Press & News: Case Studies

Hitachi tailors LCD displays for Merloni Elettrodomestici appliances

Introduction
The home appliance market, particularly that of white goods, has been going through a quiet revolution in recent years. This revolution has been driven by developments in technology - particularly digital technology. The cost of micro-controller chips and other electronic components has decreased while the processing power, performance and the range of potential applications for the technology has grown. This has given appliance design engineers the opportunity to re-evaluate the way they think about products in terms of aesthetics, usability and manufacturing.

Merloni Elettrodomestici is no exception – the company has led the trend in Europe towards the adoption of electronic control of home appliances. Five years ago less than 20% of its product range used digital electronics, today over 65% of Merloni’s products use electronics to help run them. This digital revolution has had an influence over all facets of the design, manufacturing and marketing of white goods.

The challenge
Merloni design engineers approached Hitachi Display Products Group when they were in the early stages of development of their new high-end Ariston AVG16 washing machine. As a high specification flagship product, the Ariston AVG16 required an LCD interface that would meet a number of demanding conditions and exacting standards.

First and foremost, the LCD module must to be robust enough for a typical home environment. Kitchens and utility rooms and the operation of a washing machine can create conditions that are hostile to electronic components so robustness is a key consideration. The LCD module had to be designed to withstand a degree of vibration, heat and humidity.

As a flagship product, the aesthetics of the machine was a key consideration for Merloni. The LCD module was to provide the only user interface for the machine, so not only did it need to show a range of detailed graphics and information clearly in all light conditions, it also had to look good as a design feature itself on the facia of the Ariston AVG16.

Merloni’s design engineers spent some time considering the performance and aesthetic requirements of the LCD module and were very clear about the appearance and size of the screen. Hitachi’s challenge was to develop and refine an LCD module that would satisfy this specification. In addition, cost was a critical issue. In order for the LCD module to be a viable component within the Ariston AVG16, Hitachi had to ensure that it could be produced for Merloni at an acceptable unit cost.

Finding the solution
Following the initial discussions with Merloni, Hitachi’s product engineers began developing three possible executions of the LCD module, each of which offered Merloni slightly different performance and screen colours. Merloni’s design engineers had a very clear idea of the screen colour that they wanted, however the only way to get this right was for Hitachi to prepare some working samples of the LCD display to test. This enabled the Merloni design team to assess the aesthetics and performance of each sample before making a decision on which would go into mass production.

“Custom building an LCD module is always a very iterative process. You have to be sure that every aspect of the design is right before you push the button on mass production. With Merloni, we went through four to five product revisions before reaching the final specification that met all the design, production and cost criteria,” comments Mark Dalton, Product Marketing Engineer for Hitachi Display Products Group.

The Ariston AVG16 washing machine is designed so that the LCD screen is the main interface for the user (see picture). Traditional electro-mechanical dials and indicator lights have been replaced by the LCD display that communicates everything that the customer needs to know about the machine and its operation. The LCD module is able to display text and graphics clearly and concisely, including graphics that represent the type of wash cycle selected, a progress bar showing how far through the wash cycle is, as well as water temperature and time.

A tailor-made LCD module
After working through the various product developments in collaboration with Merloni’s design engineers, Hitachi agreed on a specification that met all the criteria. Hitachi’s design group in Taiwan had developed and modified the samples to the point where Merloni was able to make a final decision.

“Hitachi has been very professional in their approach to helping us solve the Ariston AVG16’s LCD display challenge. Their knowledge and input in the development of an appropriate LCD was invaluable. The result is a display solution that meets our very demanding requirements of aesthetics, robustness and cost,” comments Adriano Mencarini, Research & Development Manager for Merloni Elettrodomestici in Fabriano, Italy.

The final product that Hitachi provided was a ¼ VGA LCD module with a 3.8-inch (diagonal) screen constructed using transflective Film STN technology. It boasts a customised blue on white screen colour and is able to operate between –20oC and 70 oC with high resistance to humidity, shock and vibration. The module uses a white LED backlight to improve robustness and operates in a transmissive or reflective mode. Given the operating environment of the LCD module, it was decided that it should have a ‘sleep mode’ that switched the display from a transmissive mode – when the backlight illuminates the screen – to a reflective mode - where the display uses ambient light to show information - when the appliance is not in use.

“A great advantage in using an LCD display as the user interface for an appliance, particularly in Europe, is that it can help reduce manufacturing costs. When manufacturing products for many different European markets, the LCD display can be used to reflect the relevant country and product markings, without the need to badge or print in the local language on the unit itself. Simply load the relevant country specific software and the product is customised for its market,” comments Mark Dalton, Product Marketing Engineer for Hitachi Display Products Group.