Abstract: Laser projection is a bit of a historical technique. As its name implies, it uses the laser as the light source and uses the MEMS glass structure to reflect the imaging technology on the surface of the object. Its advantage lies in its ability to make the projection structure very small and can even be placed on smartphones. Medium, and even non-flat surfaces, can focus on imaging
Laser projection is a bit of a historical technique. As its name suggests, laser light is used as a light source and MEMS glass structures are used to reflect the surface of an object. The advantage of this technology is that it can make the projection structure very small, even in smart phones. And even non-flat surfaces can focus on imaging, without additional focus mechanism on the lens. However, in the past, due to excessive application and cost restrictions, it was rarely seen in the market.
Because it was difficult to put it into the general consumer market in the early days, companies that had invested in laser projection technology in the early days, such as MicroVision, turned to military equipment as the touchstone for laser projection. They designed a head-mounted battlefield information display device for the U.S. military. Basic functions were Just like today's AR display devices, through Substrate Guided Relay (SGR) optics, that is, a transparent lens with special optical characteristics, Microvision applies its own PicoP technology to pump images and maps it. Photos, real-time videos, and other images are reflected in the eyes of the wearer as a useful tool for communicating battlefield situations and strategies.
Figure | Battlefield Information Visual Feedback Diagram
Figure | US Army Battlefield AR Vision Feedback System
In the Wave Gulf War that began in the 1990s, MicroVision received considerable income from the provision of a large number of US AR battlefield display devices. However, after the war ended, MicroVision also began to actively lay out the general consumer market and send it to the military due to a sharp drop in demand. The use of black technology for civilian use.
Figure | Laser projection machine structure for the three-color laser projected image through the MEMS light machine, with the advantages of sharp picture quality
For MicroVision, the actual application scope of the existing pico projector technology is still too narrow. If it can only be used for home or office briefing, the future development space is limited. Therefore, like MicroVision, it turns to the miniaturized projection module as its core and expects it to be embedded in various corners of life.
At present, the main application level of laser projection includes vehicle display, home intelligent terminal display, commercial display, and mobile display.
Chart | Future Prospects of Laser Projection and IR 3D Sensing Technology
In the car display technology, it will focus on the window projection, which includes two kinds of directions, one is the broadcast of advertising images, the audience is the passerby and other drivers outside the car, the other is the driving itself, that is, the traditional The replacement of the head-up display, with the help of a display module embedded in the car, places the car information in the window glass as a method for navigation or real-time monitoring of traffic information. In the automotive display, it may be more emphasis on the aftermarket. Because the laser module itself is still more difficult to introduce products that meet the stringent demand for vehicle regulations, it will take a while to improve into the pre-installation market, but the market has already Began to circulate applications, for example, many markets in China have begun to launch automotive window projections.
Figure | Window projection using laser projection technology
In terms of home smart terminal display, considering that smart speakers are generally only able to broadcast information through voice, if the information content is very long, then the voice time will be long, for example, to understand the structure of the weather in the coming days, Then products with display capabilities are more intuitive. In addition, if you shop through a smart speaker, you will not be able to see the actual appearance of the product, and it may happen that something you bought doesn't meet expectations.
Figure | Although a bit contrary to the original intention, but more and more smart speakers built-in screen, but the shape is also limited by the screen
In addition, there have been many smart speaker programs or have already made display screens into products, but such products are limited by the size of the display screen and the appearance cannot have a bolder design. If a laser miniature projection module is used, not only is it projected The screen can be resized as needed, or it can be placed on various flat or non-flat surfaces such as a home wall or a white cabinet, and it can have a pretty good projection quality without focusing.
In addition, in the area of commercial embedded projection, such as store merchandise display, product interactive pages can be directly projected onto glass windows with polarized films, and even IR sensors can be used to interact in real time or directly to shop.
Figure | Interactive Projected Showcase Window
In terms of mobile display, MicroVision and Lenovo and Sony have cooperated and developed a lot of products in the past. Lenovo did not go public because of market strategy adjustments. However, Sony's laser micro projectors are not only cheaper and lighter in size, but also have better resolution and lower price than competitors in the market. Sony, however, purchases related technology patents from MicroVision using a structured authorization method. And use it to design your own products.
Figure | Lenovo had planned to launch a Smart Cast projection mobile phone based on laser projection and IR sensor technology, but unfortunately due to Lenovo's poor operating conditions
In the Gulf War, the U.S. military used a large number of personal display devices based on laser projection as the communication of battlefield information and the communication of commands. At that time, it was possible to achieve color display in limited hardware size limits. The military network can display virtual information images superimposed with real-world scenes. The commander can grasp the distribution of resources and combat power on the battlefield in real time, and translate the commands into visual concepts to be synchronized to the views of all soldiers who use the equipment. Perform battlefield management, and with GPS positioning and map display, even in the case of very poor visibility, it is possible to synchronize the position of the enemy and the Jun army in real time, and even mark the enemy's location.
The concept of overlaying virtual information with real-life scenes is quite consistent with the AR technology we use today. However, AR equipment will not be commercially available until 2018. Military AR equipment based on laser projection was back in the 90s. The US military is widely used.
Finally, in the ascendant AR and VR technologies, laser projection can also help the entire system become thinner and lighter, and bring better display effects. Of course, apart from traditional AR and VR mechanism design, Microvision will also develop direct in the future. The technique of projecting an image onto the retina. At this time, there may be people who think that AMOLED has a burning screen problem. Will the laser that directly projects on the retina burn the retina? But in fact, there is no need to worry too much. The intensity of light that is projected to the eyes will be adjusted to the range that the human body can bear. Otherwise, it is impossible to pass the examination and approval, but also to have a good display effect in view of safety. This is a dilemma for such technology, but This is not impossible. More stringent technological developments and verifications are still needed.
Invest in embedded projection and imaging technology for AR and VR equipment
The Microvision PicoP core combines laser projection and scanning technology. With the combination of a laser emitter and a MEMS light engine, coupled with IR emission and sensing capabilities, it can focus on any object surface and even achieve 3D Sensing at the same time. , Detection and real-time establishment of three-dimensional object surface.
Figure | Laser projector from Japan Explay Japan, also taking the miniaturization design direction
In addition to Microvision, Explay Japan also has a similar laser projector solution, which is also focused on miniaturization. However, Microvision has already pioneered laser projection in mobile phones and combines infrared scanning capabilities. Explay Japan does not have a similar product.
Laser projection is actually a laser as a light source, a display technology with the characteristics of MEMS opto-mechanical structure, and LCD, DLP parallel projection of the three major technologies, the latter two light sources using traditional light bulbs, the newer models also use LED light source, Because of the different structure of the light machine, the technical threshold of laser projection is obviously much higher, and because of the limitation of the laser power, the brightness is difficult to effectively improve. Therefore, the laser projection has gradually developed toward the miniaturized projection technology, while the LCD and DLP have become larger. screen display.
In terms of technical principles, highly focused laser projection technology using a laser characteristic, a light source and then with MEMS deflection scanning process to convert the point light sources to scan the laser line, while the advanced processing of the picture plane, the concept of a bit Like the cathode ray tube display (CRT display) in the early days, only the cathode ray tube projected an electron beam, and the laser projector was a laser.
Microvision uses laser sources for all three primary colors, but competitors also use semiconductor lasers as the light source only for red and green light. Blue-light semiconductor lasers use LED light sources instead of blue lasers to achieve size and cost due to high cost. Balanced, but this solution will still be larger than the pure laser solution.
Figure | MicroVision's PicoP micro-projection technology with permanent focus, wide viewing angle, and bright colors
However, because of the high complexity of the laser projection structure, the cost is difficult to reduce effectively. In addition, due to limitations of the micro-projection technology due to equipment battery, processing performance, etc., the market is very small, so the market size of laser projection cannot be compared with other projection technologies. Because DLP's opto-mechanical structure can also be miniaturized, miniaturized projectors in recent years have dominated the market with LED-based DLP technology.
Enters Vehicle and Security Lidar Technology with 3D Sensing Technology
As mentioned earlier, in addition to laser projection, its laser-based and infrared-based 3D Sensing technology is currently one of the core technologies of MicroVision. With its projection technology, remote object detection, motion detection, and even gestures can be performed. Interact with projected content and more. This 3D Sensing technology can also be used as an indispensable LiDAR product for autopilot. Because of MicroVision's technological advantages, its mechanism size can be much smaller than that of competitors on the market, facilitating the integration of more LiDAR products into the entire vehicle, or Without changing the size of LiDAR and changing the original body design, MicroVision's LiDAR technology can clearly identify the shape and stereoscopic features of the scanned object. Other similar products cannot achieve similar results.
Traditional LiDAR uses a laser as the source of emission, and then determines the actual distance of the target object based on the time interval of reception-reflection. Then, according to the distance and the angle of laser emission, the position information of the object can be derived through a simple geometrical change. Due to the small influence of laser propagation on the outside, LiDAR can detect distances up to 100m. Compared with traditional radars using radio waves, LiDAR uses laser radiation. The wavelength of laser rays used by commercial LiDAR is generally between 600 nm and 1000 nm, which is far below the wavelength used by traditional radars. Therefore, LiDAR can achieve higher accuracy in measuring object distance and surface shape, which can generally reach centimeters.
Figure | Traditional LiDAR technology, based on laser projection, sensing distance, but the size of the body needs to have a certain space to accommodate, it is difficult to further miniaturization
MicroVision's LiDAR products actually belong to mid-range products in terms of sensing distance, and they are still in the R&D phase. Although many customers are interested, it still takes some time to polish before entering the market. However, with the miniaturized structure and low-cost design, different thinking can be brought to the sense design of the automotive market.
Figure | Microvision's Lidar design is similar in size to its laser projector, currently limited to vehicle gauge laser modules are still in development, and it is not yet available in the market, and the sensing distance is short
Laser projection technology has high potential, embedded design can expand the breadth of applications
Although Lidar for cars is still in the design and verification stage, LiDAR products for security should soon be available in the market. Because the characteristics of MicroVision LiDAR are like the scanning lines of traditional cathode ray tubes, it can scan the surface of objects at high speed and return the three-dimensional features of objects. In other words, if it is within close enough distance, say a few meters, it can be done. To the effect similar to FaceID, to use the three-dimensional features of the facial features to identify who is coming, the accuracy can be better than the traditional camera-only technique.
Figure | Security LiDAR Technology Schematic
Because MicroVision's LiDAR is extremely small, it can easily be stuffed into small robots, including storage robots, sweeping robots, etc., and map generation technology of related systems can be complemented with LiDAR's own high-precision detection capabilities. Man-Machine products will also use LiDAR technology as a dodge barrier and achieve the ability to fly accurately in limited space.
MicroVision has been verified by many products for small-size image projection capabilities. It has also been confirmed by related customers. Although there is room for improvement in terms of related costs and reliability of some applications, it is driven by market demand. Related technologies are also evolving. It is believed that in the future, display devices based on laser projection will be more diversified and applications will become more popular.
Laser projection lost its advantage in the first wave of consumer projection market, and it relied on the advantages of technology to generate light and heat in the military market. However, after its miniaturization and cost improvement, it was immediately followed by more massive consumer projection and sensing. In the market ecosystem such as industry, laser projection technology should be able to get a place.
