Optical vs. laser mouse


Optical vs. laser mouse

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Whether you’re using it for work or play, our hands are generally cradling a mouse each day  — a mechanical mouse, that is. They scatter onto store shelves in all sorts of sizes, some of which are geared for the right-handed crowd, while a sprinkled few may sport an ergonomic design for the right-minded lefties.

Of all the features and form factors, you’ll find two base designs — one using an optical sensor, and one based on a laser. What’s the difference and which is better? Let’s have a look.

Guess what? All mice are optical

Modern mice are basically cameras. They constantly take pictures, although instead of capturing your face, they grab images of the surface underneath. These images aren’t meant for posting on social media, but instead are converted into data for tracking the peripheral’s current location on a surface. Ultimately, you have a low-resolution camera in the palm of your hand, otherwise known as a CMOS sensor. Combined with two lenses and a source of illumination, they track the peripheral’s X and Y coordinates thousands of times per second.

All mice are optical, technically, because they take photos, which is optical data. However, the one marketed as optical models rely on an infrared or red LED that projects light onto a surface. This LED is typically mounted behind an angled lens, which focuses the illumination into a beam. That beam is bounced off the surface, through the “imaging” lens that magnifies the reflected light, and into the CMOS sensor.

aukey km c4 gaming mouse
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The CMOS sensor collects the light, and converts the light particles into an electrical current. This analog data is then converted into 1’s and 0’s, resulting in more than 10,000 digital images captured each second. These images are compared to generate the precise location of the mouse, and then the final data is sent to the parent PC for cursor placement every one to eight milliseconds.

On older LED mice, you will find the LED pointing straight down, and shining a red beam onto the surface that’s seen by the sensor. Jump ahead years later, and the LED light is projected at an angle — and typically unseen (infrared). This helps the mouse track its movements on most surfaces.

Laser mice use an accurate, invisible beam

Meanwhile, Logitech takes the credit for introducing the first mouse to use a laser in 2004. More specifically, it’s called a vertical-cavity surface-emitting laser diode (or VCSEL) which is used in laser pointers, optical drives, barcode readers, and more.

This infrared laser replaces the infrared/red LED on “optical” models, but don’t worry. It won’t damage your eyes, because the lasers used by mice aren’t powerful (still, don’t press your luck and  stare at it for minutes at a time).

They’re also in infrared — outside the visible spectrum — so you won’t see an annoying red glow emanating from beneath your mouse.

Razer Mamba 2015
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At one time, laser models were believed to be far superior than “optical” versions. Over time, though, optical mice have improved, and they now work in a variety of situations with a high degree of accuracy. The laser model’s superiority stemmed from having a higher sensitivity than LED-based mice. However, unless you’re a PC gamer, that’s probably not an important feature.

The boxing match begins

So what’s the big difference between using an optical mouse, and a laser mouse, if the only difference is illumination?

For starters, both methods use the irregularities of a surface to keep track of the peripheral’s position. But a laser can go deeper into the surface texture without burning the material. This provides more information for the CMOS sensor and processor inside the mouse to juggle, and hand over to the parent PC.

For example, although glass is clear, there are still extremely small irregularities that can be tracked by a laser, enabling the host mouse to move across a glass table, but not perfectly. Meanwhile, we could place the latest optical mouse on the same surface, and it can’t track any movement. Place the glass surface on a black desktop, and the mouse still can’t track movement. Remove the glass, and the optical mouse works just fine.

Of course, the chances of your need to use a mouse on a glass surface are extremely rare, but it illustrates how the two illumination processes differ in performance. An LED will track the anomalies found on the upper-most layer of a surface, while a laser can go deeper to dig up extra positional details. Optical mice work best on non-glossy surfaces and mouse pads, while a laser mouse can function on just about any glossy or non-glossy surface.

Accuracy vs. sensitivity

The problem with laser-based mice is that they can be too accurate, picking up useless information such as the unseen hills and valleys of a surface. This can be troublesome when moving at slower speeds, causing on-screen cursor “jitter,” or what’s better known as acceleration. The result is some incorrect 1:1 tracking stemming from useless data thrown into the overall tracking mix used by the PC. The cursor won’t appear in the exact location at the exact time your hand intended. Although the problem has improved over the years, laser mice still aren’t ideal if you’re sketching details in Adobe Illustrator.

That said, jittering has nothing to do with the number of dots per inch a mouse can track per second. Instead, jittering is tied to everything that’s scanned by the laser, collected by the sensor, and handed over to the parent PC’s processor for on-screen cursor mapping. To alleviate some of the jitter, you could ditch cloth-based surfaces, and place a hard, dark surface underneath, so the laser isn’t picking up unnecessary junk data.

Another option would be to turn down the sensitivity. The CMOS sensor resolution in a mouse is different than a camera because it’s based on movement. The sensor consists of a set number of physical pixels aligned in a square grid. The resolution stems from the number of individual images captured by each pixel during a movement of one physical inch across a surface.

Because the physical pixels can’t be resized, the sensor can use image processing to divide each pixel into smaller pieces. That said, all mice have a set physical resolution, and the increased sensitivity stems from an algorithm within the sensor to increase the cursor movement on-screen even though your physical mouse movements remain unchanged. Thus, the closer you get to the base resolution, the less junk positional data the sensor in a laser-based mouse collects.

To put it more simply, lower sensitivities also result in more accurate movement.

Which is better?

It all depends on the application and surrounding. If you look at the Logitech G brand, you’ll notice that Logitech mostly focuses on LED-based mice when it comes to PC gaming. That’s because the customer base is typically sitting at a desk, and possibly even using a mouse mat designed for the best tracking and friction. PC gamers simply don’t want any errors in precision, present company included.

Yet laser-based mice aren’t exactly out of the picture. Logitech offers a handful that aren’t exactly gamer oriented, while its biggest competitor, Razer, lists a number of gamer-specific laser-based mice on its online store. Razer prefers laser technology because it offers higher sensitivity for lightning-quick movement in games. Overall, we don’t think that optical or laser technology is, by itself, enough to recommend any particular mouse for gaming.

Our recommendation is more definitive in mainstream and office use. A laser mouse might be ideal when you’re in a hotel room, in the living room lounging on the couch, trolling Facebook in Starbucks, stuck in a board meeting, and so on. The performance might be sporadic given the surface underneath, but with a laser mouse, you definitely have more surface options. Laser-based mice come in handy if you need to use your leg as a tracking surface, or when the office has nothing but shiny furniture that your LED-based mouse absolutely hates. Most high-end mice use a laser as a result.

Of course, they are generally more expensive as well. While laser is the more versatile technology, a decent optical mouse can do the job for less, so long as you plan to use it on dark, level, non-gloss surface.

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Published at Sun, 01 Apr 2018 00:00:11 +0000


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