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John Dollond (30 November 1761) was an English optician, known for his successful optics business and his patenting and commercialization of Achromatic lens.
In 1758 he published an "Account of some experiments concerning the different refrangibility of light", describing the experiments that led him to the achievement with which his name is specially associated, the discovery of a means of constructing by the combination of crown and , reducing or eliminating chromatic aberration (distortion due to colour fringes). Leonhard Euler in 1747 had suggested that achromatism might be obtained by the combination of glass and water lenses. Relying on statements made by Sir Isaac Newton, Dollond first disputed this possibility ( Phil. Trans., 1753), but subsequently, after the Swedish physicist, Samuel Klingenstierna (1698–1765), had pointed out that Newton's law of dispersion did not harmonize with certain observed facts, Dollond began experiments to settle the question.
Early in 1757 Dollond succeeded in producing achromatic refraction by the aid of glass and water lenses, and a few months later he made a successful attempt to get the same result by a combination of glasses of different qualities (see History of telescopes). For this achievement the Royal Society awarded him the Copley Medal in 1758, and three years later elected him one of its fellows. Dollond also published two papers on apparatus for measuring small angles ( Phil. Trans., 1753, 1754).
In 1761, Dollond became the optician of King George III. He died of apoplexy on 30 November, of that year in London.
Dollond appears to have known of the prior work and refrained from enforcing his patent. After his death, his son, Peter, did take action to enforce the patent. A number of his competitors, including Bass, Benjamin Martin, Robert Rew and Jesse Ramsden, took action. Dollond's patent was upheld, as the court found that the patent was valid due to Dollond's exploitation of the invention while prior inventors did not. Several of the opticians were ruined by the expense of the legal proceedings and closed their shops as a result. The patent remained valid until it expired in 1772. Following the expiry of the patent, the price of achromatic doublets in England dropped by half.Ronald Pearsall, Collecting and Restoring Scientific Instruments, David and Charles, London 1974,
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