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Hello. Thank you for joining the Texas Instruments new product update webinar. Just a reminder that this is a weekly series every Thursday at 10:00 AM Central. A few quick announcements before we get started.

This webinar will be recorded and available online at ti.com/npu. All phone lines will be muted, so if you have questions, please use the chat box, and we will try to answer in real time, or you can contact your TI salesperson or field application engineer. Today's topic is ultrasonic lens cleaning for self-cleaning cameras. I will now pass it over to Avi Yashar for introductions.

Thank you so much. My name is Avi Yashar. I'm a product marketing engineer for our low power audio team. I'm very excited here today to talk about ultrasonic lens cleaning for self-cleaning cameras and sensors. It's a really new cool technology. I also have my colleague Kelly Griffin in this Webex. So if you have any questions, please feel free to chat him, and he'll do his best to answer those.

So without further ado, we'll get started. In today's webinar, we're going to talk about what is ultrasonic lens cleaning, what does a typical ULC system look like. And then we'll provide some resources to get started. And once again, Kelly is in the Webex, so please feel free to ask any questions you have through the chat at any time.

So just getting started, ultrasonic lens cleaning is a technology that uses piezo transducers to resonate glass or other materials to clear the contaminants on the surface. So these piezos can come in different form factors, ring transducers, cylindrical transducers, even piezo strips. And depending on the geometry and material of the lens that you're trying to clear, whether it's a circular, or it's maybe a silicon material for thermal cameras, or just targeting glass for something like a normal vision camera, these piezos can be attached in different configurations to that lens and then vibrated effectively with ultrasonic frequencies to expel the contaminants that are on the surface.

So as I mentioned, this technology can be adapted to various lens shapes and aperture sizes. TI has worked on a few different designs for flat lens and curved lens. We do have some mechanical design guides that are available in My Secure Resources. At the end of this presentation, we'll go over some of the resources available and how to find those.

So this here is an animation example of a cylindrical piezo that is vibrating a flat lens. This is something we call a lens cover system, which means that there's actually a camera module sitting inside this lens cover system or behind this lens, which actually has the ultrasonic lens cleaning technology. It is also possible to integrate ULC directly into the camera module, but that has a different set of challenges associated with it.

So ULC can clear water, ice, dust, or even some mud. ULC is very effective for expelling water. The piezo can actually be driven basically like a resistor to create heat, so we do see in a lot of cameras or LiDAR systems today in a car, for example, that there are heating elements in those camera modules. When ULC is adapted into a camera module, it can actually replace those heating elements so they're no longer needed. We can use the piezo to heat the lens system and then, of course, drive it with a higher frequency to then expel the water that's on the surface.

We can use this combination of heating and expulsion as well for things like mud. So we can do some expulsion cycles to eliminate as much of the material as possible, do some heating to dehydrate, and then do another expulsion cycle to expel the remaining contaminant on the lens surface.

So what does the typical ULC system look like? There are really two separate components to this. One is the electronics portion. And then the other is the actual mechanical lens cover system is what we call it.

So from the electrical side, we have a two-chip solution, the ULC1001 and then the DRV290x family. So the ULC1001 is a DSP controller with IV sensing and PWM output. This is basically the brain of the operation. It provides the output signals to drive the lens. It also has a feedback path, so it can listen back to the lens so to speak.

This is part of how we do automatic contaminant detection. So the ULC1001 can detect if there is a mass on the lens. It can also detect if there are any faults on the lens, for example, a chip or a crack. All of the algorithms for ultrasonic lens cleaning are stored in this DSP, and the output from this device effectively goes to a class D amplifier, which is what is the DRV290x family. That amplifies the signal, which then drives the piezo transducer.

So in the right hand side, you see the mechanical lens cover system. This is where you have your camera module, the piezo transducer, the lens cover, and some form of a housing for the whole system. Now, to look at what this basically looks like in real life. So this on the left hand side is we have the electronics portion. This is a PCB.

Footprint is depending on the system somewhere roughly around 15 by 25 millimeters for ultrasonic lens cleaning. And then on the right hand side is we have one example of a lens cover system with the camera module inside of it.

And we can go ahead and look at what this looks like in an exploded view. So as I mentioned before, there are many different types of lens cover systems, different geometries, different ways to bond the piezo to the glass and the housing. This is one example of a system that uses a ring transducer with a metal bracket to interface the transducer to a curved lens. So we've got basically a screw-on housing cap, the curved lens, the metal bracket, a ring transducer, the base housing, the camera module, and then, of course, the ultrasonic lens cleaning PCB.

So I'll go ahead and review the resources we have. We've got a lovely product portfolio overview. If you just go to TI.com/ULC, you'll see that we have most of these resources there. The ULC1001 can be found at this product link. At that link, we also have a request link to get more information so you can get access to the mechanical design guide I mentioned. You can also get access to the full product data sheet.

We have a video that shows some of the applications for ultrasonic lens cleaning, as well as some of the demos. We have an interview from CES 2023 that goes a little bit more into depth on ultrasonic lens cleaning and, of course, shows our demos at CES as well.

And then we have two blogs. One is an introductory technical article called "What is Ultrasonic Lens Cleaning Technology?" This discusses a little bit more depth of how ultrasonic lens cleaning works but still sort of keeps it as an introductory high level. We have another detailed technical article called "Ultrasonic Lens Cleaning-- A Solid State Technology You Didn't Know You Needed." This article goes a lot more in depth on ULC and actually discusses some of the methods of how to implement ultrasonic lens cleaning.

And as I mentioned before, we do have a request link, which will give you access to the full datasheet, our evaluation module, the LCS design guides, and more. That request link can be found at the product folder for ULC1001.

So I see we have a question. What are typical applications? Are there applications other than cameras? So absolutely, we have-- this really can be used in any type of camera or sensor where there is some form of a lens, which we can actually vibrate to expel. So the first market that this technology was developed for is camera lenses, but we are looking into LiDAR as well.

We're looking at some other sort of roof sensors we've had early discussions around for automotive. Really, this could be implemented in a wide variety of applications, not just in automotive, but in manufacturing and industrial settings as well.

Another question. The frequency range is 40 kilohertz to 300 kilohertz. As Kelly mentioned, that's correct. We support a wide range of frequencies. Some designs do go a little bit lower than 40 kilohertz. Usually, there's no audible noise from the actual ultrasonic lens cleaning, but depending on how the vibrations are isolated, those vibrations can have some harmonics, or they could have some residual transferring of vibrations that go to housing, which then could actually create some noise. But in principle, there should not be any noise or audible noise from ultrasonic lens cleaning because it's out of our hearing range.

So there's a question. Is it OK to use plastic material lenses? We have done some simulations for polycarbonate, I believe. In theory, it is possible. It just requires-- you need to simulate, find sort of what the proper piezo transducer would be, the correct geometry. It also depends on the lens thickness. So there's a lot of considerations to be taken to effect before we could say it could or couldn't be done with a plastic lens. But in theory, or in principle, it should be possible with the correct geometry and planning.

Are there any more questions? So we have a question. What do you think the future of ULC technology will look like? Eventually, we think this technology will be adopted into most cameras or sensors. We've had requests from the medical field for sensors that are inside lab equipment that can get over time dusty. And instead of having these shipped and serviced and taken apart, which can cost thousands of dollars, they can implement ULC into those systems to keep them in service for decades.

Along those lines, we think eventually ULC will be adopted into personal electronics, even smartphones, action cameras, really any place that a camera sensor could get dirty. Personally, I believe that eventually as ULC becomes more proliferate, we'll see it in literally every single camera.

So we have another question. What is power needed for such a solution? Can a lower cost MCU be used instead of a DSP? So the power needed for the system really depends on the geometry. We have some design-- and it also depends on the type of piezo transducer used and the approach. So we have some working designs that operate with one watt of continuous power, or three to five watts of peak power. We also have some designs that operate with 15 to 20 watts of power.

So it really just depends on things like the glass thickness, the piezo transducer used, and the whole overall design approach. Can a lower cost MCU be used instead of a DSP? So there's a lot more than just having some kind of DSP there. There are a lot of algorithms involved in ultrasonic lens cleaning.

We use those for the contaminant detection. We use those for calibrating actually-- so every single lens cover system will be slightly different. There's always manufacturing variability, especially because this involves some assembly process for ULC. The ULC1001 we have actually can account for that.

So we can do a characterization of every single LCS and basically finding the sweet spot for driving the system. We have algorithms that are already integrated for different cleaning patterns, for de-icing, for clearing mud, for clearing water. So it's a little bit more sophisticated in what is offered in ULC1001. There's a lot of proprietary algorithms as well that could not be basically replaced by different low cost MCU.

We have another question. What is the largest area that can be cleaned? And as-- let's see if Kelly already answered this one. So there's not necessarily a limitation. There are different approaches to ultrasonic lens cleaning.

So some of the approaches we've seen, which involve, for example, a single piezo transducer to drive-- we've started to see a limitation around 40 millimeters. There are other approaches, which use multiple piezos. And you can learn a little bit more about this in the technical article, the detailed technical article here, "Ultrasonic Lens Cleaning-- Solid State Technology You Didn't Know You Needed."

So there are kind of direct vibration approaches to ULC. There's also approaches that use lamb waves and saw waves. Those can be used for larger glass surfaces for things like LiDAR. They don't necessarily vibrate the entire glass as much as they send waves through the glass or on the surface to excite the contaminants directly instead. So for those reasons, depending on piezo placement, in theory, it's possible to clear much larger surfaces as well.

So we have another question. Does this cause the camera image to have jitter due to ultrasonic vibration? How is this handled? So a ultrasonic lens cleaning system is driving at a very high frequency, and the vibration that the piezo is actually vibrating is really, really, really tiny. We're talking like less than 10 microns.

The principle of ultrasonic lens cleaning is that we're resonating this class in specific-- by applying a frequency that is at the natural frequency of the system. And so when we resonate, we're literally causing high acceleration points at specific points on the lens surface itself. So in fact, even though the piezo is the thing that's causing the vibration, the outer lens will vibrate in its acceleration points more than the actual piezo does.

And that said, if that's isolated well, the vibration does not have to transfer to the optical sensor. And again, it's still even in the highest acceleration points, we're talking like less than 10 microns. So it's a very small amount of vibration, and the thing that we do see, though, is while you're doing ultrasonic lens cleaning, and there's a contaminant on the surface, you will see that contaminant expel. And that contaminant expelling could create sort of a cloud of vapor in front of the camera.

So for that sort of instantaneous moment, there will be some impact to the image. But if you had something like a wiper, you'd be dealing with that as well. If you wipe water off, in the moment that you're wiping the water off, you'll have the wiper getting in the way of the camera image.

So the voltage rail needed for the DRV part, that's another question. The device supports from basically 0 volts all the way to 50 volts. We do have a 12 volt rail needed for the device to operate. But the actual driving voltage is very flexible. And so it depends on the actual lens cover system.

So we have designs that operate-- we've seen designs that operate as low as 20 volts or 18 volts. We have designs that operate with even a much higher voltage after the LC filter even getting an effective voltage over 100 volts. So it really depends on the actual mechanical design. And as Kelly mentioned, we have our flat lens uses 18 volts rail, and then we've also seen other lenses that operate with 30 volts, 20, 25 volts.

Lastly, another question, what type of algorithms are implemented in ULC1001? So we have, as I mentioned before, various algorithms in the device. Some are related to characterization to make sure that when we're doing ULC, it's really optimal for every single individual system, despite manufacturing variability. The device can account for that.

We also have algorithms integrated into the device for contaminant detection, so being able to tell with variable levels of sensitivity if there is something on the surface of the lens. We can also do temperature detection. So for a piezo transducer, there's something called the Curie point, which is basically a temperature at which if you exceed that temperature, the piezo transducer will completely lose its polar property. It won't function anymore as a piezo.

And so for example, if you have a car that's sitting in the sun, and you also start to drive the system for whatever reason continuously, or you accidentally for a heating cycle, there's a chance that you could drive this system past the Curie point for the piezos, and you're going to permanently damage the system. So having that integrated temperature detection or temperature sensing effectively protects the system from those permanent damages.

We have a question. Will the ULC and DRV parts be automotive qualified? Yes, we do have those in the works. Today, we have a commercial version of ULC and DRV devices in production, and we do have those automotive qualifications underway for both devices.

We have another question. Can we recommend any piezo manufacturers to our customers? So we do have different piezo manufacturers that we've partnered with. We have in our design guides and in the BOM for our upcoming EVMs, you'll see some of the providers for those manufacturers. We're also working on a kind of a third party ecosystem page for TI.com/ULC. So eventually, in the upcoming months, we'll start to build a page for all the different third party partners that we have from system integration to supply, et cetera.

We welcome everybody to ask any questions they have. Will there be a development kit available? So that's a great question. Today, we have behind My Secure Resources. So again, you do need to request access to this. Once you get access to this, you will have an EVM available today. That is an-- maybe I can actually pull it up just to show everybody.

I'll go ahead and pull that up so everyone can see what that looks like. So if you go into TI.com and My Secure Resources, and ULC Design Folder. This is what that looks like. We have a section for ULC documentation.

This is where you can find the full data sheet, the EVM user guide, a wonderful introductory white paper to ultrasonic lens cleaning. We have a ULC hardware and software section. So the question was around a dev kit. So today, we have available the ULC1001-DRV290x EVM. This is the electrical portion of a ULC system.

So this is meant to be used if you already have a ULC mechanical system. This can drive various mechanical designs. Coming soon, we have two EVMs that will include basically a bundle of the ULC1001 EVM and a flat LCS or a bundle of the ULC1001 EVM and a curved LCS. So if you're just starting ultrasonic lens cleaning, you haven't seen it before, you're not familiar with how it works , this is really the place to get started. We're expecting to have those online soon.

We have a question. Do you have any automotive customers building production intent designs awarded business by an OEM? So I can't speak about that publicly. I will say that we are fairly confident to see ultrasonic lens cleaning in the market towards the end of this year or early next year.

[INAUDIBLE]

We don't have too much time left. So I encourage anybody that has a question to please feel free and type in the chat. A lot of great questions so far. If anybody joined late, this presentation will actually be recorded and available on ti.com/npu.

We've got a question. How bulky or what volume will the ULC add to a design? So again, this is really dependent on the ULC design. We do have this example here. So you can see what kind of a fully integrated-- sorry, not fully integrated, a lens cover system looks like. This is what we call a lens cover system.

So there's a camera module seated behind a lens cover. It's really adding minimal space. The PCB is-- this example here is around 15 by 25 millimeters, something that can be easily tucked behind a camera module. In the example of a car application, this lens cover and housing is something that could be even integrated into the car itself or the housing or the body. So we see sort of a very minimal footprint added by ultrasonic lens cleaning.

And here is the exploded view again.

All right, thank you, Avi. And thank you for attending today's NPU webinar. The recording-- you know what, I will take a pause because I think we got one last minute question.

We've got a question. With a small footprint, what kind of heat dissipation be required? So the heat-- these are actually fairly low power systems. Most of the heat generated will be from the transducer itself. And usually, that will be somewhat deliberate, for example, if you're trying to melt ice.

So in terms of heat dissipation from the piezo transducer, we do have temperature sensing, something that the device takes that heat into consideration before-- [AUDIO OUT] if it needs to what we call a cooling cycle or a delay to prevent the system from overheating, that will be managed by the ULC1001.

And then in terms of the PCB itself, this really depends on the intent of how often you're going to be cleaning, the environment it's cleaning in, how your system is built, so the size of the piezo transducer that you're driving, how much power you're driving with. So it's a very system dependent question that I can't answer so generically so to speak. But I will say that for most applications, we intend for this to be able to be integrated directly into the existing camera housing or module without the necessity for a large sink or kind of really excessive thermal consideration. All right.

All right, thank you, Avi.

My pleasure.

Thank you for attending today's NPU webinar. The recording and PDF version of the slides will be available at ti.com/npu on Monday, January 30. See you next week for our next topic, industry's lowest jitter and fastest response Hall effect latch. Have a great day.

Thanks, Avi.

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