of iterations and low computational cost. It took 0.52 seconds to acquire the low-resolution coded images and 0.07 seconds to reconstruct a super-resolution image from them. As a result, we confirmed 1.7 fps imaging capable of acquiring 16x super-resolved 128x128 pixel images in the horizontal and vertical directions.

Please joint us in commemorating the life and work of Roland Höfling.

Gradient descent is an efficient algorithm to optimize differentiable functions with continuous variables, yet it is not suitable for computer generated holography (CGH) with binary light modulators. To address this, we replaced binary pixel values with continuous variables that are binarized with a thresholding operation, and we introduced gradients of the sigmoid function as surrogate gradients to ensure the differentiability of the binarization step. We implemented this method both to directly optimize binary holograms, and to train deep learning-based CGH models. Simulations and experimental results show that our method achieves greater speed, and higher accuracy and contrast than existing algorithms.

In this presentation we show a field of view super-resolution ability while using shifts in time to deal with the diffraction limit as well as the limited density of sampling in space caused due to the stringent size of camera’s pixels/pitch (geometric resolution limit). Using a low-resolution camera, we were able to achieve a high-resolution image by complying with certain conditions that we defined. For that end, we utilized a setup of sub-pixel shifts and grating shifts by time multiplexing, in addition to field of view multiplexing that overcame the diffraction related resolution reduction. The generation of the sub-pixel shifts needed for the operability of the proposed super resolving concept is achieved using DLP device. Improving optical systems resolution is extremely valuable mission in various fields of science and engineering. It helps researchers and industrial companies alike to leap forward the efficiency and ability of their microscopes, telescopes, imaging satellites and aerial photography.

Structured light has become topical of late, allowing custom optical fields to be tailored in all degrees of freedom, and finding applications that include optical trapping and tweezing, microscopy, communications and even quantum protocols. Commonly, the light is tailored in its spatial degrees of freedom for arbitrary polarization, amplitude and phase control, executed on spatial light modulators. This invited talk will outline the role of digital micro-mirror devices (DMDs) in the creation, control and detection of structured light fields, covering fundamentals for “getting started” to the state-of-the-art in real-time control with high speed and fidelity. The talk will cover topics ranging from lasers to single photons, highlighting the versatility of the DMD toolkit.

Polymer powder bed additive manufacturing is the most prolific industrial additive manufacturing technology, thanks to Laser Sintering and High Speed Sintering (HSS) technologies. Recent advancements have included adding additional laser systems (with significant costs) and the use of HSS technologies to increase machine throughput. However, polymer powder bed AM technologies are still very limited on processable materials and quality control. Ascend Manufacturing is leveraging high power digital micromirror devices (DMD) to overcome these obstacles and provide a commercial next-generation additive manufacturing solution. This presentation will introduce Ascend Manufacturing's novel Large Area Projection Sintering technology and discuss the additional advantages of area-based processing.