Scanning laser beam displays based on a 2D MEMS

Abstract

The combination of laser light sources and MEMS technology enables a range of display systems such as ultra small projectors for mobile devices, head-up displays for vehicles, wearable near-eye displays and projection systems for 3D imaging. Images are created by scanning red, green and blue lasers horizontally and vertically with a single two-dimensional MEMS. Due to the excellent beam quality of laser beams, the optical designs are efficient and compact. In addition, the laser illumination enables saturated display colors that are desirable for augmented reality applications where a virtual image is used. With this technology, the smallest projector engine for high volume manufacturing to date has been developed. This projector module has a height of 7 mm and a volume of 5 cc. The resolution of this projector is WVGA. No additional projection optics is required, resulting in an infinite focus depth. Unlike with micro-display projection displays, an increase in resolution will not lead to an increase in size or a decrease in efficiency. Therefore future projectors can be developed that combine a higher resolution in an even smaller and thinner form factor with increased efficiencies that will lead to lower power consumption.

Accommodation-Free Head Mounted Display with Comfortable 3D Perception and an Enlarged Eye-box

“…A MicroVision MEMS laser projector was selected for the image engine, with dimensions 36x6x53 mm. The laser beam created by the projector is designed to diverge proportionally with the image size [33] specified as 0.03 ∘ with a 0.5 mm minimum beam diameter [34].…”

Development of a parameterization image stitching algorithm for ultrashort throw laser MEMS projectors

“…However, because the laser MEMS projector is a temporal multiplexing device, there is a trade‐off between image resolution and refresh rate. For example, a biaxial MEMS Lissajous scanner operates with resonant frequencies f H and f V . The product of the refresh rate R and the total number of image pixels N cannot exceed the product of the two resonant frequencies: Therefore, for a given MEMS resonant frequency, increasing the image resolution decreases the frame rate and vice versa …”

A Novel Gyroscopic Actuation Concept for 2D MEMS Micromirrors

“…An alternative to this is electromagnetic actuation. This approach whatsoever leads to a high current consumption and the need of one or several permanent magnets on chip or in package [1]. In our approach this dilemma is solved by using a merely resonant actuation in such a way that an indirect quasistatic deflection can be achieved exploiting gyroscopic effects as stated below.…”

“…A large percentage of use cases requires or benefits from a 2D MEMS mirror concept that can be deflected about one resonant "fast" horizontal axis and a "slow" vertical static axis to be able to perform a regular multiline scan as depicted in Figure 1a. 2D MEMS micromirrors of this type were under development in several groups recently [1,6,7]. Designing a MEMS micro mirror to achieve a large static amplitude is challenging.…”

“…MEMS scanning micro mirrors are an emerging technology with possible applications ranging from consumer pico projection [1,2] to 3D scanning [3], automotive HUD [4] as well as medical applications [5]. A large percentage of use cases requires or benefits from a 2D MEMS mirror concept that can be deflected about one resonant "fast" horizontal axis and a "slow" vertical static axis to be able to perform a regular multiline scan as depicted in Figure 1a.…”