Chips That See

An opto-based microchip implemented in standard CMOS technology has made it possible to develop a new type of on-chip functionality which combines normal ASIC technology with optical filters on the chip diode. The chip emulates the human eye and the way it detects light can be used for industrial purposes to create artificial intelligence for functions such as 3D motion control, eye protection and industrial control, to take just a few examples. This artificial eye can now be produced for less than $2 per chip.

We expect that many different industries can benefit from this new chip, industries such as health technology, consumer and automotive. Currently, we can demonstrate different prototype systems for optical mice, color recognition and control of protective welding helmets. The development, which started with a couple of strategic customers in Scandinavia, means that we eagerly anticipate a bright future for intelligent optical measuring systems, more popularly known as ‘artificial eyes.’

Our idea of artificial eyes as motion sensors
Our ideas arise from the more industrial application areas where we use lasers or other light sources to generate photonic energy at a certain band and then measure the reflected photonic energy with an optical eye. This means that you measure the photonic energy at a specific transmitted wavelength, e.g. a laser beam in the 800–900 nm range and then measure the reflections of the photons. This principle can be applied to many different on-chip sensor elements.

In Figure 1 below, we have placed a light source in the same plane as our sensors. With the aid of reflections and a lens patent issued and implemented in cooperation with the Technical University of Denmark Risø Campus and the system house OPDI Technologies, it is possible to measure distance, 3D motion and positions.

This is done by taking a small image section consisting of 4–9 diodes. Then the photonic energy is measured in the individual diode as a function of time. The photonic energy is converted into voltage which is then observed in the diode array. The voltage of the individual diode is then an expression of how much photonic energy there is in the reflected laser light.

In the event of the surface moving, the reflected light energy will move across the individual diode which will then, in conjunction with specially developed software, calculate 3D motion. By detecting this 3D motion, the system can be used as a laser computer mouse or a simple trackpad system for a mobile phone. Similarly, the light system could be used to measure distance based on the same 3D functionality.

Figure 1: Schematic diagram of a laser system used as a computer mouse or trackpad in mobile devices. The laser hits a surface which is reflected irregularly and back to a patented lens system. The laser light continues onto a diode array which collects and calculates the light energy as a function of time. The motion can then be calculated. The system can be used in a long row of optical 3D motion detectors. This can replace the earlier mechanical 3D motion sensors primarily found in consumer electronics such as laser computer mice or trackpad devices in mobile phone that were, implemented according to capacitive or inductive principles.

The chip, which implements the above functionality, has already been certified and integrated in many products which will arrive on the market soon.

Brightness measurements the easy way
Having experienced sunny days, we know that it is great to wear a pair of sunglasses. From a purely practical point of view, what actually happens when we put on sunglasses is that we turn down the energy that the eye detects. Adjusting the light content by putting on sunglasses actually means that we are turning down luminance. In principle, what we really want to do with this chip is to determine the luminance in relation to what the eye detects and then use this detection to control windows, glasses, TV screens, GPS receivers or instrument panels in cars.

In order to decide the energy (luminance) that a human eye sees, we place different filters over the chip in the areas where the diodes are located. We have to use two filters in order to be able to determine the photonic energy in the wavelength ranges that the human eye can perceive. We can choose to place a red filter in front of a diode and measure the energy. This will measure the energy in a normal eye’s field of vision but also in the infrared range.

In the infrared range there is a lot of energy which we normally perceive as heat. Infrared rays are created by the sun and are harmful to the eye in large amounts. To get a more accurate picture of the energy content, these wavelengths need to be filtered out. This is achieved by measuring the energy content through a green filter.

The photonic energy behind a green filter does not contain infrared rays and therefore you can – with great approximation – mathematically add together the energy from these two filters to get a proper idea of what type of luminance can be found in the field the two diodes can see. In other words, we have implemented a luminance sensor which measures the energy that the eye perceives.

Applications that can benefit from brightness control
We can use this to turn the brightness level up or down on TV screens, mobile phones and many other light-sensitive applications in order to save power and batteries. At the same time, we can also create sensors that can be used to protect the eyes. We envisage sunglasses, ski and snow goggles, motorcycle visors, welding helmets, etc.

Get started fast and with low risk
In order to help our customers to get working with optical chips, Delta has developed various conceptual prototypes which our clients can use straightaway. We have prototype opto-chips consisting of diodes, filters, etc.

Acquiring sensor prototypes give you the opportunity to experiment and ‘play’ your way through development and solving tasks. This can be compared to what was previously done with the FPGA solutions before entering into complex SoC designs.

DELTA has now worked with ASICs and optics for more than 20 years. We believe that the future lies in combining optics and ASIC technologies to form new solutions. During this time, we have gathered a vast amount of application knowledge that we would like to share with you to help you innovate. At the same time you can verify the ‘Proof-of-Concept’ before you decide to move on to an actual development project. A complete development project can cost up to DKK 2–3 million and this is why DELTA believes it is important that the concept can be tested before you go ahead with that sort of investment.

The opto-chip can be supplied with or without optical filters according to your needs and desires. At our laboratories in Denmark, we have equipment that can design and add optics directly onto the individual photo diodes. If you would like advice and guidance, we can quickly assemble a team with knowledge of both optics and electronics. You won’t find this combination of technologies anywhere else in Scandinavia.

Figure 2: Prototype has both large and small diodes in different locations on the chip.

Would you like to experiment with our prototypes?