Analysis of Product Architectures of Pin Array Technologies for Tactile Displays

Refreshable tactile displays based on pin array technologies have a significant impact on the education of children with visual impairments, but they are prohibitively expensive. To better understand their design and the reason for the high cost, we created a database and analyzed the product architectures of 67 unique pin array technologies from literature and patents. We qualitatively coded their functional elements and analyzed the physical parts that execute the functions. Our findings highlight that pin array surfaces aim to achieve three key functions, i.e., raise and lower pins, lock pins, and create a large array. We also contribute a concise morphological chart that organises the various mechanisms for these three functions. Based on this, we discuss the reasons for the high cost and complexity of these surface haptic technologies and infer why larger displays and more affordable devices are not available. Our findings can be used to design new mechanisms for more affordable and scalable pin array display systems

Designing a New Tactile Display Technology and its Disability Interactions

People with visual impairments have a strong desire for a refreshable tactile interface that can provide immediate access to full page of Braille and tactile graphics. Regrettably, existing devices come at a considerable expense and remain out of reach for many. The exorbitant costs associated with current tactile displays stem from their intricate design and the multitude of components needed for their construction. This underscores the pressing need for technological innovation that can enhance tactile displays, making them more accessible and available to individuals with visual impairments. This research thesis delves into the development of a novel tactile display technology known as Tacilia. This technology's necessity and prerequisites are informed by in-depth qualitative engagements with students who have visual impairments, alongside a systematic analysis of the prevailing architectures underpinning existing tactile display technologies. The evolution of Tacilia unfolds through iterative processes encompassing conceptualisation, prototyping, and evaluation. With Tacilia, three distinct products and interactive experiences are explored, empowering individuals to manually draw tactile graphics, generate digitally designed media through printing, and display these creations on a dynamic pin array display. This innovation underscores Tacilia's capability to streamline the creation of refreshable tactile displays, rendering them more fitting, usable, and economically viable for people with visual impairments

Quantitative Tactile Examination Using Shape Memory Alloy Actuators for the Early Detection of Diabetic Neuropathy

Diabetic neuropathy (DPN) is asymptomatic in its early phases but can cause serious complications as it progresses. Most DPN tests are cumbersome and produce only qualitative assessments, and simpler approaches that yield quantitative results are needed. Techniques that allow patients to perform examinations themselves would be especially valuable. In this study, we focused on quantifying the decline in tactile sensation associated with DPN and developed a measurement device that used a thin shape memory alloy (SMA) wire as the actuator. An ON/OFF pulse current caused the wire to shrink and expand. This vibration was amplified by a round-headed pin, allowing even DPN patients with reduced tactile sensitivity to detect the stimuli generated when lightly touching the pin with their fingertips. The tactile stimuli were ranked into 30 levels of intensity. A key advantage of the device is that it can be used by patients themselves, returning quantified results within minutes. Although developed for DPN, the method can be applied to the detection of peripheral neuropathy in general

Micro Motion Amplifiers for Compact Out-of-Plane Actuation

Small-scale, out-of-plane actuators can enable tactile interfaces; however, achieving sufficient actuator force and displacement can require larger actuators. In this work, 2-mm2 out-of-plane microactuators were created, and were demonstrated to output up to 6.3 µm of displacement and 16 mN of blocking force at 170 V. The actuators converted in-plane force and displacement from a piezoelectric extensional actuator into out-of-plane force and displacement using robust, microelectromechanical systems (MEMS)-enabled, half-scissor amplifiers. The microscissors employed two layers of lithographically patterned SU-8 epoxy microstructures, laminated with a thin film of structural polyimide and adhesive to form compact flexural hinges that enabled the actuators’ small area. The self-aligned manufacture minimized assembly error and fabrication complexity. The scissor design dominated the actuators’ performance, and the effects of varying scissor angle, flexure thickness, and adhesive type were characterized to optimize the actuators' output. Reducing the microscissor angle yielded the highest actuator performance, as it maximized the amplification of the half-scissor's displacement and minimized scissor deformation under externally applied loads. The actuators' simultaneously large displacements and blocking forces for their size were quantified by a high displacement-blocking force product per unit area of up to 50 mN·µm/mm². For a linear force–displacement relationship, this corresponds to a work done per unit area of 25 mN·µm/mm². Keywords: microactuators; tactile actuators; piezoelectric actuators; scissor mechanism; motion amplifier; out-of-plane actuato

FingerTac - A Wearable Tactile Thimble for Mobile Haptic Augmented Reality Applications

ingerTac is a novel concept for a wearable augmented haptic thimble. It makes use of the limited spatial discrimination capabilities of vibrotactile stimuli at the skin and generates tactile feedback perceived at the bottom center of a fingertip by applying simultaneous vibrations at both sides of the finger. Since the bottom of the finger is thus kept free of obstruction, the device is well promising for augmented haptic applications, where real world interactions need to be enriched or amalgamated with virtual tactile feedback. To minimize its lateral dimension, the vibration actuators are placed on top of the device, and mechanical links transmit the vibrations to the skin. Two evaluation studies with N=10 participants investigate (i) the loss of vibration intensity through these mechanical links, and (ii) the effect of lateral displacement between stimulus and induced vibration. The results of both studies support the introduced concept of the FingerTac

Advanced Knowledge Application in Practice

The integration and interdependency of the world economy leads towards the creation of a global market that offers more opportunities, but is also more complex and competitive than ever before. Therefore widespread research activity is necessary if one is to remain successful on the market. This book is the result of research and development activities from a number of researchers worldwide, covering concrete fields of research