A seven segment display (sometimes written as 7-segment display) is a form of display that predates the now ubiquitous dot-matrix displays. Seven segment displays are commonly used in electronics as a method of displaying decimal numeric feedback on the internal operations of devices. A display device is a device for visual presentation of images (including text) acquired, stored, or transmitted in various forms. ... A dot matrix is an array of dots used to generate characters, symbols and images. ... Electronics is the study and use of electrical devices that operate by controlling the flow of electrons or other electrically charged particles in devices such as thermionic valves and semiconductors. ...

Concept and visual structure

A typical 7-segment LED display component, with decimal point

A seven segment display, as its name indicates, is composed of seven elements. Individually on or off, they can be combined to produce standardized representations of the arabic numerals. single unit seven segment display File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... single unit seven segment display File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... Arabic numerals (also called Hindu numerals or Hindu-Arabic numerals) are by far the most common form of symbolism used to represent numbers. ...

The seven segments are arranged as a rectangle of two vertical segments on each side with one horizontal segment on the top and bottom. Additionally, the seventh segment bisects the rectangle horizontally. There are also fourteen segment displays and sixteen segment displays (for full alphanumerics); however, these have mostly been replaced by dot-matrix displays. In geometry, a rectangle is a defined as a quadrilateral polygon in which all four angles are right angles. ... LCD fourteen segment display as seen on the HP-41 range of engineering calculators A fourteen segment display is an optoelectronic type of display based on 14 segments that can be turned on or off according to the graphic pattern to be produced. ... Segment layout, showing all 16 segments. ... Generally speaking, the term alphanumeric refers to anything that consists of only letters and numbers. ... A dot matrix is an array of dots used to generate characters, symbols and images. ...

Usually, but not always, the seven segments are arranged in an oblique, or italic, arrangement, which aids readability. Italic type is a form of type that slants slightly to the right and uses different glyph shapes, used to distinguish or otherwise set off certains words within text. ...

The segments of a 7-segment display are referred to by the letters A to G, as follows:

 AAAA F B F B F B GGGG E C E C E C DDDD DP 

where the optional DP decimal point (an "eighth segment") is used for the display of non-integer numbers. The decimal separator is used to mark the boundary between the integer and the fractional parts of a decimal numeral. ...

In addition to the ten numerals, seven segment displays can produce some of the latin letters: uppercase A, B, C, E, F, H, I, J, L, N, O, P, S, U, Y, Z and lowercase a, b, c, d, e, g, h, i, n, ñ, o, q, r, t, u. Some of these shapes, however, are visually highly ambiguous and rely on context and the experience of the reader to be properly understood and distinguished from each other. On a related note, school children and students have been known to produce letters and words from upside-down calculator displays. A basic arithmetic calculator. ...

Implementations

Most separate 7-segment displays use an array of light-emitting diodes (LEDs), though other types exist using alternative technologies such as cold cathode gas discharge, vacuum fluorescent, incandescent filament, liquid crystal display (LCD), etc. An alternative to the 7-segment display in the 1950s through the 1970s was the vacuum tube-like nixie tube. Integrated displays also exist, with multiple digits. Some of these integrated displays incorporate their own internal decoder, though most do not – each individual LED is brought out to a connecting pin. Various light-emitting diodes (5 mm reds, 3 mm greens and yellows) A light-emitting diode (LED) is a semiconductor device that emits incoherent monochromatic light when electrically biased in the forward direction. ... Diagram of a copper cathode The electrode of an electrochemical cell at which reduction occurs is referred to as the cathode (from the Greek word κάθοδος = going down). In an electrolytic cell the cathode is negatively charged and in a galvanic cell the cathode is positively charged. ... Reflective twisted nematic liquid crystal display. ... Millennia: 1st millennium - 2nd millennium - 3rd millennium Events and trends Technology United States tests the first fusion bomb. ... Events and trends Although in the United States and in many other Western societies the 1970s are often seen as a period of transition between the turbulent 1960s and the more conservative 1980s and 1990s, many of the trends that are associated widely with the Sixties, from the Sexual Revolution... A nixie tube is an electronic device for displaying numbers or other information, in the form of a glass tube containing multiple cathodes and a wire mesh anode, filled with neon and often a little mercury and/or argon at a small fraction of atmospheric pressure. ...

Seven segment displays can be found in patents as early as 1908 (United States patent 974943, for example), but did not achieve widespread use until the advent of LEDs and LCDs in the 1970s. They can even be used in unsophisticated displays like cardboard "For sale" signs, where the poster just paints on pre-printed segments to compose a product price or a telephone number. A patent is a set of exclusive rights granted by a government to an inventor or applicant for a limited amount of time (normally maximum 20 years from the filing date, depending on extension). ...

For many applications, dot-matrix LCDs have largely superseded LED displays, though even in LCDs 7-segment displays are very common. Unlike LEDs, the shapes of elements in an LCD panel are arbitrary since they are formed on the display by a kind of printing process. In contrast, the shapes of LED segments tend to be simple rectangles, reflecting the fact that they have to be physically moulded to shape, which makes it difficult to form more complex shapes. The low-power requirement of LCDs, along with the above features, make seven segment multiple-digit LCDs common in calculators. A basic arithmetic calculator. ...

See also

• Fourteen segment display