lock screen

A lock screen is a computer user interface element used by various operating systems. They regulate immediate access to a device by requiring the user to perform a certain action in order to receive access, such as entering a password, using a certain button combination, or performing a certain gesture using a device's touchscreen. There are various authentication methods to get past the lock screen, with the most popular and common ones being personal identification numbers (PINs), the Android pattern lock, and biometrics (e.g. Touch ID and facial recognition).{{Cite book|last1=Harbach|first1=Marian|last2=De Luca|first2=Alexander|last3=Egelman|first3=Serge|title=Proceedings of the 2016 CHI Conference on Human Factors in Computing Systems |chapter=The Anatomy of Smartphone Unlocking: A Field Study of Android Lock Screens |date=7 May 2016|pages=4806–4817 |location=New York, NY, USA|publisher=ACM|doi=10.1145/2858036.2858267|isbn=978-1-4503-3362-7|doi-access=free}}

Depending on the operating system and device type, a lock screen can range from a simple login screen, to an overview screen with the current date and time, weather, recent notifications, playback controls for media being played in the background (typically music), shortcuts to applications (such as the camera), and optionally, the contact information of the device's owner (which can be used in the event that the device is lost or stolen, or during a medical emergency).{{Cite web|url=https://www.cnet.com/how-to/first-responders-can-help-you-even-when-your-phone-is-locked/|title=First responders can help you even when your phone is locked|last=Cipriani|first=Jason|website=CNET|language=en|access-date=3 January 2020}}{{Cite web|url=https://www.phonearena.com/news/How-to-add-owner-info-on-your-Android-lock-screen-helpful-in-case-you-lose-your-device_id66968|title=How to add owner info on your Android lock screen (helpful in case you lose your device)|last=T|first=Florin|website=Phone Arena|date=9 March 2015 |language=en-US|access-date=3 January 2020}}{{Cite web|url=https://www.androidcentral.com/lock-screen-customization-dead|title=Lock screen customization is dead|date=18 June 2018|website=Android Central|language=en|access-date=3 January 2020}}

Lock screens by platform

=Mobile operating systems=

Mobile operating systems that run on smartphones and tablets typically use a gesture based lock-screen. Phones manufactured by Neonode were unlocked by swiping to the right on its touchscreen. Apple's iOS, used by the iPhone and iPad lines, utilized a similar unlock mechanism until iOS 10, with an on-screen slider slid to the right. Beginning on iOS 5, sliding in the other direction sends the user directly to the camera app. On iOS 7, the slider widget was removed as part of a larger overhaul of the iOS interface, and users could now swipe from any point on the screen. The lock screen also displays a clock, notifications, and provides audio playback controls.{{cite web|title=The 5 best features in Apple's iOS 5|url=http://www.pcworld.com/article/229866/The_5_best_features_in_Apple_iOS_5.html|publisher=PC World|accessdate=13 February 2013}}{{cite web|title=Get to know iOS 7: Design changes|url=http://www.macworld.com/article/2048733/get-to-know-ios-7-design-changes.html|work=MacWorld|accessdate=4 December 2013}} iOS 10 made major changes to the lock screen, replacing the sliding gesture with pressing the Home button. Swiping is still used to access the camera, as well as an additional page to the left with widgets.{{Cite news|url=http://www.techradar.com/how-to/how-to-use-the-lock-screen-in-ios-10|title=How to use the Lock screen in iOS 10|work=TechRadar|access-date=13 November 2017|language=en}}{{Cite news|url=https://www.cnet.com/how-to/heres-how-to-navigate-the-ios-10-lock-screen/|title=How to use the iPhone's new, confusing lock screen|work=CNET|access-date=13 November 2017|language=en}} As the iPhone X and iPad Pro do not have physical home buttons, the user must swipe upwards from the bottom of the screen instead.{{Cite magazine|url=https://www.wired.com/2017/11/review-iphone-x/|title=iPhone X Review: All Up In Your Face ID|last=Pierce|first=David|magazine=Wired|access-date=13 November 2017|language=en-US}}{{Cite web|url=https://www.pcmag.com/feature/365215/how-to-navigate-the-ipad-pro-without-a-home-button|title=How to Navigate the iPad Pro (Without a Home Button)|last=Whitney|first=Lance|website=PCMAG|language=en|access-date=4 January 2020}}

At first, Android did not use a gesture-based lock screen, electing to require the user to press the phone's Menu button. On Android 2.0, a new gesture-based lock screen was introduced, displaying two icons: one for unlocking the phone, and one for setting the volume mode, activated by dragging the relevant icon to the center of the screen on a curve (similarly to a rotary dial). On Android 2.1, the rotary dial was replaced by two tabs on either end of the screen.{{cite web|title=Android: A visual history|date=7 December 2011 |url=https://www.theverge.com/2011/12/7/2585779/android-history|publisher=The Verge|accessdate=14 February 2013}} Android 3.0 introduced a new design: a ball with a padlock icon is dragged to the outside of a circular area.{{cite web|title=Ars reviews the Motorola Xoom|date=7 March 2011 |url=https://arstechnica.com/gadgets/2011/03/ars-reviews-the-motorola-xoom/3/|publisher=Ars Technica|accessdate=14 February 2013}} On 4.0, the option to unlock straight to the camera is provided, while 4.1 adds the ability to unlock into a Google Search screen by dragging up.{{cite web|title=Android 4.0 ICS demo: Active voice dictation, Unlock to camera, and more|date=17 November 2011 |url=http://www.slashgear.com/android-4-0-ics-demo-active-voice-dictation-unlock-to-camera-and-more-17196349/|publisher=SlashGear|accessdate=14 February 2013}}{{cite web|title=Android 4.1 and Android 4.2 combine to make the ultimate Jelly Bean|url=http://www.techradar.com/reviews/pc-mac/software/operating-systems/android-jelly-bean-1087230/review/1#articleContent|publisher=TechRadar|accessdate=14 February 2013}} Android 4.2 makes additional changes to the lock screen, allowing users to add widgets to pages accessible on the lock screen by swiping from the left edge of the screen. The camera is accessed in a similar manner by swiping from the right edge of the screen. Android also allows devices to be locked using either a password, passcode, a pattern on a grid of 9 circles, fingerprint sensing, or facial recognition.

Android distributions by other manufacturers typically use different lock screen designs than what stock Android utilizes; some versions of HTC's Sense used a metallic ring dragged from the bottom of the screen to unlock the phone, and also allows users to launch apps by dragging their respective shortcut icon into the ring instead.{{cite web|title=HTC Desire X review: Needs and wants|url=http://www.gsmarena.com/htc_desire_x-review-847p4.php|publisher=GSM Arena|accessdate=14 February 2013}} On Samsung devices, the lock screen involves dragging in any direction from any location on the screen (TouchWiz Nature devices, such as the Galaxy S III and S4, are also accompanied by a visual effect, such as a pond ripple or lens flare); similarly to HTC's lock screen, app shortcuts can be dragged up from the bottom of the screen to unlock directly into them.{{cite web|title=Samsung Galaxy S III Android 4.2.2 firmware leaked, reveals some Galaxy S4 software features|url=http://gadgets.ndtv.com/mobiles/news/samsung-galaxy-s-iii-android-422-firmware-leaked-reveals-some-galaxy-s4-software-features-369596|work=NDTV|date=21 May 2013 |accessdate=18 June 2013}}{{cite web|title=Samsung I8190 Galaxy S III mini review: The Halfling|url=http://www.gsmarena.com/samsung_galaxy_s_iii_mini-review-857p4.php|publisher=GSM Arena|accessdate=14 February 2013}}

=PC operating systems=

File:Windows 11 lock screen.png

Windows NT has offered the ability for users to "lock" their computers by displaying a login window, which requires the active user's password to be entered to re-gain access to the system. Since Windows XP, the lock function has also been bound to the keyboard shortcut {{keypress|Win|L}}.{{cite web|title=How to Quickly Lock Your Computer and Use Other Windows Logo Shortcut Keys|url=http://support.microsoft.com/kb/294317|publisher=Microsoft|accessdate=13 February 2013}} On Windows 8, the lock screen was re-designed to closer resemble those used by mobile operating systems; users can choose a distinct wallpaper for use on the lock screen, which now also displays a clock, calendar events, and notifications from other apps. The screen can be dragged upwards with a mouse or touchscreen to unlock the device.{{cite web|title=Windows 8 Feature Focus: Lock Screen|url=http://winsupersite.com/article/windows8/windows-8-feature-focus-lock-screen-144656|publisher=SuperSite for Windows|accessdate=14 February 2013}} Windows 10 maintains this design, whilst adding the ability to use the Cortana voice assistant from the lock screen, and support for slide shows, and the "Windows Spotlight" service to retrieve daily wallpapers and optionally receive advertising and suggestions related to the wallpaper.{{Cite news|url=https://www.pcmag.com/article/348390/how-to-use-and-tweak-your-windows-10-lock-screen|title=How to Use and Tweak Your Windows 10 Lock Screen|work=PCMAG|access-date=13 November 2018|language=en}}{{Cite news|url=https://www.theverge.com/2015/4/29/8514345/windows-spotlight-lock-screen-with-ads|title=Microsoft wants to put ads on the Windows 10 lock screen|work=The Verge|access-date=13 November 2018}}

Screen locking functionality is also built into screensaver systems on some Unix-like operating systems, such as XScreenSaver{{cite web|last=Zawinski|first=Jamie|title=XScreenSaver FAQ|url=http://www.jwz.org/xscreensaver/faq.html|accessdate=13 February 2013}} and gnome-screensaver.{{cite web|title=GNOME screen lock ineffective in openSUSE Linux – Update|url=http://www.h-online.com/open/news/item/GNOME-screen-lock-ineffective-in-openSUSE-Linux-Update-928794.html|publisher=The H|accessdate=13 February 2013}}

Monetization

Particularly on Android, custom lock screen software can be designed to replace the default lock screen with one that displays advertising or otherwise sponsored content.{{Cite web |last=Rogerson |first=James |date=1 December 2017 |title=Google has finally banned lock screen ads on Android |url=https://www.techradar.com/news/google-has-finally-banned-lock-screen-ads-on-android |access-date=6 July 2022 |website=TechRadar |language=en}}{{Cite web |last=Pierce |first=David |date=5 July 2022 |title=Apps and advertisers are coming for your lock screen, and it's going to be exhausting |url=https://www.theverge.com/2022/7/5/23195827/lockscreen-content-apple-ios-16-glance |access-date=6 July 2022 |website=The Verge |language=en}} Amazon's Android-based Kindle Fire tablets display notifications of "special offers" on its lock screen, unless users purchase a more expensive SKU of the device which disables this feature.{{Cite magazine |last=Gilbertson |first=Scott |title=Which Amazon Fire Tablet Is Best for You? |language=en-US |magazine=Wired |url=https://www.wired.com/story/best-amazon-fire-tablet/ |access-date=6 July 2022 |issn=1059-1028}} In 2016, Amazon began to market discounted smartphones exclusive to Amazon Prime subscribers that are subsidized by "special offers" and pre-loaded Amazon apps.{{Cite web |last=Goode |first=Lauren |date=29 June 2016 |title=Amazon will start subsidizing Android phones with 'special offer' ads on the lock screens |url=https://www.theverge.com/circuitbreaker/2016/6/29/12054818/amazon-prime-special-offers-ads-subsidized-android-unlocked-smartphones |access-date=6 July 2022 |website=The Verge |language=en}} In November 2017, Google Play Store prohibited apps from displaying advertisements on the lock screen unless the app is specifically designed to replace the lock screen, citing issues with adware embedded in unrelated apps.{{Cite news |title=Google bans Android developers from adding lock screen ads |language=en-us |work=Ars Technica |url=https://arstechnica.com/gadgets/2017/12/google-bans-android-developers-from-adding-lock-screen-ads/ |access-date=1 December 2017}} The Indian company Glance produces a lock screen replacement that displays a content feed on the lock screen, which is monetized via advertising.

Patent litigation

File:Neonode-n2.jpg for Apple's iOS lock screen.]]

Apple holds several patents related to the sliding lock screen used by its iOS devices: it was granted {{US patent|7657849}} in 2010, and {{US patent|8046721}} in 2011, describing a system that involves continuously dragging an image to a certain point to unlock the device. As part of ongoing patent wars between numerous companies surrounding patents related to mobile devices, Apple asserted these patents in several patent infringement lawsuits outside the United States with competing vendors.{{cite magazine|title=How Patent Battles Threaten the Simple Act of Unlocking a Phone|url=https://www.wired.com/gadgetlab/2012/02/smartphone-slide-to-unlock-google/|magazine=Wired|accessdate=14 February 2013|last1=Isaac |first1=Mike }}

Apple's lawsuits with Samsung in the Netherlands and HTC in the United Kingdom both led to failure: both courts ruled the patents to be invalid, citing the similar lock screen on the N1, a mobile phone manufactured by the Swedish company Neonode, as prior art for Apple's design. The British court specifically ruled that Apple's lock screen{{Cite web|last=shilpa|first=gupta|date=18 August 2020|title=Ensure the privacy with how to lock apps in iPhone – Web Blog Ensure the privacy with how to lock apps in iPhone|url=https://www.ineedaweb.com/how-to-lock-apps-in-iphone/|archive-url=|archive-date=|access-date=29 August 2020|website=Web Blog|language=en-US}} was an "obvious improvement" over that of the Neonode N1 due to its additional visual feedback through an on-screen slider graphic (unlike the N1, which only displayed a written instruction explaining the gesture).{{cite web|title=Apple Awarded Second Slide-to-Unlock Patent, Targeting HTC?|url=https://www.pcmag.com/article2/0,2817,2395316,00.asp|publisher=PC Magazine|accessdate=14 February 2013}}{{cite news|title=HTC defeats Apple in swipe-to-unlock patent dispute|date=4 July 2012 |url=https://www.bbc.co.uk/news/technology-18709232|publisher=BBC News|accessdate=14 February 2013}} Early work on touchscreen technology from the University of Maryland Human – Computer Interaction Lab was also cited as prior art,{{cite web|title=Apple touch-screen patent war comes to the UK|date=10 December 2011 |url=http://www.channel4.com/news/apple-touch-screen-patent-war-comes-to-the-uk|accessdate= 3 December 2015}} in particular a 1991 touchscreen slider developed by Catherine Plaisant.{{cite web|title=1991 video of the HCIL touchscreen toggle switches (University of Maryland)| website=YouTube | date=30 November 2011 |url=https://www.youtube.com/watch?v=wFWbdxicvK0|accessdate=3 December 2015}}

In January 2012, Apple won a permanent injunction from a German court after it ruled that Motorola Mobility violated the patents on some of its recent devices (although the Motorola Xoom tablet was ruled not to have infringed on the patent). However, Apple was warned that they would have been required to put up a bond as insurance if they were to allow the injunction to take effect, and any potential sales ban as a result would be limited to Germany.{{cite web|title=Apple slides and blocks Motorola devices over slide-to-unlock|url=http://news.cnet.com/8301-13506_3-57379386-17/apple-slides-and-blocks-motorola-devices-over-slide-to-unlock/|publisher=CNET|accessdate=14 February 2013}}