See-through display

Last updated
An optical combiner for a see-through display

A see-through display or transparent display is an electronic display that allows the user to see what is shown on the screen while still being able to see through it. The main applications of this type of display are in head-up displays, augmented reality systems, digital signage, and general large-scale spatial light modulation. They should be distinguished from image-combination systems which achieve visually similar effects by optically combining multiple images in the field of view. Transparent displays embed the active matrix of the display in the field of view, which generally allows them to be more compact than combination-based systems.

Contents

Broadly, there are two types of underlying transparent display technology, absorptive (chiefly LCDs) and emissive (chiefly electroluminescent, including LEDs and "high-field" emitters). Absorptive devices work by selectively reducing the intensity of the light passing through the display, while emissive devices selectively add to the light passing through the display. Some display systems combine both absorptive and emissive devices to overcome the limitations inherent to either one. Emissive display technologies achieve partial transparency either by interspersing invisibly small opaque emitter elements with transparent areas or by being partially transparent.

History

The development of practical transparent displays accelerated rapidly around the end of first decade of the 21st century. An early commercial transparent display was the Sony Ericsson Xperia Pureness released in 2009, although it did not succeed in the market due to the screen not being visible outside or in brightly lit rooms. Samsung released their first transparent LCD in late 2011, and Planar published a report on a prototype electroluminescent transparent display in 2012. [1] Not long after, UK-based Crystal Display Systems began to sell transparent LCDs remanufactured from conventional LCD displays. [2] LG demonstrated a transparent LCD in 2015. [3] In the later part of the 2010s, transparent OLEDs started to appear. LG, Prodisplay, and taptl, for example, use conventional LCD technology. LG also uses OLED technology. [4] [5] LUMINEQ transparent displays manufactured by Beneq are Thin Film Electroluminescent Displays enabled by Atomic layer deposition (ALD). This display technology was used by Valtra in 2017 to develop its SmartGlass [6] Head-Up Display [7] on tractors. Samsung and Planar Systems previously made transparent OLED displays but discontinued them in 2016. [8] Prodisplay used both OLED and LCD technology, but no longer makes transparent OLED displays. [9] [10] [11] [12] [13] [14]

How it works

There are two major see-through display technologies, LCD and LED. The LED technology is older and emitted a red color, OLED is newer than both using an organic substance. Though OLED see-through displays are becoming more widely available, both technologies are largely derivative from conventional display systems. In see-through displays, the difference between the absorptive nature of the LCD and emissive nature of the OLED gives them very different visual appearances. LCD systems impose a pattern of shading and colours on the background seen through the display, while OLED systems impose a glowing image pattern on the background. TASEL displays are essentially transparent thin-film Electroluminescent Displays with transparent electrodes. [15]

Pixel Pitch and Brightness:

Partial Reflection

A Partial Reflection Display shows an image by reflecting an image off a smooth transparent surface such as glass or specialty film. [17]

A device using a semi-reflective glass panel and a screen to create a see-through display Holomouseio Showcase.jpg
A device using a semi-reflective glass panel and a screen to create a see-through display

Partial Reflection Displays comparatively simple but are limited by the brightness of the reflected image needing to be considerably brighter than the light sources beyond the display.

A common example of partial reflective displays is in vehicular the Head-up display of a car or fighter jet. The Pepper's ghost illusion is a classic example that uses this technique passively.

Head-mounted displays

LCD

An LCD panel can be made "see-through" without applied voltage when a twisted nematic LCD is fitted with crossed polarizers. Conventional LCDs have relatively low transmission efficiency due to the use of polarizers so that they tend to appear somewhat dim against natural light. Unlike LED see-through displays, LCD see-throughs do not produce their own light but only modulate incoming light. LCDs intended specifically for see-through displays are usually designed to have improved transmission efficiency. Small scale see-through LCDs have been commercially available for some time, but only recently have vendors begun to offer units with sizes comparable to LCD televisions and displays. Samsung released a specifically see-through designed 22-inch panel in 2011. As of 2016, they were being produced by Samsung, LG, and MMT, with a number of vendors offering products based on OEM systems from these manufacturers. An alternative approach to commercializing this technology is to offer conventional back-lit display systems without the backlight system. LCD displays often also require removing a diffuser layer to adapt them for use as transparent displays.

The key limitation to see-through LCD efficiency is its linear polarizing filters. An ideal linear polarizer absorbs half of the incoming unpolarized light. In LCDs, light has to pass two linear polarizers, either in the crossed or parallel-aligned configuration.

LED

See-through OLED display Samsung Transparent OLED Display (24182257080).jpg
See-through OLED display

LED screens to have two layers of glass on both sides of a set of addressable LEDs. Both inorganic and organic (OLED) LEDs have been used for this purpose. The more flexible (literally and figuratively) OLEDs have generated more interest for this application, though as of July 2016 the only commercial manufacturer Samsung announced that the product would be discontinued. [18] OLEDs consist of an emissive and conductive layer. Electrical impulses travel through the conductive layer and produce light at the emissive layer. This is different from LCDs in that OLEDs produce their own light, which produces a markedly different visual effect with a see-through display. The narrow gap between the pixels of the screen as well as the clear cathodes within allows the screens to be transparent. These types of the screen have been notoriously difficult and expensive to produce in the past, but are now becoming more common as the method of manufacturing them is advancing. [19] OLED transparent displays generate their own light, but can not show black; this can be solved by the addition of a special LCD layer.

Passive transparent displays

MIT Researchers developed an inexpensive and passive transparent display system that uses nano-particles. [20]

Unlike transparent LCDs and OLEDs that requires integrated electronic modules to process visual signals or emit their own light, a passive transparent display uses a projector as the external light source to project images and videos onto a transparent medium embedded with resonance nanoparticles that selectively scatter the projected light. [21] This approach improves the deficiencies observed with transparent LCDs and OLEDs, such as high cost, difficulty of scaling in size, and delicate maintenance. [22] [23]

The MIT research is being commercialized by a startup company, Lux Labs, Inc. [24]

TASEL Displays

Lumineq TASEL displays are based on the Electroluminescent Display technology. [25] The TASEL glass panel consists of a luminescent phosphorous layer sandwiched between two transparent electrodes layers. The display emits light by itself and has a transparency of 80%. Unlike LCDs and LEDs using organic materials that will be effected by environments, TASEL displays are inorganic and immune to environments. One of the disadvantages of TASEL displays was not being capable of displaying more than one colour. [26]

Applications

Head-up display in an aircraft AIII in 1000ft.JPG
Head-up display in an aircraft

See-through displays can be used for:

  1. Brick-and-Mortar Store Windows: These displays offer highly effective advertising by transforming storefronts into dynamic visual experiences. This can be particularly advantageous for ad exchange platforms due to their high CPMs resulting from their effectiveness. [16]
  2. Billboards: Transparent displays on billboards allow creative advertising agencies to design ads that seamlessly blend video content with the background, creating eye-catching and innovative advertising campaigns. [16]
  3. Large Building Facades: Building owners can utilize transparent displays on facades to generate significant revenue through advertisements. These displays do not obstruct the view for residents, as the displays are transparent, maintaining the visibility of the outside scenery from inside the building. [16]
  4. augmented reality, and other applications such as shopping displays and more sophisticated computer screens. [27] [28]

See-through displays based on OLED or microLED technology may display black through the addition of an LCD, as they cannot do it on their own. This is because, in OLED and micro-LED, the OFF state corresponds to black (or in this case, transparent since there is no black background) and the ON state corresponds to white; this is because OLED and microLED pixels emit their own light. See-through LCDs cannot display whites because LCD pixels do not emit their own light, rather they selectively block light from a white backlight, although this could theoretically be fixed though the addition of a transparent monochrome microLED or OLED display. In LCDs, this is because, in the OFF state, the pixels turn off, allowing light from a backlight to pass through, while in the ON state, the pixels turn on, blocking light. [29] [30] [31]

MIT Researchers were working on creating Transparent Displays inexpensively using nano-particles. [32] As of 2019, the MIT research was being commercialized by a startup company, Lux Labs, Inc. [33]

Augmented reality

See-through screens are an emerging market that has several potential uses. Cell phones, tablets and other devices are starting to use this technology. It has an appealing appearance but more importantly it is also effective for augmented reality applications. The device can add its own twist to what is behind the screen. For example, if you look through a tablet with a see-through display at a street, the device could overlay the name of the street onto the screen. It could be similar to Google street view, except in real-time. For example, Google Translate has a feature that allows the user to point the camera at a sign or writing in another language and it automatically displays the same view, but with the writing in the language of your choosing. This could be possible with see-through displays as well.

A device using a transparent display will have much higher resolution and will display much more realistic augmented reality than video augmented reality, which takes video, adds its own supplement to it, and then displays that onto the screen. [27] It could be simpler to display the addition onto the see-through screen instead. The Microsoft HoloLens is an application of this idea.

Retail

These displays are also used in shop windows. The shopping windows show the product on the inside as well as show text or advertisements on the glass. [28] This type of showcase is becoming more popular as see-through screens are becoming cheaper and more available.

Event stage

A transparent LED display can be used by stage designers and event producers to realize creative holographic-like visual effects.

See also

Related Research Articles

<span class="mw-page-title-main">Liquid-crystal display</span> Display that uses the light-modulating properties of liquid crystals

A liquid-crystal display (LCD) is a flat-panel display or other electronically modulated optical device that uses the light-modulating properties of liquid crystals combined with polarizers to display information. Liquid crystals do not emit light directly but instead use a backlight or reflector to produce images in color or monochrome.

<span class="mw-page-title-main">Electroluminescence</span> Optical and electrical phenomenon

Electroluminescence (EL) is an optical and electrical phenomenon, in which a material emits light in response to the passage of an electric current or to a strong electric field. This is distinct from black body light emission resulting from heat (incandescence), chemical reactions (chemiluminescence), reactions in a liquid (electrochemiluminescence), sound (sonoluminescence), or other mechanical action (mechanoluminescence), or organic electroluminescence.

<span class="mw-page-title-main">Plasma display</span> Type of flat-panel display

A plasma display panel is a type of flat-panel display that uses small cells containing plasma: ionized gas that responds to electric fields. Plasma televisions were the first large flat-panel displays to be released to the public.

<span class="mw-page-title-main">OLED</span> Diode that emits light from an organic compound

An organic light-emitting diode (OLED), also known as organic electroluminescentdiode, is a type of light-emitting diode (LED) in which the emissive electroluminescent layer is an organic compound film that emits light in response to an electric current. This organic layer is situated between two electrodes; typically, at least one of these electrodes is transparent. OLEDs are used to create digital displays in devices such as television screens, computer monitors, and portable systems such as smartphones and handheld game consoles. A major area of research is the development of white OLED devices for use in solid-state lighting applications.

<span class="mw-page-title-main">Flat-panel display</span> Electronic display technology

A flat-panel display (FPD) is an electronic display used to display visual content such as text or images. It is present in consumer, medical, transportation, and industrial equipment.

<span class="mw-page-title-main">Television set</span> Device for viewing computers screen and shows broadcast through satellites or cables

A television set or television receiver is an electronic device for viewing and hearing television broadcasts, or as a computer monitor. It combines a tuner, display, and loudspeakers. Introduced in the late 1920s in mechanical form, television sets became a popular consumer product after World War II in electronic form, using cathode-ray tube (CRT) technology. The addition of color to broadcast television after 1953 further increased the popularity of television sets in the 1960s, and an outdoor antenna became a common feature of suburban homes. The ubiquitous television set became the display device for the first recorded media for consumer use in the 1970s, such as Betamax, VHS; these were later succeeded by DVD. It has been used as a display device since the first generation of home computers and dedicated video game consoles in the 1980s. By the early 2010s, flat-panel television incorporating liquid-crystal display (LCD) technology, especially LED-backlit LCD technology, largely replaced CRT and other display technologies. Modern flat-panel TVs are typically capable of high-definition display and can also play content from a USB device. In the late 2010s, most flat-panel TVs began offering 4K and 8K resolutions.

<span class="mw-page-title-main">LCD television</span> Television set with liquid-crystal display

A liquid-crystal-display television is a television set that uses a liquid-crystal display to produce images. It is by far the most widely produced and sold type of television display. LCD TVs are thin and light, but have some disadvantages compared to other display types such as high power consumption, poorer contrast ratio, and inferior color gamut.

<span class="mw-page-title-main">Field-emission display</span>

A field-emission display (FED) is a flat panel display technology that uses large-area field electron emission sources to provide electrons that strike colored phosphor to produce a color image. In a general sense, an FED consists of a matrix of cathode-ray tubes, each tube producing a single sub-pixel, grouped in threes to form red-green-blue (RGB) pixels. FEDs combine the advantages of CRTs, namely their high contrast levels and very fast response times, with the packaging advantages of LCD and other flat-panel technologies. They also offer the possibility of requiring less power, about half that of an LCD system. FEDs can also be made transparent.

<span class="mw-page-title-main">3D display</span> Display device

A 3D display is a display device capable of conveying depth to the viewer. Many 3D displays are stereoscopic displays, which produce a basic 3D effect by means of stereopsis, but can cause eye strain and visual fatigue. Newer 3D displays such as holographic and light field displays produce a more realistic 3D effect by combining stereopsis and accurate focal length for the displayed content. Newer 3D displays in this manner cause less visual fatigue than classical stereoscopic displays.

<span class="mw-page-title-main">Backlight</span> Form of illumination used in liquid crystal displays

A backlight is a form of illumination used in liquid-crystal displays (LCDs) that provides illumination from the back or side of a display panel. LCDs do not produce light by themselves, so they need illumination to produce a visible image. Backlights are often used in smartphones, computer monitors, and LCD televisions. They are used in small displays to increase readability in low light conditions such as in wristwatches. Typical sources of light for backlights include light-emitting diodes (LEDs) and cold cathode fluorescent lamps (CCFLs).

This is a comparison of various properties of different display technologies.

<span class="mw-page-title-main">Screen burn-in</span> Disfigurement of an electronic display

Screen burn-in, image burn-in, ghost image, or shadow image, is a permanent discoloration of areas on an electronic visual display such as a cathode-ray tube (CRT) in an older computer monitor or television set. It is caused by cumulative non-uniform use of the screen.

<span class="mw-page-title-main">Electroluminescent display</span>

Electroluminescent displays (ELDs) are a type of flat panel display created by sandwiching a layer of electroluminescent material such as gallium arsenide between two layers of conductors. When current flows, the layer of material emits radiation in the form of visible light. Electroluminescence (EL) is an optical and electrical phenomenon where a material emits light in response to an electric current passed through it, or to a strong electric field. The term "electroluminescent display" describes displays that use neither LED nor OLED devices, that instead use traditional electroluminescent materials. Beneq is the only manufacturer of TFEL and TAESL displays, which are branded as LUMINEQ Displays. The structure of a TFEL is similar to that of a passive matrix LCD or OLED display, and TAESL displays are essentially transparent TEFL displays with transparent electrodes. TAESL displays can have a transparency of 80%. Both TEFL and TAESL displays use chip-on-glass technology, which mounts the display driver IC directly on one of the edges of the display. TAESL displays can be embedded onto glass sheets. Unlike LCDs, TFELs are much more rugged and can operate at temperatures from −60 to 105 °C and unlike OLEDs, TFELs can operate for 100,000 hours without considerable burn-in, retaining about 85% of their initial brightness. The electroluminescent material is deposited using atomic layer deposition, which is a process that deposits one 1-atom thick layer at a time.

<span class="mw-page-title-main">AMOLED</span> Display technology for use in mobile devices and televisions

AMOLED is a type of OLED display device technology. OLED describes a specific type of thin-film-display technology in which organic compounds form the electroluminescent material, and active matrix refers to the technology behind the addressing of pixels.

<span class="mw-page-title-main">Quantum dot display</span> Type of display device

A quantum dot display is a display device that uses quantum dots (QD), semiconductor nanocrystals which can produce pure monochromatic red, green, and blue light. Photo-emissive quantum dot particles are used in LCD backlights or display color filters. Quantum dots are excited by the blue light from the display panel to emit pure basic colors, which reduces light losses and color crosstalk in color filters, improving display brightness and color gamut. Light travels through QD layer film and traditional RGB filters made from color pigments, or through QD filters with red/green QD color converters and blue passthrough. Although the QD color filter technology is primarily used in LED-backlit LCDs, it is applicable to other display technologies which use color filters, such as blue/UV active-matrix organic light-emitting diode (AMOLED) or QNED/MicroLED display panels. LED-backlit LCDs are the main application of photo-emissive quantum dots, though blue organic light-emitting diode (OLED) panels with QD color filters are now coming to market.

Time multiplexed optical shutter (TMOS) is a flat panel display technology developed, patented and commercialized by Uni-Pixel Displays, Inc. TMOS is based on the principles of total internal reflection (TIR), frustration of TIR (FTIR) and field sequential colour generation (FSC). This combination of features make it suitable for applications such as mobile phones, televisions and signalling systems.

The following table compares cathode-ray tube (CRT), liquid-crystal display (LCD), plasma and organic light-emitting diode (OLED) display device technologies. These are the most often used technologies for television and computer displays. A less detailed comparison of a wider variety of display technologies is available at Comparison of display technology.

<span class="mw-page-title-main">Universal Display Corporation</span> Developer and manufacturer of OLED technologies

Universal Display Corporation is a developer and manufacturer of organic light emitting diodes (OLED) technologies and materials as well as provider of services to the display and lighting industries. It is also an OLED research company. Founded in 1994, the company currently owns or has exclusive, co-exclusive or sole license rights with respect to more than 3,000 issued and pending patents worldwide for the commercialization of phosphorescent based OLEDs and also flexible, transparent and stacked OLEDs - for both display and lighting applications. Its phosphorescent OLED technologies and materials are licensed and supplied to companies such as Samsung, LG, AU Optronics CMEL, Pioneer, Panasonic Idemitsu OLED lighting and Konica Minolta.

<span class="mw-page-title-main">MicroLED</span> Emerging flat-panel display technology

MicroLED, also known as micro-LED, mLED or μLED is an emerging flat-panel display technology consisting of arrays of microscopic LEDs forming the individual pixel elements. Inorganic semiconductor microLED (μLED) technology was first invented in 2000 by the research group of Hongxing Jiang and Jingyu Lin of Texas Tech University (TTU) while they were at Kansas State University (KSU). The first high-resolution and video-capable InGaN microLED microdisplay in VGA format was realized in 2009 by Jiang, Lin and their colleagues at Texas Tech University and III-N Technology, Inc. via active driving of a microLED array by a complementary metal-oxide semiconductor (CMOS) IC. Compared to widespread LCD technology, microLED displays offer better contrast, response times, and energy efficiency.

References

  1. ↑ Antikainen, Mika; et al. (2012). "Transparent emissive thin-film electroluminescent display". SID Symposium Digest of Technical Papers. 31 (1): 885–887. doi:10.1889/1.1833096. S2CID   135606881.
  2. ↑ "LCD Transparent Displays and kits" . Retrieved 12 April 2021.
  3. ↑ Detwiler, Bill (8 January 2015). "CES 2015: LG Display shows off transparent LCD and curved plastic OLED screens". Techrepublic.com. Retrieved 12 April 2021.
  4. ↑ "LG 55EW5F-A: Transparent OLED Digital Signage | LG USA Business".
  5. ↑ "49WFB | Transparent Special Display | Large Format Displays | LG Canada". Archived from the original on 2018-04-06. Retrieved 2020-04-23.
  6. ↑ "SmartGlass – Key data always in your line of sight". Valtra Team. 2018-05-04. Retrieved 2021-03-11.
  7. ↑ "Valtra introduces revamped SmartGlass display". www.valtra.com. November 10, 2019. Retrieved 2021-03-11.
  8. ↑ "Samsung is killing off its line of see-through OLED TVS". 25 July 2016. Archived from the original on 2018-02-11. Retrieved 2020-04-23.
  9. ↑ "Transparent LCD Screen | Clear Transparent Screen Display Panel". Archived from the original on 2019-01-11. Retrieved 2019-01-11.
  10. ↑ "Samsung – Samsung". Archived from the original on 2019-01-11. Retrieved 2019-01-11.
  11. ↑ "With New See-Through Display, Samsung Puts the Window in Windows". core77. Archived from the original on February 5, 2013. Retrieved October 24, 2012.
  12. ↑ Kiger, Patrick (2012-09-20). "Can a TV be transparent?". How Stuff Works. Archived from the original on October 31, 2012. Retrieved November 14, 2012.
  13. ↑ "Interactive Transparent Displays". www.tap.tl. Archived from the original on November 19, 2015. Retrieved November 24, 2015.
  14. ↑ "The Magic of Transparent Technology". 31 January 2017. Archived from the original on 2019-06-16. Retrieved 2020-04-23.
  15. ↑ "Electroluminescent Displays – materiability" . Retrieved 2021-03-11.
  16. 1 2 3 4 "See Through Displays" . Retrieved 2024-06-03.
  17. ↑ Vivek Thakur and John Ferri. "TI DLP® Pico™ Technology for Aftermarket Head-up Displays
  18. ↑ "Samsung Display reportedly decided to halt transparent OLED production". OLED-Info. Archived from the original on 30 August 2016. Retrieved 16 August 2016.
  19. ↑ Freudenrich, Craig (March 24, 2005). "How OLEDs Work". HowStuffWorks.com. Retrieved October 17, 2012.
  20. ↑ Transparent Displays at MIT, 21 January 2014, archived from the original on 2020-02-10, retrieved 2019-12-13
  21. ↑ Sumner, Thomas (2014-01-21). "Video: Turning Your Windows Into Movie Screens". Science | AAAS. Archived from the original on 2019-12-13. Retrieved 2019-12-13.
  22. ↑ "MIT Researchers Created a New Type of Transparent Screen Display". Boston Magazine. 2014-01-22. Archived from the original on 2019-12-13. Retrieved 2019-12-13.
  23. ↑ "A Transparent Display Without Limits". news.yahoo.com. Archived from the original on 2019-10-07. Retrieved 2019-12-13.
  24. ↑ "Display Week: Die Fensterscheibe als Leinwand". c't Magazin (in German). 17 May 2019. Archived from the original on 2019-12-13. Retrieved 2019-12-13.
  25. ↑ Beneq. "Lumineq Technology - Electroluminescent Displays". lumineq.com. Retrieved 2021-03-11.
  26. ↑ "History of (EL) Electroluminescence". LightTapeUK. Retrieved 2021-03-11.
  27. 1 2 Kiyokawa, K.; Kurata, Y.; Ohno, H. (August 29, 2017). "An optical see-through display for mutual occlusion of real and virtual environments". Proceedings IEEE and ACM International Symposium on Augmented Reality (ISAR 2000). pp. 60–67. doi:10.1109/ISAR.2000.880924. ISBN   978-0-7695-0846-7. S2CID   9295821.
  28. 1 2 Kuo, Huei Pei et al. "See Through Display." 0157708 A1. June 30, 2011.
  29. ↑ "Transparent OLED Screen | Transparent Display". Archived from the original on 2020-01-12. Retrieved 2020-04-09.
  30. ↑ "LG Transparent OLED is a Huge Step into the Future of Display | News & Press | LG Information Display".
  31. ↑ "ITRI Fixes a 'Guilty Display Secret' at Touch Taiwan". 9 September 2019.
  32. ↑ Antonimuthu, Rajamanickam (22 January 2014). "Transparent Displays for Car Windshields and Window Advertisements". Archived from the original on 26 June 2014. Retrieved 23 January 2014– via YouTube.
  33. ↑ ClearBright Transparent Display, by LuxLabs.co, 20 May 2019, retrieved 2019-10-07
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.