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WonderTechnology fact

In 1965 Eric Johnson, an engineer at Britain's Royal Radar Establishment in Malvern, described a screen that sensed the touch of a fingertip, intended for air traffic control. Screens that sense touch the same basic way, called capacitive, reached mobile phones only in 2007, more than 40 years later.

Electronics Letters, 1965

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The story behind the card

Johnson described the idea in a short article in the journal Electronics Letters in 1965, and in more detail in 1967. His screen had fine wires across its face. A finger touching them changed their capacitance, their ability to store an electric charge, and the electronics detected where. Today's phones use the same principle through a transparent conducting layer under the glass, which is why a thick glove usually does not work. In the early 1970s Frank Beck and Bent Stumpe built a transparent touchscreen for a control room at CERN. In the late 1970s the American company Elographics developed resistive screens, which sense two layers being pressed together, so any object can work them. IBM's Simon, sold from 1994, is widely seen as the first touchscreen phone. The LG Prada, released in May 2007, was the first phone with a capacitive screen, shortly before the first iPhone.

Türkçe oku
İngiliz mühendis Eric Johnson, 1965'te parmak dokunuşunu algılayan bir ekranı tarif etti. Malvern'deki Kraliyet Radar Kurumu'nda çalışan Johnson, ekranı hava trafik kontrolü için düşünmüştü. Aynı temel ilkeyle, yani kapasitif olarak çalışan ekranlar cep telefonlarına ancak 40 yılı aşkın bir süre sonra, 2007'de geldi.
Electronics Letters, 1965

Johnson fikrini 1965'te Electronics Letters dergisinde kısa bir makaleyle, 1967'de de fotoğraf ve çizimlerle daha ayrıntılı olarak anlattı. Ekranının önünde ince teller vardı. Parmak bu tellere değince tellerin kapasitansı, yani elektrik yükü depolayabilme özelliği değişiyor, devre de dokunulan yeri bu değişimden buluyordu. Bugünkü telefonlar aynı ilkeyi camın altındaki saydam, iletken bir katmanla uygular; kalın bir eldivenle ekranın çoğu zaman tepki vermemesinin nedeni budur. 1970'lerin başında Frank Beck ile Bent Stumpe, CERN'deki bir kontrol odası için saydam bir dokunmatik ekran yaptı. 1970'lerin sonunda Amerikan şirketi Elographics, üst üste duran iki katmanın birbirine bastırılmasını algılayan dirençli ekranları geliştirdi; bu ekranlar herhangi bir nesneyle kullanılabilir. 1994'te satışa çıkan IBM Simon, genellikle ilk dokunmatik ekranlı telefon kabul edilir. Kapasitif ekranlı ilk telefon ise ilk iPhone'dan kısa süre önce, Mayıs 2007'de çıkan LG Prada'ydı.

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