SENSORS
respond to the ambient light level to automatically turn the headlights of a car on or off. An illuminance sensor mounted near the dashboard monitors the brightness outside the car and turns on the parking lights or headlights when the brightness drops below a certain light level. Auto anti-glare rearview mirrors also have an illuminance sensor that automatically adjusts the mirror reflectance when it detects intense light, such as high-beam headlights, from a rear-approaching car at night, so that the driver is not dazzled by the headlight glare.
Also providing comfort, colour sensors help give information on brightness or colour functions for displays, dashboards, and interior lighting, for example, dimming of the head-up display. Interior illumination according to certain situations or moods is one of the big topics for car manufacturers today. Scientific studies show that light influences the mood and the condition of the driver.
Adjustment of brightness or colour can support the driver to remain attentive while driving. Special filters are used to achieve sensitivity close to the human eye. RGB sensors improve the categorisation of the measured light, in order to distinguish the different times of the day, weather conditions, or between natural and artificial light sources. Also, encoder modules can be found in electric power-assisted steering motors, electric brakes, and traction motors, to send accurate speed and direction signals to the car’s control systems.
Optical data transmission With the heavy increase of sensors in today’s vehicles, a large amount of data is sent to the central unit board for processing. Once processed, the data is transferred to the vehicle’s network. This network can be split
Fig 1: A peek at Photo ICs’ variation throughout Hamamatsu’s wide product range.”
into safety networks, so cameras, mm-wave radar, LiDAR, or control networks, like engines and brakes, and information networks, such as car navigation, video, audio. In parallel, the industry is shifting towards electric vehicles with more batteries and electric components inside the motors. This means that modern cars need to communicate even more information in a very fast time and without electromagnetic impacts.
To match the needs of these modern vehicles, the ideal solution is an optical network. This network uses plastic optical fibers composed of photo IC for optical links. Hamamatsu Photonics equips manufacturers with Hamamatsu Fiber Optical Transceivers and there are plans to use optical networks for ADAS*3 networks, including for automatic braking. We are also currently working to develop FOT for optical
networks that are 1 Gbps or even 10 Gbps and faster.
A look at automotive LiDAR One of the most promising developments in recent years has been the use of LiDAR (Light Detection and Ranging) systems, an optical method aimed at measuring distances and speed. It measures distance by emitting laser light to a target and detecting its reflection with the photosensor. It is increasingly important in today’s safety measures as it helps us detect obstacles and avoid collisions. Photo sensors with front-end IC intervene by optically measuring the distance from the car in front and controlling the distance between vehicles. However, these are only one of the many solutions offered by Hamamatsu for TOF (Time-Of-Flight) and FMCW (Frequency- Modulated-Continuous-Wave) LiDAR requirements.
Fig 2: LiDAR for automobiles mainly uses the direct TOF method. This method calculates the distance by calculating the length of time for a light pulse to travel from its light source, be reflected off an object, and return to the sensor.”
Finally, tackling environmental challenges is at the forefront of the automotive industry. Photo ICs for optical links can be useful to help monitor and control the current, voltage, temperature, and functionality of each individual battery cell in order to ensure the best reliability and performance of the battery pack. Additionally, multimedia information including video and audio data that we enjoy in a car is sent via a wire harness or optical fiber cable between various devices such as a display, in-car camera, audio player, and speakers. Light emitter and receiver photo ICs are used for such information exchange through optical links using optical fibers.
www.hamamatsu.com
APRIL 2024 | ELECTRONICS FOR ENGINEERS 37
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54
