Along with extensive research on the three-dimensional (3D) printing of polymers and metals, 3D printing of ceramics is now the latest trend to come under the spotlight. The ability to fabricate ceramic components of arbitrarily complex shapes has been extremely challenging without 3D printing. This review focuses on the latest advances in the 3D printing of ceramics and presents the historical origins and evolution of each related technique. The main technical aspects, including feedstock properties, process control, post-treatments and energy source–material interactions, are also discussed. The technical challenges and advice about how to address these are presented. Comparisons are made between the techniques to facilitate the selection of the best ones in practical use. In addition, representative applications of the 3D printing of various types of ceramics are surveyed. Future directions are pointed out on the advancement on materials and forming mechanism for the fabrication of high-performance ceramic components.

3D printing of ceramics: A review

High-speed 3D shape measurement with structured light methods: A review

A lithographic apparatus configured to project a patterned beam of radiation onto a target portion of a substrate is disclosed. The apparatus includes a first radiation dose detector and a second radiation dose detector, each detector comprising a secondary electron emission surface configured to receive a radiation flux and to emit secondary electrons due to the receipt of the radiation flux, the first radiation dose detector located upstream with respect to the second radiation dose detector viewed with respect to a direction of radiation transmission, and a meter, connected to each detector, to detect a current or voltage resulting from the secondary electron emission from the respective electron emission surface.

Lithographic apparatus, and device manufacturing method

We introduce a phase-control holographic technique to characterize scattering media with the purpose of focusing light through it. The system generates computer-generated holograms implemented via a deformable mirror device (DMD) based on micro-electro-mechanical technology. The DMD can be updated at high data rates, enabling high speed wavefront measurements using the transmission matrix method. The transmission matrix of a scattering material determines the hologram required for focusing through the scatterer. We demonstrate this technique measuring a transmission matrix with 256 input modes and a single output mode in 33.8 ms and creating a focus with a signal to background ratio of 160. We also demonstrate focusing through a temporally dynamic, strongly scattering sample with short speckle decorrelation times.

High-speed scattering medium characterization with application to focusing light through turbid media.

A display system for providing a two dimensional image includes an essentially one dimensional light valve array. The diffractive light valve array includes modulator elements which diffract or reflect light incident thereon to an extent determined by an image element to be represented. The display system is arranged such diffracted light from the light-valve array passes through a magnifying lens and is separated from the reflected light from the array. A magnified virtual image of the array formed by the diffracted light is viewed through the magnifying lens. A scanning arrangement between the viewer and the magnifying lens scans the image of the light-valve array across the field of view of the viewer sufficiently quickly that the viewer perceives the scanned image as a two-dimensional image. In another arrangement a printer is formed by scanning a real image of the diffractive light valve array over a printing or recording medium.

Display device incorporating one-dimensional grating light-valve array

For the past six years, Digital Light Processing technology from Texas Instruments has made significant inroads in the projection display market. With products enabling the world’s smallest data and video projectors, HDTVs, and digital cinema, DLP technology is extremely powerful and flexible. At the heart of these display solutions is Texas Instruments Digital Micromirror Device (DMD), a semiconductor-based “light switch” array of thousands of individually addressable, tiltable, mirror-pixels. With success of the DMD as a spatial light modulator for projector applications, dozens of new applications are now being enabled by general-use DMD products that are recently available to developers. The same light switching speed and “on-off” (contrast) ratio that have resulted in superior projector performance, along with the capability of operation outside the visible spectrum, make the DMD very attractive for many applications, including volumetric display, holographic data storage, lithography, scientific instrumentation, and medical imaging. This paper presents an overview of past and future DMD performance in the context of new DMD applications, cites several examples of emerging products, and describes the DMD components and tools now available to developers.

https://eti.pg.edu.pl/documents/176568/264302/emerging_dmd_applications.pdf

Emerging digital micromirror device (DMD) applications

A thermal imaging system (10) contains a focal plane array (14) including a plurality of thermal sensors (50) mounted on a substrate (52). The focal plane array (14) generates both a reference signal which represents the temperature of the substrate (52) and a biased signal corresponding to the total radiance emitted by a scene (11). Electronics (16) process the reference signal and the biased signal to obtain an unbiased signal representing radiance differences emitted by objects in the scene (11). A thermoelectric cooler/heater (38) may be provided to optimally adjust the temperature of the substrate (52) to improve overall image quality. Each thermal sensor (50) contains an electrode (66 and 68) that electrically couples the thermal sensor (50) to the substrate (52) and also allows the thermal sensor (50) to deflect, contact, and thermally shunt with the substrate (52).

Thermal imaging system with integrated thermal chopper

Methods of controlling the illumination source ( 18 ) of an SLM-based display system ( 10 ). It is assumed that the system ( 10 ) displays pixel data formatted into a bit-plane format so that all bits of the same bit-weight can be displayed simultaneously. To provide greyscale, the amplitude of the source ( 18 ) may be modulated so that bit-planes having greater bit-weights are displayed with more intense illumination than bit-planes having smaller bit-weights (FIGS. 2 and 3 ). To avoid visual artifacts, the duty cycle of the bit-plane display times may be shortened relative to the frame period. (FIG. 4 A). The latter method can be accompanied by a shortening of the duty time of the illumination on SLM ( 15 ). (FIG. 4 B). The short duty cycle method may be used together with illumination amplitude modulation, or it may be used with the PWM method of providing greyscale.

Modulated-amplitude illumination for spatial light modulator

A visible light and near infrared imaging device is disclosed. The imaging device comprises X-Y addressing means, an array of opto-electronic semiconductor elements or cells, a multiplexer, a precharge switch, and an amplifier. The X-Y addressing means selectively addresses each cell of the array of opto-electronic semiconductor cells and corresponding multiplexer switch for connecting a reference voltage to each cell to charge each element to the reference voltage, then to isolate each element and vary its voltage in proportion to the intensity of the impinging light, and finally to read out selectively the voltage of each element to the amplifier for amplifying the electrical signals representative of the light intensity to a working level for processing into video signals.

Visible light and near infrared imaging device

A circuit and method of detecting infrared radiations with a focal plane array circuit member comprising storing a charge in a storage device indicative of the intensity of received infrared radiations, periodically transferring the stored charge and then resetting the storage device, storing the transferred charge, providing an output terminal and providing a low pass filter coupled between the output terminal and the storage means.

Dana Dudley

Papers

Emerging digital micromirror device (DMD) applications

Thermal imaging system with integrated thermal chopper

Modulated-amplitude illumination for spatial light modulator

Visible light and near infrared imaging device

Infrared focal plane array processor with integration and low pass filter per pixel