Components
One field of ASULAB activities is the development of electronic, optoelectronic and microtechnical components. Normally these components are intended to meet the requirements of a specific watch. However, at a later date they may find application not only in the watch sector but also in other areas of microtechnics and microelectronics, since they are designed with a view to minimising their size and power consumption.
The examples described below show that ASULAB is capable of offering specific solutions in very diverse fields of electronic components.
Displays
ASULAB develops electro-optical displays for the specific requirements of the watch industry and other applications with similar requirements. The traditional watch hand displays enable (at least in daylight) a highly legible, low-power display under a wide range of lighting conditions and are very pleasing to the eye. As a general rule, our development work is aimed at reaching similar product characteristics for digital displays as well. The need to achieve good legibility even in direct sunlight forces us to use reflective systems, since the power consumption of emissive systems is unacceptable for watches. These systems are optimised for low operating voltages and currents, wide reading angles and small size (in relation to the display surface) as well as thickness.
The endeavour to achieve more aesthetically pleasing solutions together with the above-mentioned requirements has led to the development of various dichroitic displays (also known as "Guest-Host" displays) as well as to TN (Twisted Nematic) and FMTN (First Minimum TN) systems which enable colour displays.
Compared to segment displays, matrix displays exhibit a significantly higher power consumption. Nevertheless, in order to meet the requirements for watches, we are working on bistable technologies, in particular with displays based on cholesteric liquid crystals.Many of the technologies are also specialised on account of our particular requirements.
Some examples of displays produced at ASULAB
This is why ASULAB carries out the development of the corresponding manufacturing technologies in parallel with the development of the displays. In cases where it proves advantageous, we also carry out the associated construction of special machines.
Special technologies are also necessary in order to meet the mechanical requirements for watch construction. These include the facility to manufacture any desired external shape (not only parallelepipedic) as well as displays with holes for the pointer shafts. The latter characteristic is shown in the picture which exhibits liquid crystal displays for a combined analogue/digital watch.
Quartz resonators
ASULAB has been developing quartz resonators for more than 25 years and was indeed the first company in Europe to develop and produce resonators using photolithographic techniques. As a result, we have acquired many years of experience in the development and manufacture of MEMS (Micro Electro Mechanical Systems) through bulk production methods ("micromachining"). Today, activities are focused on AT-cut resonators working in shearing mode and in the frequency range of 30 to 200 MHz in the fundamental mode. Experience gathered in recent years made it possible to master the mode structure of these resonators, to increase their frequency and drastically reduce their size.
Ageing studies have also shown that these components produced industrially in large quantities have a superior long-term frequency stability.
These resonators are produced and marketed by our sister company MicroCrystal.
Quartz resonator operating in shearing mode at 155 MHz
Micro-reed switches
Magnetostatic sensors are particularly valuable for portable applications because they require little energy or space, are sealed, and can withstand high mechanical stresses. The reed switches currently found on the market are made of two ferromagnetic metal blades placed in a glass tube. ASULAB has developed a technology that allows the manufacture of micro-reed switches by electrodeposition and micro-machining on glass plates. Components manufactured according to this process are 2.00 x 1.40 x 0.75 mm in size. This micro-reed is shock resistant up to 5,000 g (g = acceleration due to gravity), whereas 100 g is sufficient to destroy a conventional reed switch.
Detail view of a micro-reed switch
Development of integrated circuits
The development of CMOS application specific integrated circuits (ASICs) is a major part of ASULAB's activity in electronics. Integrated circuit design is oriented towards low supply voltages and very low power consumption compatible with the requirements of a wristwatch.
From the range of our products we would like to mention a RF front-end circuit for GPS receivers which has been developed using BiCMOS technology. Its consumption is as low as 7mA, at 2V supply voltage. The associated digital integrated circuit, in CMOS 0.5µm technology, includes 1.9 million transistors and performs the correlation operations for the 12 independent channels of a GPS receiver.
We develop the application-specific peripheral blocks for numerous microprocessor ASICs and undertake, if necessary, adaptations to the 8-bit processor core used as a standard block. The consumption of these ASICs is about 1µA at 1.5V in active operating mode.
The applications include the products listed under "Watches" and "Systems".
