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94-562: The Apollo Victoria Theatre is a West End theatre on Wilton Road in the Westminster district of London , across from London Victoria Station . (The theatre also has an entrance on Vauxhall Bridge Road .) Opened in 1930 as a cinema and variety theatre, the Apollo Victoria became a venue for musical theatre , beginning with The Sound of Music in 1981, and including the long-running Starlight Express , from 1984 to 2002. The theatre

188-399: A Compton 3 manual 15 rank theatre organ , played on the opening night by Reginald Foort. and the theatre also staged variety shows. The first show played also during the opening was Hoop-La. Frederic Curzon was the organist from 1934 until 1938. Variety quickly gave way to a specialisation in film performances, with occasional performances by big bands . In June 1939, the cinema was one of

282-563: A GaAs p-n junction light emitter and an electrically isolated semiconductor photodetector. On August 8, 1962, Biard and Pittman filed a patent titled "Semiconductor Radiant Diode" based on their findings, which described a zinc-diffused p–n junction LED with a spaced cathode contact to allow for efficient emission of infrared light under forward bias . After establishing the priority of their work based on engineering notebooks predating submissions from G.E. Labs, RCA Research Labs, IBM Research Labs, Bell Labs , and Lincoln Lab at MIT ,

376-657: A current source of a battery or a pulse generator and with a comparison to a variant, pure, crystal in 1953. Rubin Braunstein of the Radio Corporation of America reported on infrared emission from gallium arsenide (GaAs) and other semiconductor alloys in 1955. Braunstein observed infrared emission generated by simple diode structures using gallium antimonide (GaSb), GaAs, indium phosphide (InP), and silicon-germanium (SiGe) alloys at room temperature and at 77  kelvins . In 1957, Braunstein further demonstrated that

470-554: A glass window or lens to let the light out. Modern indicator LEDs are packed in transparent molded plastic cases, tubular or rectangular in shape, and often tinted to match the device color. Infrared devices may be dyed, to block visible light. More complex packages have been adapted for efficient heat dissipation in high-power LEDs . Surface-mounted LEDs further reduce the package size. LEDs intended for use with fiber optics cables may be provided with an optical connector. The first blue -violet LED, using magnesium-doped gallium nitride

564-522: A high proportion of straight drama, Shakespeare , other classic plays and premieres of new plays by leading playwrights—for example David Hare 's play Pravda starring Anthony Hopkins which was described by The Telegraph as "one of the biggest hits in the history of the National Theatre." Successful productions from the non-commercial theatres sometimes transfer to one of the commercial West End houses for an extended run. The Royal Opera House

658-568: A longer lifetime, improved physical robustness, smaller sizes, and faster switching. In exchange for these generally favorable attributes, disadvantages of LEDs include electrical limitations to low voltage and generally to DC (not AC) power, the inability to provide steady illumination from a pulsing DC or an AC electrical supply source, and a lesser maximum operating temperature and storage temperature. LEDs are transducers of electricity into light. They operate in reverse of photodiodes , which convert light into electricity. Electroluminescence as

752-481: A loudspeaker. Intercepting the beam stopped the music. We had a great deal of fun playing with this setup." In September 1961, while working at Texas Instruments in Dallas , Texas , James R. Biard and Gary Pittman discovered near-infrared (900 nm) light emission from a tunnel diode they had constructed on a GaAs substrate. By October 1961, they had demonstrated efficient light emission and signal coupling between

846-557: A method for producing high-brightness blue LEDs using a new two-step process in 1991. In 2015, a US court ruled that three Taiwanese companies had infringed Moustakas's prior patent, and ordered them to pay licensing fees of not less than US$ 13 million. Two years later, in 1993, high-brightness blue LEDs were demonstrated by Shuji Nakamura of Nichia Corporation using a gallium nitride (GaN) growth process. These LEDs had efficiencies of 10%. In parallel, Isamu Akasaki and Hiroshi Amano of Nagoya University were working on developing

940-514: A phenomenon was discovered in 1907 by the English experimenter Henry Joseph Round of Marconi Labs , using a crystal of silicon carbide and a cat's-whisker detector . Russian inventor Oleg Losev reported the creation of the first LED in 1927. His research was distributed in Soviet, German and British scientific journals, but no practical use was made of the discovery for several decades, partly due to

1034-567: A phosphor-silicon mixture on the LED using techniques such as jet dispensing, and allowing the solvents to evaporate, the LEDs are often tested, and placed on tapes for SMT placement equipment for use in LED light bulb production. Some "remote phosphor" LED light bulbs use a single plastic cover with YAG phosphor for one or several blue LEDs, instead of using phosphor coatings on single-chip white LEDs. Ce:YAG phosphors and epoxy in LEDs can degrade with use, and

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1128-621: A record-breaking nine Olivier Awards in 2017. "Theatre is such an important part of British history and British culture" —Dame Helen Mirren after receiving the Evening Standard Award in 2013 for her performance as the Queen in The Audience . The following shows are confirmed as future West End productions. The theatre in which they will run is either not yet known or currently occupied by another show. The term "West End theatre"

1222-503: A red light-emitting diode. GaAsP was the basis for the first wave of commercial LEDs emitting visible light. It was mass produced by the Monsanto and Hewlett-Packard companies and used widely for displays in calculators and wrist watches. M. George Craford , a former graduate student of Holonyak, invented the first yellow LED and improved the brightness of red and red-orange LEDs by a factor of ten in 1972. In 1976, T. P. Pearsall designed

1316-605: Is Les Misérables , produced by Cameron Mackintosh , which has been running in London since October 1985. It overtook Andrew Lloyd Webber 's Cats , which closed in 2002 after running for 8,949 performances and 21 years, as the longest-running West End musical of all time on 9 October 2006. Other long-runners include Lloyd Webber's The Phantom of the Opera , Willy Russell 's Blood Brothers , and Abba jukebox musical Mamma Mia! which have also subsequently overtaken Cats . However,

1410-480: Is currently the home of the musical Wicked , which has played at the venue since 27 September 2006. The theatre was built by architect Lewis and William Edward Trent in 1929 for Provincial Cinematograph Theatres , a part of the Gaumont British chain. The theatre was built with two identical façades on Wilton and Vauxhall Bridge Roads. Construction is principal of concrete, with strong horizontal banding along

1504-550: Is difficult but desirable since it takes advantage of existing semiconductor manufacturing infrastructure. It allows for the wafer-level packaging of LED dies resulting in extremely small LED packages. GaN is often deposited using metalorganic vapour-phase epitaxy (MOCVD), and it also uses lift-off . Even though white light can be created using individual red, green and blue LEDs, this results in poor color rendering , since only three narrow bands of wavelengths of light are being emitted. The attainment of high efficiency blue LEDs

1598-486: Is difficult on silicon , while others, like the University of Cambridge, choose a multi-layer structure, in order to reduce (crystal) lattice mismatch and different thermal expansion ratios, to avoid cracking of the LED chip at high temperatures (e.g. during manufacturing), reduce heat generation and increase luminous efficiency. Sapphire substrate patterning can be carried out with nanoimprint lithography . GaN-on-Si

1692-754: Is generally used to refer specifically to commercial productions in Theatreland. However, the leading non-commercial theatres in London enjoy great artistic prestige. These include the National Theatre , the Barbican Centre , Shakespeare's Globe (including the Sam Wanamaker Playhouse ), the Old Vic , Royal Court Theatre , Sadler's Wells Theatre , and the Regent's Park Open Air Theatre . These theatres stage

1786-618: Is mainstream professional theatre staged in the large theatres in and near the West End of London . Along with New York City 's Broadway theatre , West End theatre represents the highest level of commercial theatre in the English-speaking world . Seeing a West End show is a common tourist activity in London . Famous screen actors, British and international alike, frequently appear on the London stage. There are approximately 40 theatres in

1880-790: Is more apparent with higher concentrations of Ce:YAG in phosphor-silicone mixtures, because the Ce:YAG decomposes with use. The output of LEDs can shift to yellow over time due to degradation of the silicone. There are several variants of Ce:YAG, and manufacturers in many cases do not reveal the exact composition of their Ce:YAG offerings. Several other phosphors are available for phosphor-converted LEDs to produce several colors such as red, which uses nitrosilicate phosphors, and many other kinds of phosphor materials exist for LEDs such as phosphors based on oxides, oxynitrides, oxyhalides, halides, nitrides, sulfides, quantum dots, and inorganic-organic hybrid semiconductors. A single LED can have several phosphors at

1974-599: Is perceived as white light, with improved color rendering compared to wavelengths from the blue LED/YAG phosphor combination. The first white LEDs were expensive and inefficient. The light output then increased exponentially . The latest research and development has been propagated by Japanese manufacturers such as Panasonic and Nichia , and by Korean and Chinese manufacturers such as Samsung , Solstice, Kingsun, Hoyol and others. This trend in increased output has been called Haitz's law after Roland Haitz. Light output and efficiency of blue and near-ultraviolet LEDs rose and

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2068-451: Is to use individual LEDs that emit three primary colors —red, green and blue—and then mix all the colors to form white light. The other is to use a phosphor material to convert monochromatic light from a blue or UV LED to broad-spectrum white light, similar to a fluorescent lamp . The yellow phosphor is cerium -doped YAG crystals suspended in the package or coated on the LED. This YAG phosphor causes white LEDs to appear yellow when off, and

2162-680: Is widely regarded as one of the greatest opera houses in the world, comparable with the Palais Garnier and La Scala . Commonly known simply as Covent Garden due to its location, it is home to the Royal Opera , Royal Ballet and a resident symphony orchestra, and hosts guest performances from other leading opera, ballet and performance companies from around the world. In 1735 its first season of operas, by George Frideric Handel , began and many of his English oratorios were specifically written for Covent Garden and had their premieres here. Likewise,

2256-557: The COVID-19 pandemic , all theatres in the West End were closed until further notice. Theatres in London were allowed to re-open (with social distancing) on 17 May 2021, with full capacity permitted from 19 July. Opening in October 2022, @sohoplace is the first new West End theatre in 50 years. The length of West End shows depends on ticket sales. The longest-running musical in West End history

2350-771: The Comedy Theatre opened as the Royal Comedy Theatre on Panton Street in Leicester Square . It abbreviated its name three years later. On 23 December 1886, Alice in Wonderland (the first major production of the Alice books ) debuted at the Prince of Wales Theatre . Its author Lewis Carroll was involved in the stage adaptation, and he attended a performance seven days later. The Palace Theatre opened in 1891. Opened in 1892,

2444-462: The Duke of York's Theatre debuted J. M. Barrie 's play, Peter Pan, or The Boy Who Wouldn't Grow Up , on 27 December 1904. One of the most popular playwrights in London in the 1890s, Oscar Wilde , premiered his second comedy, A Woman of No Importance , at Haymarket Theatre in 1893. The subject of widespread public and media interest, Lillie Langtry (an associate of Wilde) made her West End debut in

2538-575: The English Reformation . The first permanent public playhouse, known as The Theatre , was constructed in 1576 in Shoreditch by James Burbage . It was soon joined by The Curtain . Both are known to have been used by William Shakespeare 's company. In 1599, the timber from The Theatre was moved to Southwark , where it was used in building the Globe Theatre in a new theatre district formed beyond

2632-690: The London Coliseum is the resident home to the English National Opera . The theatre is also the London base for performances by the English National Ballet , who perform regular seasons throughout the year when not on tour. The Peacock Theatre is located on the edge of the Theatreland area. Now owned by the London School of Economics and Political Science , it is used in the evenings for dance performances by Sadler's Wells , who manage

2726-949: The Lyric Hammersmith , Theatre Royal Stratford East , Rose Theatre, Kingston , New Wimbledon Theatre , the Rudolph Steiner Theatre in Westminster , the Ashcroft Theatre in Croydon , Secombe Theatre in Sutton , the Churchill Theatre in Bromley and the Hackney Empire in Hackney . London theatres outside the West End also played an important role in the early history of drama schools . In 1833, actress Frances Maria Kelly managed

2820-911: The Nobel Prize in Physics in 2014 for "the invention of efficient blue light-emitting diodes, which has enabled bright and energy-saving white light sources." In 1995, Alberto Barbieri at the Cardiff University Laboratory (GB) investigated the efficiency and reliability of high-brightness LEDs and demonstrated a "transparent contact" LED using indium tin oxide (ITO) on (AlGaInP/GaAs). In 2001 and 2002, processes for growing gallium nitride (GaN) LEDs on silicon were successfully demonstrated. In January 2012, Osram demonstrated high-power InGaN LEDs grown on silicon substrates commercially, and GaN-on-silicon LEDs are in production at Plessey Semiconductors . As of 2017, some manufacturers are using SiC as

2914-677: The Royal Strand Theatre in Westminster where she funded and operated a dramatic school, the earliest record of a drama school in England. In 1840 she financed the Royalty Theatre in Soho which opened as Miss Kelly's Theatre and Dramatic School. There are a number of annual awards for outstanding achievements in London theatre: LED Appearing as practical electronic components in 1962,

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3008-521: The Savoy Theatre in The Strand, built by Richard D'Oyly Carte specifically to showcase the comic operas of Gilbert and Sullivan , opened in October (the first theatre and public building to be lit by electric lights, with The Times recording, "the success of the new mode of illumination was complete, and its importance for the development of scenic art can scarcely be overrated"), and five days later

3102-544: The U.S. patent office issued the two inventors the patent for the GaAs infrared light-emitting diode (U.S. Patent US3293513 ), the first practical LED. Immediately after filing the patent, Texas Instruments (TI) began a project to manufacture infrared diodes. In October 1962, TI announced the first commercial LED product (the SNX-100), which employed a pure GaAs crystal to emit an 890 nm light output. In October 1963, TI announced

3196-457: The human eye as a pure ( saturated ) color. Also unlike most lasers, its radiation is not spatially coherent , so it cannot approach the very high intensity characteristic of lasers . By selection of different semiconductor materials , single-color LEDs can be made that emit light in a narrow band of wavelengths from near-infrared through the visible spectrum and into the ultraviolet range. The required operating voltages of LEDs increase as

3290-451: The 3-subpixel model for digital displays. The technology uses a gallium nitride semiconductor that emits light of different frequencies modulated by voltage changes. A prototype display achieved a resolution of 6,800 PPI or 3k x 1.5k pixels. In a light-emitting diode, the recombination of electrons and electron holes in a semiconductor produces light (be it infrared, visible or UV), a process called " electroluminescence ". The wavelength of

3384-635: The Apollo Victoria Theatre with a Shirley Bassey concert. Musicals, including The Sound of Music , Camelot and Fiddler on the Roof played at the theatre in the early 1980s. In 1984, the interior was extensively modified by the introduction of a 'race track' that ran through the audience, for the show Starlight Express with performers on roller skates. The show premièred on 27 March, composed by Andrew Lloyd Webber and directed by Trevor Nunn and ran for 7,406 performances, over 18 years. With

3478-626: The Patent Acts, as it was accompanied by music. Initially, these entertainments were presented in large halls, attached to public houses , but purpose-built theatres began to appear in the East End , such as the Pavilion Theatre in Whitechapel . The comic theatrical genre the harlequinade was also popular among London audiences. Its most famous performer, Joseph Grimaldi , best known for developing

3572-556: The Restoration (1660), Puritan legislation was declared null and void, and theatre (among other arts) exploded. Two companies were licensed to perform, the Duke's Company and the King's Company . Performances were held in converted buildings, such as Lisle's Tennis Court . The first West End theatre, known as Theatre Royal in Bridges Street, was designed by Thomas Killigrew and built on

3666-690: The Second World War, including John Gielgud , Alec Guinness , Vivien Leigh and Rex Harrison ; the latter's performance in Terence Rattigan 's 1936 comedy French Without Tears at the Criterion Theatre established him a leading light comedian. During the 1950s and 1960s, many plays were produced in theatre clubs, to evade the censorship then exercised by the Lord Chamberlain's Office . The Theatres Act 1968 finally abolished censorship of

3760-508: The West End, with the Theatre Royal, Drury Lane , opened in May 1663, the oldest theatre in London. The Savoy Theatre —built as a showcase for the popular series of comic operas of Gilbert and Sullivan —was entirely lit by electricity in 1881. The Society of London Theatre (SOLT) announced that 2018 was a record year for the capital's theatre industry with attendances topping 15.5 million for

3854-473: The area proper; an example is The Apollo Victoria Theatre , in Westminster . Prominent theatre streets include Drury Lane , Shaftesbury Avenue and the Strand. The works staged are predominantly musicals, classic and modern straight plays , and comedy performances. Many theatres in the West End are of late Victorian or Edwardian construction and are privately owned. Many are architecturally impressive, and

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3948-797: The blending of the colors. Since LEDs have slightly different emission patterns, the color balance may change depending on the angle of view, even if the RGB sources are in a single package, so RGB diodes are seldom used to produce white lighting. Nonetheless, this method has many applications because of the flexibility of mixing different colors, and in principle, this mechanism also has higher quantum efficiency in producing white light. There are several types of multicolor white LEDs: di- , tri- , and tetrachromatic white LEDs. Several key factors that play among these different methods include color stability, color rendering capability, and luminous efficacy. Often, higher efficiency means lower color rendering, presenting

4042-527: The ceiling. The theatre had a 74 feet (22.6 m) by 24 feet (7.3 m) stage and was equipped with 10 dressing rooms and two suites for principals. The theatre was Grade II* listed on 28 June 1972. It’s fish themed The theatre opened as the New Victoria Cinema on 15 October 1930 with a film starring George Arlis in Old English , based on a stage play by John Galsworthy . It was equipped with

4136-1083: The cladding and quantum well layers for ultraviolet LEDs, but these devices have not yet reached the level of efficiency and technological maturity of InGaN/GaN blue/green devices. If unalloyed GaN is used in this case to form the active quantum well layers, the device emits near-ultraviolet light with a peak wavelength centred around 365 nm. Green LEDs manufactured from the InGaN/GaN system are far more efficient and brighter than green LEDs produced with non-nitride material systems, but practical devices still exhibit efficiency too low for high-brightness applications. With AlGaN and AlGaInN , even shorter wavelengths are achievable. Near-UV emitters at wavelengths around 360–395 nm are already cheap and often encountered, for example, as black light lamp replacements for inspection of anti- counterfeiting UV watermarks in documents and bank notes, and for UV curing . Substantially more expensive, shorter-wavelength diodes are commercially available for wavelengths down to 240 nm. As

4230-519: The comedy She Stoops to Conquer in 1881. In 1878, Ellen Terry joined Henry Irving 's company as his leading lady, and for more than the next two decades she was considered the leading Shakespearean and comic actress in Britain. Opened in 1903, the New Theatre debuted The Scarlet Pimpernel in 1905, a play that introduced a heroic figure with an alter ego into the public consciousness. The theatre

4324-702: The conditions for the performance of plays, and The Strand gained another venue when the Vaudeville opened on 16 April 1870. The next few decades saw the opening of many new theatres in the West End. The Adelphi hosted A Christmas Carol; or, Past, Present, and Future in 1844, a play adapted from the novella A Christmas Carol by Charles Dickens —who came to several stage rehearsals during which he made suggestions—with his book published weeks earlier in December 1843. The Criterion Theatre opened on Piccadilly Circus on 21 March 1874, and in 1881, two more houses appeared:

4418-498: The controls of the City corporation. Regarding theatre as sinful, these theatres were closed in 1642 due to the Puritans who would later influence the interregnum of 1649. On 24 January 1643, the actors protested against the ban by writing a pamphlet titled The Actors remonstrance or complaint for the silencing of their profession, and banishment from their severall play-houses . After

4512-417: The cost of reliable devices fell. This led to relatively high-power white-light LEDs for illumination, which are replacing incandescent and fluorescent lighting. Experimental white LEDs were demonstrated in 2014 to produce 303 lumens per watt of electricity (lm/W); some can last up to 100,000 hours. Commercially available LEDs have an efficiency of up to 223 lm/W as of 2018. A previous record of 135 lm/W

4606-1075: The earliest LEDs emitted low-intensity infrared (IR) light. Infrared LEDs are used in remote-control circuits, such as those used with a wide variety of consumer electronics. The first visible-light LEDs were of low intensity and limited to red. Early LEDs were often used as indicator lamps, replacing small incandescent bulbs , and in seven-segment displays . Later developments produced LEDs available in visible , ultraviolet (UV), and infrared wavelengths with high, low, or intermediate light output, for instance, white LEDs suitable for room and outdoor lighting. LEDs have also given rise to new types of displays and sensors, while their high switching rates are useful in advanced communications technology with applications as diverse as aviation lighting , fairy lights , strip lights , automotive headlamps , advertising, general lighting , traffic signals , camera flashes, lighted wallpaper , horticultural grow lights , and medical devices. LEDs have many advantages over incandescent light sources, including lower power consumption,

4700-539: The emitted wavelengths become shorter (higher energy, red to blue), because of their increasing semiconductor band gap. Blue LEDs have an active region consisting of one or more InGaN quantum wells sandwiched between thicker layers of GaN, called cladding layers. By varying the relative In/Ga fraction in the InGaN quantum wells, the light emission can in theory be varied from violet to amber. Aluminium gallium nitride (AlGaN) of varying Al/Ga fraction can be used to manufacture

4794-449: The exterior sides of the auditorium. By contrast, the entrances feature a cantilevered canopy and are framed by vertical channelling, with two black marble columns rising to the roof line. The entrance is simple, making use of chrome trimmings, this leads to a nautical themed interior in the original Art Deco style that makes extensive use of concealed lighting, decorated with scallop shells and columns that burst into sculptured fountains at

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4888-491: The field of luminescence with research on radium . Hungarian Zoltán Bay together with György Szigeti patenting a lighting device in Hungary in 1939 based on silicon carbide, with an option on boron carbide, that emitted white, yellowish white, or greenish white depending on impurities present. Kurt Lehovec , Carl Accardo, and Edward Jamgochian explained these first LEDs in 1951 using an apparatus employing SiC crystals with

4982-602: The first commercial hemispherical LED, the SNX-110. In the 1960s, several laboratories focused on LEDs that would emit visible light. A particularly important device was demonstrated by Nick Holonyak on October 9, 1962, while he was working for General Electric in Syracuse, New York . The device used the semiconducting alloy gallium phosphide arsenide (GaAsP). It was the first semiconductor laser to emit visible light, albeit at low temperatures. At room temperature it still functioned as

5076-518: The first commercially available blue LED, based on the indirect bandgap semiconductor, silicon carbide (SiC). SiC LEDs had very low efficiency, no more than about 0.03%, but did emit in the blue portion of the visible light spectrum. In the late 1980s, key breakthroughs in GaN epitaxial growth and p-type doping ushered in the modern era of GaN-based optoelectronic devices. Building upon this foundation, Theodore Moustakas at Boston University patented

5170-721: The first high-brightness, high-efficiency LEDs for optical fiber telecommunications by inventing new semiconductor materials specifically adapted to optical fiber transmission wavelengths. Until 1968, visible and infrared LEDs were extremely costly, on the order of US$ 200 per unit, and so had little practical use. The first commercial visible-wavelength LEDs used GaAsP semiconductors and were commonly used as replacements for incandescent and neon indicator lamps , and in seven-segment displays , first in expensive equipment such as laboratory and electronics test equipment, then later in such appliances as calculators, TVs, radios, telephones, as well as watches. The Hewlett-Packard company (HP)

5264-579: The first time since the organisation began collecting audience data in 1986. Box office revenues exceeded £765 million. While attendance in 2019 was down 1.4% compared to the previous year, box office revenues reached a record £799 million. The majority of West End theatres are owned by the ATG Entertainment , Delfont Mackintosh Theatres , Nimax Theatres , LW Theatres , and the Nederlander Organization . Theatre in London flourished after

5358-407: The important GaN deposition on sapphire substrates and the demonstration of p-type doping of GaN. This new development revolutionized LED lighting, making high-power blue light sources practical, leading to the development of technologies like Blu-ray . Nakamura was awarded the 2006 Millennium Technology Prize for his invention. Nakamura, Hiroshi Amano , and Isamu Akasaki were awarded

5452-489: The largest and best maintained feature grand neo-classical, Romanesque, or Victorian façades and luxurious, detailed interior design and decoration. However, owing to the age of the buildings, leg room is often cramped, and audience facilities such as bars and toilets are often much smaller than in modern theatres. The protected status of the buildings and their confined urban locations, combined with financial constraints, make it very difficult to make substantial improvements to

5546-529: The level of comfort offered. In 2003, the Theatres Trust estimated that an investment of £250 million over the following 15 years was required for modernisation, and stated that 60% of theatres had seats from which the stage was not fully visible. The theatre owners unsuccessfully requested tax concessions to help them meet the costs. Starting in 2004, there were several incidents of falling plasterwork, or performances being cancelled because of urgent building repairs being required. These events culminated in

5640-417: The light depends on the energy band gap of the semiconductors used. Since these materials have a high index of refraction, design features of the devices such as special optical coatings and die shape are required to efficiently emit light. Unlike a laser , the light emitted from an LED is neither spectrally coherent nor even highly monochromatic . Its spectrum is sufficiently narrow that it appears to

5734-420: The light produced is engineered to suit the human eye. Because of metamerism , it is possible to have quite different spectra that appear white. The appearance of objects illuminated by that light may vary as the spectrum varies. This is the issue of color rendition, quite separate from color temperature. An orange or cyan object could appear with the wrong color and much darker as the LED or phosphor does not emit

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5828-429: The modern day white-face clown , made his stage debut at Drury Lane in 1780. The West End theatre district became established with the opening of many small theatres and halls, including the Adelphi in The Strand on 17 November 1806. South of the River Thames , the Old Vic , Waterloo Road , opened on 11 May 1818. The expansion of the West End theatre district gained pace with the Theatres Act 1843 , which relaxed

5922-448: The non-musical Agatha Christie play The Mousetrap is the longest-running production in the world, and has been performed continuously since 1952. Running since 2011, Matilda the Musical , an adaptation of Roald Dahl 's Matilda , won a then-record seven Olivier Awards in 2012. Running since 2016, Harry Potter and the Cursed Child , a two-part play written by Jack Thorne based on an original story by J. K. Rowling , won

6016-402: The partial collapse of the ceiling of the Apollo Theatre in December 2013. Of these earlier incidents, only one led to people being hurt, but at the Apollo 76 people needed medical treatment for their injuries. A number of West End theatres have undergone refurbishments, including the Victoria Palace Theatre following the run of Billy Elliot in 2016. The Dominion Theatre refurbishment

6110-418: The performances range from classic plays, to cabaret, to plays in the languages of London's ethnic minorities . The performers range from emerging young professionals to amateurs. Productions at the Donmar included the 1980 play Educating Rita which starred Julie Walters in the title role before she reprised the role in the 1983 film . There are many theatres located throughout Greater London , such as

6204-399: The phosphors, the Ce:YAG phosphor converts blue light to green and red (yellow) light, and the PFS phosphor converts blue light to red light. The color, emission spectrum or color temperature of white phosphor converted and other phosphor converted LEDs can be controlled by changing the concentration of several phosphors that form a phosphor blend used in an LED package. The 'whiteness' of

6298-599: The photosensitivity of microorganisms approximately matches the absorption spectrum of DNA , with a peak at about 260 nm, UV LED emitting at 250–270 nm are expected in prospective disinfection and sterilization devices. Recent research has shown that commercially available UVA LEDs (365 nm) are already effective disinfection and sterilization devices. UV-C wavelengths were obtained in laboratories using aluminium nitride (210 nm), boron nitride (215 nm) and diamond (235 nm). There are two primary ways of producing white light-emitting diodes. One

6392-400: The property, it operated as a "Musick House", with performances of opera; as it was not licensed for plays. In the West End, the Theatre Royal Haymarket opened on 29 December 1720 on a site slightly north of its current location, and the Royal Opera House opened in Covent Garden on 7 December 1732. John Gay 's ballad opera The Beggar's Opera ran for 62 performances in 1728, and held

6486-433: The record for London's longest run for nearly a century. It has been called "the most popular play of the eighteenth century." Another musical show, Tom and Jerry, or Life in London (1821), was the first London production to reach 100 consecutive performances . Tom and Jerry' s combination of a tour of London interspersed with song and dance, gave rise to numerous similar, loosely constructed entertainments, and "planted

6580-474: The removal of the 'tracks', the interior was extensively restored by architects Jaques Muir and Partners. This included the removal of 3,500 incandescent lamps that had become difficult to maintain and consumed a considerable amount of power. These were replaced by 88,000 low power LEDs specially designed for the theatre, creating the first auditorium completely lit in this way. Another Lloyd Webber production followed, Bombay Dreams premièred on 19 June 2002. It

6674-421: The rudimentary devices could be used for non-radio communication across a short distance. As noted by Kroemer Braunstein "…had set up a simple optical communications link: Music emerging from a record player was used via suitable electronics to modulate the forward current of a GaAs diode. The emitted light was detected by a PbS diode some distance away. This signal was fed into an audio amplifier and played back by

6768-480: The same time. Some LEDs use phosphors made of glass-ceramic or composite phosphor/glass materials. Alternatively, the LED chips themselves can be coated with a thin coating of phosphor-containing material, called a conformal coating. The temperature of the phosphor during operation and how it is applied limits the size of an LED die. Wafer-level packaged white LEDs allow for extremely small LEDs. In 2024, QPixel introduced as polychromatic LED that could replace

6862-414: The seeds for later musical comedy and revue". The Patent theatre companies retained their duopoly on drama well into the 19th century, and all other theatres could perform only musical entertainments. By the early 19th century, however, music hall entertainments became popular, and presenters found a loophole in the restrictions on non-patent theatres in the genre of melodrama . Melodrama did not break

6956-610: The site of the present Theatre Royal, Drury Lane . It opened on 7 May 1663 and was destroyed by a fire nine years later. It was replaced by a new structure designed by Christopher Wren and renamed the Theatre Royal, Drury Lane. One of the first actresses on the stage, Nell Gwyn became a star of restoration comedy. Outside the West End, Sadler's Wells Theatre opened in Islington on 3 June 1683. Taking its name from founder Richard Sadler and monastic springs that were discovered on

7050-408: The space between the crystals allow some blue light to pass through in LEDs with partial phosphor conversion. Alternatively, white LEDs may use other phosphors like manganese(IV)-doped potassium fluorosilicate (PFS) or other engineered phosphors. PFS assists in red light generation, and is used in conjunction with conventional Ce:YAG phosphor. In LEDs with PFS phosphor, some blue light passes through

7144-473: The stage in the United Kingdom. "Theatreland", London's main theatre district, contains approximately 40 venues and is located in and near the heart of the West End of London . It is traditionally defined by the Strand to the south, Oxford Street to the north, Regent Street to the west, and Kingsway to the east. However, a few other nearby theatres are also considered "West End" despite being outside

7238-547: The subsequent device Pankove and Miller built, the first actual gallium nitride light-emitting diode, emitted green light. In 1974 the U.S. Patent Office awarded Maruska, Rhines, and Stanford professor David Stevenson a patent for their work in 1972 (U.S. Patent US3819974 A ). Today, magnesium-doping of gallium nitride remains the basis for all commercial blue LEDs and laser diodes . In the early 1970s, these devices were too dim for practical use, and research into gallium nitride devices slowed. In August 1989, Cree introduced

7332-474: The substrate for LED production, but sapphire is more common, as it has the most similar properties to that of gallium nitride, reducing the need for patterning the sapphire wafer (patterned wafers are known as epi wafers). Samsung , the University of Cambridge , and Toshiba are performing research into GaN on Si LEDs. Toshiba has stopped research, possibly due to low yields. Some opt for epitaxy , which

7426-569: The team at Fairchild led by optoelectronics pioneer Thomas Brandt to achieve the needed cost reductions. LED producers have continued to use these methods as of about 2009. The early red LEDs were bright enough for use as indicators, as the light output was not enough to illuminate an area. Readouts in calculators were so small that plastic lenses were built over each digit to make them legible. Later, other colors became widely available and appeared in appliances and equipment. Early LEDs were packaged in metal cases similar to those of transistors, with

7520-631: The theatre on behalf of the school. There is a great number of stage productions in London outside the West End. Much of this is known as fringe theatre (referred to as Off West End ) which is the equivalent of off-Broadway and off-off-Broadway theatre in New York City. Among these are the Menier Chocolate Factory , Bush Theatre and the Donmar Warehouse . Fringe venues range from well-equipped small theatres to rooms above pubs, and

7614-416: The three London sites chosen to present a live relay of The Epsom Derby from the pre-war BBC experimental transmissions, utilising Baird equipment to project onto a screen 15 feet by 12 (4.6 by 3.7 m) in sepia. From September 1940 to May 1941, the theatre was closed due to World War II , but no serious damage was sustained and it reopened quickly. Plans were made for demolition in the 1950s, but it

7708-514: The venue on 27 September 2006 with a cast featuring Idina Menzel as Elphaba , Helen Dallimore as Glinda , Nigel Planer as The Wizard , Adam Garcia as Fiyero and Miriam Margolyes as Madame Morrible . On 27 September 2016, Wicked celebrated its tenth anniversary in the West End, with a curtain call reunion of former cast members. On April 24, 2024, Wicked became the 10th longest-running West End show in history with its 6,762nd performance. West End theatre West End theatre

7802-461: The very inefficient light-producing properties of silicon carbide, the semiconductor Losev used. In 1936, Georges Destriau observed that electroluminescence could be produced when zinc sulphide (ZnS) powder is suspended in an insulator and an alternating electrical field is applied to it. In his publications, Destriau often referred to luminescence as Losev-Light. Destriau worked in the laboratories of Madame Marie Curie , also an early pioneer in

7896-532: The wavelength it reflects. The best color rendition LEDs use a mix of phosphors, resulting in less efficiency and better color rendering. The first white light-emitting diodes (LEDs) were offered for sale in the autumn of 1996. Nichia made some of the first white LEDs which were based on blue LEDs with Ce:YAG phosphor. Ce:YAG is often grown using the Czochralski method . Mixing red, green, and blue sources to produce white light needs electronic circuits to control

7990-618: Was achieved by Nichia in 2010. Compared to incandescent bulbs, this is a huge increase in electrical efficiency, and even though LEDs are more expensive to purchase, overall lifetime cost is significantly cheaper than that of incandescent bulbs. The LED chip is encapsulated inside a small, plastic, white mold although sometimes an LED package can incorporate a reflector. It can be encapsulated using resin ( polyurethane -based), silicone, or epoxy containing (powdered) Cerium-doped YAG phosphor particles. The viscosity of phosphor-silicon mixtures must be carefully controlled. After application of

8084-507: Was completed in 2017 with the unveiling of a new double-sided LED screen, the largest and highest resolution projecting screen on the exterior of a West End theatre. In 2012, gross sales of £529,787,692 were up 0.27% and attendances also increased 0.56% to 13,992,773-year-on-year. In 2013, sales again rose this time by 11% to £585,506,455, with attendances rising to 14,587,276. This was despite slightly fewer performances occurring in 2013. On 16 March 2020, following government advice due to

8178-579: Was created by A. R. Rahman with lyrics by Don Black and was directed by Steven Pimlott , closing after 1,500 performances on 13 June 2004. This was followed by the return to the West End of the Bee Gee 's musical Saturday Night Fever on 6 July 2004, closing 22 October 2005 to tour. This was followed on 10 April 2006 by the jukebox musical Movin' Out , featuring the music of Billy Joel. This starred James Fox but ran for only two months. The Broadway musical Wicked received its London première at

8272-415: Was engaged in research and development (R&D) on practical LEDs between 1962 and 1968, by a research team under Howard C. Borden, Gerald P. Pighini at HP Associates and HP Labs . During this time HP collaborated with Monsanto Company on developing the first usable LED products. The first usable LED products were HP's LED display and Monsanto's LED indicator lamp , both launched in 1968. Monsanto

8366-433: Was made at Stanford University in 1972 by Herb Maruska and Wally Rhines , doctoral students in materials science and engineering. At the time Maruska was on leave from RCA Laboratories , where he collaborated with Jacques Pankove on related work. In 1971, the year after Maruska left for Stanford, his RCA colleagues Pankove and Ed Miller demonstrated the first blue electroluminescence from zinc-doped gallium nitride, though

8460-443: Was quickly followed by the development of the first white LED . In this device a Y 3 Al 5 O 12 :Ce (known as " YAG " or Ce:YAG phosphor) cerium -doped phosphor coating produces yellow light through fluorescence . The combination of that yellow with remaining blue light appears white to the eye. Using different phosphors produces green and red light through fluorescence. The resulting mixture of red, green and blue

8554-625: Was renamed the Noël Coward Theatre in 2006 after the playwright Noël Coward . Constructed in 1897, Her Majesty's Theatre hosted a number of premieres, including George Bernard Shaw 's Pygmalion in 1914. The theatre building boom continued until about the First World War . In 1930, Laurence Olivier had his first important West End success in Noël Coward's Private Lives . A number of other actors made their West End debut prior to

8648-745: Was saved and presented a mixture of ballet, live shows and films. The last films were shown in November 1975, a double bill of Peter Cushing in Legend of the Werewolf (1975) and Adrienne Corri in Vampire Circus (1972), though the theatre remained open until 1976, after which it closed for five years. It was a rock concert venue from 1976 until around 1980 with acts such as ELO, Cliff Richard , Peter Gabriel, Janis Ian and many others playing there. Led Zeppelin rehearsed there, on May Day , 1980. It reopened in 1981 as

8742-567: Was the first intelligent LED display, and was a revolution in digital display technology, replacing the Nixie tube and becoming the basis for later LED displays. In the 1970s, commercially successful LED devices at less than five cents each were produced by Fairchild Optoelectronics. These devices employed compound semiconductor chips fabricated with the planar process (developed by Jean Hoerni , ). The combination of planar processing for chip fabrication and innovative packaging methods enabled

8836-479: Was the first organization to mass-produce visible LEDs, using Gallium arsenide phosphide (GaAsP) in 1968 to produce red LEDs suitable for indicators. Monsanto had previously offered to supply HP with GaAsP, but HP decided to grow its own GaAsP. In February 1969, Hewlett-Packard introduced the HP Model 5082-7000 Numeric Indicator, the first LED device to use integrated circuit (integrated LED circuit ) technology. It

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