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    Hello. This is Juan Alvarez. And this is part one of a three part series, Wearable Displays with the TI DLP Pico Technology. In part one, we will look at wearable display systems, including AR, Augmented Reality, and VR, Virtual Reality. We will look at optical architectures. And then we will wrap it up with benefits of head-mounted display systems.

    Section two and three will be discussed later in a different webinar. And these are focused on wearable display applications to look at the segments, applications, and then looking at TI DLP Pico technology and how it fits into wearable displays.

    Let's look first at the two types of wearable display systems. One is the Virtual Reality, also called VR. And then the second one is Augmented Reality, called AR. For virtual reality, the end user is faced with a fully computer-generated environment. Pretty much, reality or the real world is away from the person.

    These systems can be biocular or binocular. Biocular, it's pretty much replicating the same image on both eyes. And binocular is having a slightly different image on each eye. From an optics point of view, there are two methods that can be utilized-- magnifying optics or eyepiece optics. We will be looking at those in more detail later on.

    For Augmented Reality, or AR, what you'll have is you have the real world. That means that people can look at the real world. And you have computer-generated images that are combined with the real world and interposed with them.

    This actually has multiple ways that you can interface with the eyes. First one is monocular, which is just one eye; biocular, which is replicating the same image on both eyes; and then finally, binocular, which is having an individual image for each eye to represent more of a three-dimensional type of system.

    And then we have optics. For optics, there are multiple ways of doing this. And we have the eye piece and combiner, and then the eye piece and waveguide. And again, we will be looking at these a bit later on.

    So let's start with VR optics. The first case that you see up there with the gentleman looking at this big screen is called magnifying optics. And what we have here is you have a display, and then the display is amplified. And then the amplification goes to the eye, And that's: how that's formed. Typically, this is your typical smartphone that you put there, and then you have some magnifying optics to look at the image.

    And then we have eyepiece optics. And this is more of a projection based type of optics. And what you see here is the imager being able to project the image directly through the pupil. So the focal point itself is not before the pupil. It's actually through the pupil where you're actually seeing the real image.

    There's an example of this implementation called the Glyph. You can check him out. He's called the Avegant Glyph.

    We're now going to look at augmented reality optics. The first one you see there is called eyepiece and combiner optics. A good example of that is a pilot that is using a head-up display in combat.

    How this one works is you have a projection optics that emits light to a curved combiner as a screen. And then that curved combiner reflects the light towards the eye. And then the effect of that, from the eye point of view, is that you're able to see a virtual image through the combiner that looks like just in front of you.

    The next implementation is called eyepiece and waveguide optics. This is more of a Google Glass type of implementation and is quite popular in the industry nowadays. The waveguide, how it helps, is that you have production optics that feed into the waveguide through some sort of a technique. In some cases, it can be through a slit.

    Then the light travels through a waveguide. The pupil is amplified maybe by 2x, 3x, 4x. And then that pupil, through [? another grid, ?] it goes out into the eye. And then the eye is able to see the image through an eye box.

    And so that's how that one works. There's one implementation that was originally patented by Nokia and is now licensed to Vuzix. And this one is the one that I mentioned that uses the slanted gratings. And then the principle is called Total Internal Reflection, or TIR.

    Now that we have looked at various optical architectures, let's go and look at wearable display system considerations. The slide that you see here is focused on the display itself. And so the first one is image quality.

    So for image quality, if you look at the different aspects of it, the first one is going to be color accuracy, color performance. And that is represented by the crayons there that you see there.

    The second one is going to be feel factor, which is how much gap there is between each pixel. Obviously, the smallest amount of space would create and cause a better image presented to the end user. And specifically for these pictures which is there with the rectangles with the pixels is actually a real [? DLP chip ?] photograph with a very, very small, very good feel factor, very small gap between the pixels.

    And then finally on image quality, it's more of what kind of content are you going to be displaying? So are you going to be looking at videos? Or are you going to be looking at text and symbols? So it all depends on what you do there.

    The second aspect is dynamic contrast ratio, also called NC contrast ratio. And this is critical across VR and AR. But specifically for AR, it's going to be instrumental given that contrast ratio-- the higher the contrast ratio, you're going to get a better image quality as your text and your symbols see through through the real world.

    So for example, on the left, on that image called dynamic contrast ratio on the left, you'll see that that is actually a good example of low contrast ratio where you actually see a box surrounding the image itself. And then on the right, you see an example of high contrast ratio where you virtually don't see any seams around the display itself. It's just the real world, and then the graphics that are presented to you are pretty much seamless.

    The other consideration is resolution. So resolution, this is very self-explanatory. For DLP products or DLP Pico products, we have from [? NHC ?] up to 1080p right now. And it really depends in terms of what you want here in terms of, obviously, the less resolution is going to be more cost-effective. Higher resolution is going to cost more money. So it depends on what you need here for the user.

    I guess the one caution or one thing you have to think about is pixellation. And so what is the minimal resolution that your system requires that still provides a good image quality to the end user?

    Last but not least, you have PICO display panel size. So for this one, what we would like to help you think through is that-- well, there's a couple of aspects here. One is the panel size itself. And so for DLP Pico products, the panel size is measured in inches, and it varies between 0.2 and 0.4 inches.

    And the dependency here is as panel size goes bigger, then you will inherently have a bigger field of view. And also form factor may end up being larger as well given the panel size. So depends here, again-- depends on what you want to achieve. More panel size is going to imply more cost, is going to imply more field of view, which is a positive. But it's also going to imply that you may have a larger form factor as well.

    The second aspects of wearable display systems considerations involves the entire system, meaning the entire end equipment. For the first one, it's called display latency. Think about a situation where you are trying to man a drone remotely through some eyewear.

    The latency here, the display latency, will be the time it takes for the drone to use the camera, communicate that via wireless to the system itself, and then when that image is communicated to the system, then that is being displayed to the end user on a display. Well, all that time that it takes to go from that drone down to the point you're actually watching what the drone is watching is the display latency.

    In this case, for first-person viewer situations, which is one of the categories here, display latency's really critical, to a point where if your drone is going really fast and your drone has just observed a tree, and you don't have time to react because you have not seen it yet, then your drone may end up crashing.

    The second one is power, and this is one that is important as well. And one of the things that we probably don't think about much [? where ?] we should is not just about power on the active mode-- so let's say, for example, maybe we use the wearable display 15, 20, 30 minutes in a day, 1 hour. So the power that needs to be considered here is the overall power that the system is taking between charges. And this is the active time, and then the standby time. And all these should be able to give you a good budget.

    Now, the other thing for wearable displays is battery location. So in many instances, integrators have decided to put the battery elsewhere, not on the head, because it does add weight as well. So in that case, it may give you more flexibility from a power station. The second one is weight itself, as mentioned. You really don't want to have a battery that is so heavy that it is difficult to [? sustain. ?]

    And then finally, in some cases, you may have stations or you may have situations where you may be plugged in all the time. And so think about maybe a situation where somebody's playing a game where they're just looking around. They're just having an experience, but they're really not mobile or [? go ?] into the field. In that case, a [? blocking ?] situation may be acceptable.

    I guess the key point here, for both display latency and power, is that it's all going to depend on what your needs are. But these are things that you should definitely consider and try to budget for.

    Finally, for wearable display systems considerations, we're going to look at specifically about the head and the eyes, which are obviously critical in a system. The first thing on the head, just a quick note, is size and weight. Obviously, whatever you wear on your head needs you to feel comfortable so that it doesn't get you the focus on what you're trying to do.

    And this is going to be a matter of size, how small can you make it. And then in terms of weight, how lightweight it can happen so that it's easy and enjoyable to be able to wear these displays for a long time.

    The second aspect here are your eyes. And obviously, each human eye is going to be different for each one. And there are three wearable here that we want to look at. First is the field of view. And in general, for any human being, we have what we call the extent of visible world. And this is typically over 120 degrees field of view for horizontal.

    Here, it depends how much field of view you want to attain or you want to be able to achieve. You may argue that in some cases, you want to have an immersive experience-- for example, in VR, where you may want to try to get as close as you can to 120 degrees. In some other cases, you may want to have a smaller field of view.

    We've noted that for industrial applications and for augmented reality applications, 45 degree field of view is probably a good number. And if you look back at Google Glass, that end equipment was around 14 degree field of view, just for comparison's sake.

    The second one on the eye is the inter-pupillary distance, which can be biocular or binocular. And this is the distance between your eyes. So from pupil to pupil, what's the distance? And it varies. For males, this is between 52 to 28 millimeters. And then for females, 52 to 76 millimeters.

    The point here is when these end equipments are designed, they have to adjust to different genders-- male or female, a child or an adult. And you'll have to be able to look at what is common, what's average, and how much of the population you want to cover. There's actually a study there in 1988 that was done on a survey that talks about these numbers that you see here.

    The other one is the pupil size. And pupils, human beings are different, and they range from 3 to 9 millimeter. And the mean is around 6.2 millimeter.

    You do have to cover the entire pupil to be able to get a good image through the eye. For this case, if you target something like around 5 to 6 millimeters, you're still going to require a lot of mechanical adjustments to be able to center the pupil exactly where it needs to be. Again, every eye is different. And inter-pupillary distances are going to be different as well.

    And then if you want to plan for a pupil size with minimal adjustments-- and we're talking about a 12 to 15 millimeters-- we have seen that 6, 7 millimeters are perfectly fine with some adjustment. Again here, it depends on the end equipment, depends on the design, and depends on what your needs are.

    Well, that is it for part one, where we covered different system architecture, including optics and types of wearable display systems. And then we also covered system considerations. The next one will be part two, wearable display applications, where you're going to get a good idea of what are the applications, what are the markets, details, and information for each different type and how to differentiate. Please remember to go to training.ti.com, and under Products, select DLP Technology to be able to access part 2.

    In addition to these webinars, you can learn more about DLP Pico technology by visiting us at ti.com/DLP. You can also type DLP2010, DLP3010, or DLP4710 to look at the different products for the product line.

    You can also start a new project or learn more about the technology by typing ti.com/gettingstarted. You can also learn about all the different applications supported by DLP Pico technology at ti.com/picoapplications. And just in general, you can learn more about TI products at ti.com. Thank you, and have a great day.

    This video is part of a series