Display Color Properties

Displays of all kinds are the main channels for human interaction with various devices. Whether it is a mobile phone, tablet, PC, cars, home appliances, info screens, or machine controllers, displaying information and content on display is the most natural way to interact with people. As the variety and usage of displays increase, the color optics of display performance grows in importance. Can the user see the content clearly from various angles? Are the colors vivid and natural at the same time? Are there unevenness or visible defects on display? Do the colors of two in-device displays match when it comes to dual-screen devices?

Humans are gifted with five senses namely sight, hear, touch, taste and smell. These senses help us perceive the world and get the best of the experiences. Technology has certainly adapted to give us best experience by the means of touch. From phone to a watch, from car to fridge, from ATMs to POS, everything is embedded with a touch capacity for human interaction. Delivering such interactive technology comes with a requirement of quality assurance to keep the product consistent and enhance the customer experience. Having shipped a poor quality of touch panels in any device has a significant impact on the quality of device. This certainly affects the device brand and the future of the product. Having a thorough testing cycle in R&D as well in manufacturing line, improves the quality of production, which helps getting better business yield.

Consumer VR headsets have been available since 2015, when a large number of companies announced their own versions of the products. By 2016, more than 230 companies were working on their own VR HMD projects. Most of these projects have since ended and companies have gone bankrupt, but some keep releasing new products, both stand-alone and tethered versions, on an almost annual basis. Oculus (Facebook) released new Quest and Rift devices in 2019, while HTC came up with a new VIVE and Valve announced their Index glasses. Then there is Varjo, a company that keeps amazing their fans with human-eye resolution products, as well as numerous new Chinese companies that are also catching up fast in product design and performance. In CES 2020, there were dozens of new players and products coming to both the VR and AR markets. ^{[1] [2]}

The testing process during R&D of a new smart device involves many aspects. In this blog I will showcase some of the most important areas where we are the best in the world.

When it comes to the development of physical mass products, we work with most of the top-rated companies in the world. Why? Our competence in testing and our ability to help the customer in the early stages of new product innovation makes us unique. The competence of our metrology teams, especially our optical and imaging-related knowledge, combined with extensive knowledge of high-precision robotics, is unique in the world. An example of our competence in component testing is described in the blog Characterizing Diffractive Waveguides. Add an exceptional team and the ability to help customers to solve their problems and that is what OptoFidelity stands for.

We work with our customers as well as further down the line during manufacturing and after sales. For further information please have a look at further details at the Production Testing blog posting or, for tailored solutions, at the OptoFidelity Competencies site.

Production is the key process in bringing the end user products into the market. For our customers, this involves production technology validation, traveling to the factories, meeting tight line ramp-up deadlines and ensuring that production costs are within the business case for the product. In a later phase, the focus moves into production line efficiency improvements and maintaining the systems. Equipment vendor capabilities and level of experience has significant influence on the level of required effort. This blog is outlining our experience for how to create successful projects, a checklist for the key ingredients.

Saying "Well planned is half done" makes perfect sense in measurement automation. In fact, the key for successful projects is to understand production automation targets, measurement, interfaces and delivery logistics. When setting up the project, this understanding provides a solid starting point for the project.

In general, production automation aims at generating value as improved compliance, cost level, quality of results, yield and overall efficiency:

• Compliance: the key target of production measurement and calibration is to ensure that the manufactured units meet the product specifications, i.e. the product quality.
• Cost level: automation provides tools for improving the line throughput and reducing the labor costs. Typically performance metrics are units per hour (UPH), resource level and CAPEX costs.
• Quality of results: automation provides both enhanced accuracy and repeatability when compared to a manual or a semi-automated process, measured by Gage Repeatability & Reproducibility (GRR) metrics or similar.
• Yield: test automation provides the data for the yield improvement (percentage of non-defective items of all produced items).
• Overall efficiency is a combination of the above mentioned items, measured typically with Statistical Process Control (SPC) for continuous monitoring and development.

Successful projects have typically well-defined targets for the automation. The production automation targets provide priorities which have a big impact on the technological choices used in the station design. This target setting also enables possibly needed priority discussion already at the concept design phase to find the correct balance e.g., between UPH, measurement accuracy and cost. Having these discussions and setting achievable targets is important - no surprises should occur in the later phase of the project.

Measurement definition provides the purpose for the test system. This is typically defined in the form of a test list. A test list is created to establish understanding about the relevant phenomenon to be measured, the necessary measurement data for the test result (e.g., to define pass/fail thresholds) and a necessary level of test configurability. The test list is examined hand-in-hand with the production automation targets and performance targets such as the measurement accuracy, resolution and repeatability requirements. Measurement definition makes it possible to create a system concept:

• To find and select the best-suited measurement method and sequence, the key operating principle for the measurement.
• To screen and select the measurement instruments (e.g., camera, optics, illumination, and other sensors)
• To define the actuators providing the required performance (e.g., motion accuracy)
• To develop mechatronics 3D illustration about the system (including moving axis, measurement sequence)
• To create concept description including functions of sub-modules and their interaction as a complete system

Interfaces define how the test system is operated and what the sequence of actions in each interface is – for a production line station the interfaces include:

• Operator interface – how the operator interacts with the system, including system safety
• Physical interfaces – including cabinet size and shape as well as electrical, pneumatics and data interfaces
• Material handling - the way to move and physically interact with the device under test (DUT)
• DUT communication - identify and interact with the DUT software or firmware
• Measurement instruments and actuators – the equipment for control, actuation, sensing and data acquisition
• Data analysis – analyzing the raw data to produce the measurement results
• Reporting – providing the measurement results for the host system, e.g., factory data management or manufacturing execution system (MES)
• Configuration – toolset for setting up the system, making calibrations and configuring the test list, pass/fail criteria and system parameters
• Test sequence – the procedure to carry out the measurement sequence using all the interfaces

Well-defined and designed interfaces enable validation of system parts and the system as a whole. Having a well-thought-out sequence of actions is important for system reliability. Parallelism enables improved UPH e.g., by completing the analysis of previous DUT in parallel with measuring the next DUT. System level design is an area where the experience is very valuable; this enables performance, innovative designs, maintenance and use of proven technology platforms.

The purpose of delivery logistics is to create the demand-supply network for the station which is suited for the needs of factory locations and processes. Work at the factories is typically split into three phases: pre-production, line ramp-up and sustaining-mode production. Defining the delivery logistics to meet the demands in each phase is important – making it possible to meet the schedules and produce good quality prototypes and products. Delivery logistics involves:

• Station manufacturing – parts lead times and availability, incoming quality check (IQC), assembly quality control, burn-in, testing and outgoing quality check (OQC), packing
• Shipping – lead time for shipping and customs, delivery term used, cost level of tariffs, factory incoming shipments procedures
• Pre-production builds – arrangements for tools, resourcing and access rights, on-site work for installing, setting up and calibrating the stations, developing the best fit test sequence and pass/fail thresholds, validating the station accuracy and repeatability
• Production ramp-up – similar to pre-production but without development, focus on GRR for the stations to ensure station to station variations are within limits
• Sustaining production – OSS including on-site and off-site support, station performance monitoring and improvements, spare parts, repairs, maintenance and periodical calibrations

Work at the factory is fast-paced. This is the point where everything comes together – including the product hardware and software and the stations in the production line. Experience in the delivery logistics helps quite a bit in preparing, making things run smoothly and dealing with unexpected changes.

OptoFidelity can deliver turnkey production measurement and calibration systems – this statement is backed by 100+ different purpose-built systems that OptoFidelity has developed for volume production. Our systems are designed to fulfill the customer-specific measurement needs and used by world-leading manufacturers of smartphones, tablet computers, AR/VR devices, laptops, vehicle infotainment systems and industrial smart machinery.

Based on several years of experience, OptoFidelity has developed standard products and technology platforms to efficiently combine software, robotics, camera technologies and sensors to create demanding test systems. This gives a head start for the projects as the OptoFidelity platform frequently provides a large part of the needed overall implementation.

We at OptoFidelity are always trying to find ways to improve our working methods to support our customers’ needs – we have built our expertise and capabilities since 2005. Currently, OptoFidelity provides operations and service support for an installed base of 5,000+ pieces of measurement equipment in China, Vietnam, Taiwan and the USA. Our philosophy is to work close to our customers in both R&D and production, and we have design teams in the USA, Finland and China who are easy to work with. OptoFidelity provides delivery logistics with test equipment manufacturing in China and Europe. As a team, we have special expertise in mechatronics, optical metrology, signal processing and software as well as system design for production equipment. Together with special application expertise for measuring smartphone sensors, AR/VR technology, displays and touch UI, we can provide unique value for our customers.

We at OptoFidelity are enthusiastic about the accuracy of our test and measurement systems. In order to pursue the highest possible accuracy and repeatability, we have integrated several technologies into the TOUCH test system, such as purpose-built mechanics, linear motors, multi-axis synchronized motion, machine vision based positioning, robot calibration methods, and camera calibrations.

Smart devices are electronic devices which integrate various sensors and actuators which enable product features. Smart devices are generally connected to other devices or networks and can operate to some extent interactively and autonomously. Development of a smart device starts from component and technology selection and continues with product R&D, manufacturing and after sales. End user experience is the key differentiator for any smart device product. It is built from well performing components and skillfully integrated product hardware and software.

Each year we seek enthusiastic, bold and open-minded Trainees to join our troops. This summer was no different and we were excited to have overall six new OptoFidelitians. We promised that these Trainees will have a summer with cool robots, awesome colleagues and unique projects – how well did we succeed with this promise? Let’s find out from the authors themselves: Sini, Joonas, Olli-Pekka, Ismo and Juho!

Sini and Joonas, you worked as Software Trainees, what did you get to do here?

Sini: During the summer I got to do a lot of work directly related to my education and interests. This was the most important thing for me, since as someone mostly focused on users, UX and UI design back-end coding is not inspiring to me. I was surprised how much people here were eager to hear my opinions and how much those really affected the outcome of the projects.

I designed and made prototypes of a few user interfaces and got to develop one from start to finish. In the university I hadn’t learned a lot about UI programming and the experience from here is patching up important holes in my know-how.

What really made the summer enjoyable here was my project team. The average age of the team was probably somewhere in the mid to late twenties, which helped us connect and have fun too on the side of work. I look forward to continuing as a part-timer when I start my studies again!

Diffractive waveguide gratings are one of the most promising display technologies for head-mounted augmented reality (AR) devices. Verifying the quality of these gratings requires extremely accurate optical measurements, a key expertise at OptoFidelity.

We at OptoFidelity are happy to introduce a new image quality testing solution for AR/VR head mounted devices – OptoFidelity™ GoldenEye HMD IQ!

Industrial XR will be the breakthrough area, Finnish leaders say. A lot has happened in the AR&VR ecosystem in the last few months. Industry leaders from Finland’s AR&VR ecosystem had a virtual roundtable discussion, and the key comments were collected for this article. The Finland AR&VR ecosystem includes leading global companies such as www.varjo.com, www.dispelix.com, www.optofidelity.com, www.leonidasoy.com, www.futuremark.com, www.immersal.com, and much more. An additional AR technology highlight is, that Microsoft has Hololens development activities in Finland. Finland is a true global focal point in AR&VR development.

OptoFidelity CTO Kimmo Jokinen, Kari Peltola, the Chairman of VR Finland and CEO of Leonidas, CMO Jussi Mäkinen from Varjo, CEO Jufo Peltomaa from Immersal and industry pioneer Steven LaValle from the University of Oulu all share a common view, namely that industrial XR solutions will make a breakthrough during 2019.

Is it safe to buy a refurbished smartphone? This is one of the most common questions written to Google when a consumer is considering buying a used smartphone. “Are they any good?” “Will they function well?” “Can I trust that it works?” The answer is a resounding “Yes,” if you ask OptoFidelity. “Based on our experience from the reverse logistics of smartphones, the quality of second-hand phones for sale is excellent, especially if you buy them from established suppliers in the business,” Hans Kuosmanen, SVP from OptoFidelity, confirms.

OptoFidelity is a well-known automated testing solution provider for smartphone manufacturers, providing various smartphone test solutions for more than ten years. Likewise, OptoFidelity is as experienced in the reverse logistics of smartphones, partnering with leading companies in the business, such as FutureDial. OptoFidelity™ Fusion has already been in operational use in reverse logistics of smartphones for two years. The test solution automatically recognises over 100 different smartphone models from most of the globally known brands.

Maturity of AR/VR/MR devices is improving significantly during 2019. In order to offer seamless UX for consumers, more comprehensive testing methods are needed. A novel content tracking method for AR/VR/MR testing purposes is introduced by OptoFidelity, the leading test solution provider for HMD UX testing.

In 2019, we can expect a wealth of exciting virtual and augmented reality devices arriving: for example, Oculus is going to release the standalone Quest headset, and Nreal raised $15M of funding to produce a sunglass-sized AR headset. In CES 2019, there were almost a hundred exhibitors in the AR/VR Gaming category.

Quick development of the new technology gives rise to the need to verify performance in product development as a part of continuous integration. This post focuses on measuring head tracking accuracy, which is comprised of many measurable elements: drifting, jitter, motion-to-photon latency, cross-axis coupling… you name it!

Kick-start for HMD UX testing was done in 2017, when OptoFidelity´s first offering BUDDY-1, previously known as VR Multimeter was launched. BUDDY-1 is a solution for benchmarking the motion-to-photon latency with one degree of freedom. Our BUDDY testers are equipped with a smart camera which captures and analyzes the frames displayed on the headset. BUDDY-1 tracks the optical flow of a target pattern placed in the virtual world and compares that to the physical rotation angle over time, yielding motion-to-photon time. BUDDY-1 is a good work horse for basic motion-to-photon latency measurement e.g. to catch some fatal performance regressions.

OptoFidelity worked in co-operation with University of Jyväskylä, Department of Physics. Our co-operation was related to academic research in the area of HMD testing technology. Our interest was to find new optical measurement technologies and methods for VR headset tracking performance. As an end result, we developed a novel technology for testing HMD´s. If tracking performance of HMD is poor, it will effect drastically to end user experience. OptoFidelity has been working with user interface testing for years. As HMD´s are getting more and more popular, we believe better testing technology is needed as well.

One of the most popular topics in today’s smart device industry and research is the development of virtual and augmented reality (VR/AR) headsets. State-of-the-art, room-scale implementations utilize multiple cameras and sensors to find the position and orientation of the user’s head in the surrounding space. This is called six degrees-of-freedom (6DoF) tracking. Simultaneous Localization and Mapping (SLAM) algorithms, familiar from robotics, are also utilized to make the headset better adapt to its surroundings by recognizing walls and other obstacles. Qualcomm, for example, has implemented SLAM in its new mobile processor [1].

The quality and accuracy of the head tracking are key contributors to the virtual reality experience. Bad performance of the tracking may cause nausea or simply undermine the credibility and immersivity of the virtual reality experience. For the development of the devices and the content, an objective way of assessing the behavior of tracking is necessary. The high quality of the tracking may be quantified by observing e.g., the latency between the user’s motion and the respective update of the display content (motion-to-photon latency), jitter (random shaking of the content) or drifting.

There are several possible ways of testing the tracking performance. Given access to suitable APIs of a headset, one may record and investigate data from the headset’s tracking system, graphics stack or some other components. Another example is application-to-photon latency measurement, where the graphical content is changed. The respective change of the display is observed by an external sensor (such as a color sensor or a camera), and latency between the two events is measured.

OptoFidelity™ GoldenEye Display Test Solution and sample data

OptoFidelity GoldenEye is an automated display test system that is scalable and capable of producing reliable and consistent display quality data. It is capable of testing MURA / MURA detection, uniformity but as well particles within display stack and display surface dust detection. The OptoFidelity™ GoldenEyE software is used with different camera and hardware setups and integrated to RD and factory testing environments. You can read more details about the solution from OptoFidelity™ GoldenEye solution page.

Sample data in the end of this article: includes MURA detection, luminancy uniformity and dust detection samples

Refurbished smartphone testing is not possible with traditional testing approach. Novel technology and thinking is needed in order to overcome the challenges. Especially you can see the problem, when you are trying to automate Android functional testing for refurbished phones.

There are 2.3B Android smartphones in use globally (*). And more and more smartphones are getting a second life as well. This means reselling the phone to another user when the primary user wants to get an upgrade. This reverse logistics business requires testing as well. If you want to sell it with a good price, the phone must work well.

We have been delivering smartphone testing solutions for years. It has been part of our company offering from day one. The testing of smartphones includes quite a lot. In this blog I will showcase some of the most important areas where we are the best in the world.

First of all, I believe it might be good to split the value chain of the smartphone business a little bit. In our company we are defining four major segments in the smartphone business: 1) Component validation, 2) Product development, 3) Manufacturing and 4) After-sales.

OptoFidelity was nominated by Photonics Finland as the Photonics Company of The Year. We are very pleased and proud of this nomination. We took the opportunity seriously and had a little celebration at our office the other day. While having a glass of sparkling wine with our team, we also discussed some recent experiences with photonics and its relation to testing. We have been investing in the photonics industry for years. And a few truly interesting cases were brought up by the team. ”How do testing and photonics, and specifically test robotics and photonics, fit together?” you might ask.  

OptoFidelity’s US offices had some exceptional visitors the other day. Check out their video to see what happened!

– do you know what your customers thinks about your QoS?

I was invited as a speaker to the OLED (organic light emitting diode) technologies summit in Berlin, November 23-24. This was the first time that I had the opportunity to attend this type of venue, with top scientists discussing the very niche area of OLED technology. What I heard and discussed there was truly eye-opening.

“Values are personal and reflect the vibe around the company”

I had the opportunity to be an invited speaker at the SID Display Week symposium in Los Angeles. Display Week is one of the largest venues of the display industry, gathering more than 400 speakers/authors and 6,000+ professional visitors together for a whole week.

Creating a new product concept from scratch is like a thrilling voyage. It’s  at least a combination of a vision of the destination, good itinerary, guts and good luck. And the final result, alive and kicking product, can be as rewarding as the dream journey. When developing and launching one of our latest products, OptoFidelity^TM Fusion, I really thought it was like winning the Amazing Race. And that’s a lot to say – for a Finn.

Virtual reality (VR) allows a person to interact with a three-dimensional image or environment through the use of display, optical and sensor technology, in connection with powerful graphics and CPU. Wall Street has high expectations for the market potential of VR; much depends, however, on the results in the sales report. I would like to discuss the reasons behind the figures of the User Performance (UX) of VR HMD. However, this is not a formal study but rather a light recollection of personal experience, observations and interviews.

”UI is a fork. UX is feeling full.” – Whitney Hess

After I have been chewing over the SLUSH experience for couple of days, I can align that the leading start-up event in Europe was an overall positive experience for a first-timer. The event is not only about matchmaking for start-ups and financiers, but it has become “the event” for high tech companies in particular, where you can find first-rate presentations, discussion and networking opportunities all in one. Maybe it’s because the event is intended for start-ups, but the entire SLUSH population is open and ready to listen to what others have to offer. Everyone is a potential partner for your business, one way or another. This open willingness to communicate makes the event stand out among ordinary trade fairs.

The ongoing evolution of smart devices means endless, and sometimes also sleepless, R&D hours for our test automation developers. We have to have a good radar to sense what will be the new trends and features on phones or any multimedia device – and we have to head our expertise and solutions to meet the expectations. Most preferably we have to do that before customer can define what this means from testing aspect.

”As a company, we don’t define ourselves by our output, but by the challenges we solve”