Conferences and supporting programme
Power efficiency advantages of TI DLP(R) technology for augmented reality head-up displays
Two major trends in the automotive market are improved ADAS functionality and the transition to electric vehicles (EVs). An augmented reality (AR) head-up display (HUD) is a natural location to display ADAS information to a driver. However, AR HUDs require significantly higher lumens out of the display technology. Texas Instruments DLP® technology enables an efficient, low-power AR HUD solution, which is critical for use in EVs. At the core of DLP technology is the Digital Micromirror Device (DMD), a two-dimensional array of hundreds of thousands of micromirrors that tilt into two states—on and off. Each micromirror reflects red, green, and blue light to display a pixel in the final HUD image. This reflective technology provides a distinct advantage against the incumbent display technology for traditional HUDs, with high efficiency and no dependence on polarized light. With higher optical efficiency, less electrical power is required to produce the lumens required for an AR HUD design. With AR HUDs, it’s more important to create a larger field of view (FOV) than traditional HUDs, in order to augment more of the road scene in the driver’s line of vision. In addition, as safety- critical information is often part of the image content in AR HUDs, a larger eyebox is needed to make it viewable by the driver. Both the FOV and eyebox size specifications drive up the need for more lumens, which can be up to 8 times greater than conventional non-AR HUDs. DLP technology enables higher lumens efficiently which keeps the overall power consumption at a practical level that can be implemented in EVs. This paper will provide a detailed analysis of the power budget and an example system implementation for AR HUD. In addition to the detailed power analysis, this paper will also explore advantages with the driving scheme of the LEDs using pulse width modulated (PWM) display techniques. The DMD is a binary display device, in which the micromirrors are pulse-width modulated in the time domain in order to achieve colors at high bit depth values. This PWM behavior results in a time-sequential pulsing of the red, green, and blue LEDs on the order of 200µs, more than an order of magnitude shorter than traditional display technologies. As the LEDs are self-heating, and higher temperatures decrease the current vs. flux efficiency, these driving schemes allow for unique algorithms to increase optical throughput without increasing total power. This paper will show analysis and measured examples of how this scheme can be implemented. Finally, this paper will show how the maximum power levels for AR can be further reduced and optimized depending on the operating temperature, which leads to an overall lower average power consumption. The efficiency of a DMD system and an intelligent PWM-based drive scheme results in lower total system power that enables practical thermal solutions and opportunities for system cost reduction. This paper will provide detailed analysis, measurements, and implementation details on how this can be achieved in DLP technology- based AR HUD systems.
--- Date: 28.02.2019 Time: 10:40 - 11:00 Location: Conference Counter NCC Ost