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Glass substrate with ITO electrodes. The shapes of these electrodes will determine the shapes that will appear when the LCD is switched ON. Vertical ridges etched on the surface are smooth.

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. Liquid crystals do not emit light directlybacklight or reflector to produce images in color or monochrome.seven-segment displays, as in a digital clock, are all good examples of devices with these displays. They use the same basic technology, except that arbitrary images are made from a matrix of small pixels, while other displays have larger elements. LCDs can either be normally on (positive) or off (negative), depending on the polarizer arrangement. For example, a character positive LCD with a backlight will have black lettering on a background that is the color of the backlight, and a character negative LCD will have a black background with the letters being of the same color as the backlight. Optical filters are added to white on blue LCDs to give them their characteristic appearance.

LCDs are used in a wide range of applications, including LCD televisions, computer monitors, instrument panels, aircraft cockpit displays, and indoor and outdoor signage. Small LCD screens are common in LCD projectors and portable consumer devices such as digital cameras, watches, digital clocks, calculators, and mobile telephones, including smartphones. LCD screens are also used on consumer electronics products such as DVD players, video game devices and clocks. LCD screens have replaced heavy, bulky cathode-ray tube (CRT) displays in nearly all applications. LCD screens are available in a wider range of screen sizes than CRT and plasma displays, with LCD screens available in sizes ranging from tiny digital watches to very large television receivers. LCDs are slowly being replaced by OLEDs, which can be easily made into different shapes, and have a lower response time, wider color gamut, virtually infinite color contrast and viewing angles, lower weight for a given display size and a slimmer profile (because OLEDs use a single glass or plastic panel whereas LCDs use two glass panels; the thickness of the panels increases with size but the increase is more noticeable on LCDs) and potentially lower power consumption (as the display is only "on" where needed and there is no backlight). OLEDs, however, are more expensive for a given display size due to the very expensive electroluminescent materials or phosphors that they use. Also due to the use of phosphors, OLEDs suffer from screen burn-in and there is currently no way to recycle OLED displays, whereas LCD panels can be recycled, although the technology required to recycle LCDs is not yet widespread. Attempts to maintain the competitiveness of LCDs are quantum dot displays, marketed as SUHD, QLED or Triluminos, which are displays with blue LED backlighting and a Quantum-dot enhancement film (QDEF) that converts part of the blue light into red and green, offering similar performance to an OLED display at a lower price, but the quantum dot layer that gives these displays their characteristics can not yet be recycled.

Since LCD screens do not use phosphors, they rarely suffer image burn-in when a static image is displayed on a screen for a long time, e.g., the table frame for an airline flight schedule on an indoor sign. LCDs are, however, susceptible to image persistence.battery-powered electronic equipment more efficiently than a CRT can be. By 2008, annual sales of televisions with LCD screens exceeded sales of CRT units worldwide, and the CRT became obsolete for most purposes.

Each pixel of an LCD typically consists of a layer of molecules aligned between two transparent electrodes, often made of Indium-Tin oxide (ITO) and two polarizing filters (parallel and perpendicular polarizers), the axes of transmission of which are (in most of the cases) perpendicular to each other. Without the liquid crystal between the polarizing filters, light passing through the first filter would be blocked by the second (crossed) polarizer. Before an electric field is applied, the orientation of the liquid-crystal molecules is determined by the alignment at the surfaces of electrodes. In a twisted nematic (TN) device, the surface alignment directions at the two electrodes are perpendicular to each other, and so the molecules arrange themselves in a helical structure, or twist. This induces the rotation of the polarization of the incident light, and the device appears gray. If the applied voltage is large enough, the liquid crystal molecules in the center of the layer are almost completely untwisted and the polarization of the incident light is not rotated as it passes through the liquid crystal layer. This light will then be mainly polarized perpendicular to the second filter, and thus be blocked and the pixel will appear black. By controlling the voltage applied across the liquid crystal layer in each pixel, light can be allowed to pass through in varying amounts thus constituting different levels of gray.

The chemical formula of the liquid crystals used in LCDs may vary. Formulas may be patented.Sharp Corporation. The patent that covered that specific mixture expired.

Most color LCD systems use the same technique, with color filters used to generate red, green, and blue subpixels. The LCD color filters are made with a photolithography process on large glass sheets that are later glued with other glass sheets containing a TFT array, spacers and liquid crystal, creating several color LCDs that are then cut from one another and laminated with polarizer sheets. Red, green, blue and black photoresists (resists) are used. All resists contain a finely ground powdered pigment, with particles being just 40 nanometers across. The black resist is the first to be applied; this will create a black grid (known in the industry as a black matrix) that will separate red, green and blue subpixels from one another, increasing contrast ratios and preventing light from leaking from one subpixel onto other surrounding subpixels.Super-twisted nematic LCD, where the variable twist between tighter-spaced plates causes a varying double refraction birefringence, thus changing the hue.

LCD in a Texas Instruments calculator with top polarizer removed from device and placed on top, such that the top and bottom polarizers are perpendicular. As a result, the colors are inverted.

The optical effect of a TN device in the voltage-on state is far less dependent on variations in the device thickness than that in the voltage-off state. Because of this, TN displays with low information content and no backlighting are usually operated between crossed polarizers such that they appear bright with no voltage (the eye is much more sensitive to variations in the dark state than the bright state). As most of 2010-era LCDs are used in television sets, monitors and smartphones, they have high-resolution matrix arrays of pixels to display arbitrary images using backlighting with a dark background. When no image is displayed, different arrangements are used. For this purpose, TN LCDs are operated between parallel polarizers, whereas IPS LCDs feature crossed polarizers. In many applications IPS LCDs have replaced TN LCDs, particularly in smartphones. Both the liquid crystal material and the alignment layer material contain ionic compounds. If an electric field of one particular polarity is applied for a long period of time, this ionic material is attracted to the surfaces and degrades the device performance. This is avoided either by applying an alternating current or by reversing the polarity of the electric field as the device is addressed (the response of the liquid crystal layer is identical, regardless of the polarity of the applied field).

Displays for a small number of individual digits or fixed symbols (as in digital watches and pocket calculators) can be implemented with independent electrodes for each segment.alphanumeric or variable graphics displays are usually implemented with pixels arranged as a matrix consisting of electrically connected rows on one side of the LC layer and columns on the other side, which makes it possible to address each pixel at the intersections. The general method of matrix addressing consists of sequentially addressing one side of the matrix, for example by selecting the rows one-by-one and applying the picture information on the other side at the columns row-by-row. For details on the various matrix addressing schemes see passive-matrix and active-matrix addressed LCDs.

LCDs, along with OLED displays, are manufactured in cleanrooms borrowing techniques from semiconductor manufacturing and using large sheets of glass whose size has increased over time. Several displays are manufactured at the same time, and then cut from the sheet of glass, also known as the mother glass or LCD glass substrate. The increase in size allows more displays or larger displays to be made, just like with increasing wafer sizes in semiconductor manufacturing. The glass sizes are as follows:

Until Gen 8, manufacturers would not agree on a single mother glass size and as a result, different manufacturers would use slightly different glass sizes for the same generation. Some manufacturers have adopted Gen 8.6 mother glass sheets which are only slightly larger than Gen 8.5, allowing for more 50 and 58 inch LCDs to be made per mother glass, specially 58 inch LCDs, in which case 6 can be produced on a Gen 8.6 mother glass vs only 3 on a Gen 8.5 mother glass, significantly reducing waste.AGC Inc., Corning Inc., and Nippon Electric Glass.

In 1922, Georges Friedel described the structure and properties of liquid crystals and classified them in three types (nematics, smectics and cholesterics). In 1927, Vsevolod Frederiks devised the electrically switched light valve, called the Fréedericksz transition, the essential effect of all LCD technology. In 1936, the Marconi Wireless Telegraph company patented the first practical application of the technology, "The Liquid Crystal Light Valve". In 1962, the first major English language publication Molecular Structure and Properties of Liquid Crystals was published by Dr. George W. Gray.RCA found that liquid crystals had some interesting electro-optic characteristics and he realized an electro-optical effect by generating stripe-patterns in a thin layer of liquid crystal material by the application of a voltage. This effect is based on an electro-hydrodynamic instability forming what are now called "Williams domains" inside the liquid crystal.

In the late 1960s, pioneering work on liquid crystals was undertaken by the UK"s Royal Radar Establishment at Malvern, England. The team at RRE supported ongoing work by George William Gray and his team at the University of Hull who ultimately discovered the cyanobiphenyl liquid crystals, which had correct stability and temperature properties for application in LCDs.

The idea of a TFT-based liquid-crystal display (LCD) was conceived by Bernard Lechner of RCA Laboratories in 1968.dynamic scattering mode (DSM) LCD that used standard discrete MOSFETs.

On December 4, 1970, the twisted nematic field effect (TN) in liquid crystals was filed for patent by Hoffmann-LaRoche in Switzerland, (Swiss patent No. 532 261) with Wolfgang Helfrich and Martin Schadt (then working for the Central Research Laboratories) listed as inventors.Brown, Boveri & Cie, its joint venture partner at that time, which produced TN displays for wristwatches and other applications during the 1970s for the international markets including the Japanese electronics industry, which soon produced the first digital quartz wristwatches with TN-LCDs and numerous other products. James Fergason, while working with Sardari Arora and Alfred Saupe at Kent State University Liquid Crystal Institute, filed an identical patent in the United States on April 22, 1971.ILIXCO (now LXD Incorporated), produced LCDs based on the TN-effect, which soon superseded the poor-quality DSM types due to improvements of lower operating voltages and lower power consumption. Tetsuro Hama and Izuhiko Nishimura of Seiko received a US patent dated February 1971, for an electronic wristwatch incorporating a TN-LCD.

In 1972, the concept of the active-matrix thin-film transistor (TFT) liquid-crystal display panel was prototyped in the United States by T. Peter Brody"s team at Westinghouse, in Pittsburgh, Pennsylvania.Westinghouse Research Laboratories demonstrated the first thin-film-transistor liquid-crystal display (TFT LCD).high-resolution and high-quality electronic visual display devices use TFT-based active matrix displays.active-matrix liquid-crystal display (AM LCD) in 1974, and then Brody coined the term "active matrix" in 1975.

In 1972 North American Rockwell Microelectronics Corp introduced the use of DSM LCDs for calculators for marketing by Lloyds Electronics Inc, though these required an internal light source for illumination.Sharp Corporation followed with DSM LCDs for pocket-sized calculators in 1973Seiko and its first 6-digit TN-LCD quartz wristwatch, and Casio"s "Casiotron". Color LCDs based on Guest-Host interaction were invented by a team at RCA in 1968.TFT LCDs similar to the prototypes developed by a Westinghouse team in 1972 were patented in 1976 by a team at Sharp consisting of Fumiaki Funada, Masataka Matsuura, and Tomio Wada,

In 1983, researchers at Brown, Boveri & Cie (BBC) Research Center, Switzerland, invented the passive matrix-addressed LCDs. H. Amstutz et al. were listed as inventors in the corresponding patent applications filed in Switzerland on July 7, 1983, and October 28, 1983. Patents were granted in Switzerland CH 665491, Europe EP 0131216,

The first color LCD televisions were developed as handheld televisions in Japan. In 1980, Hattori Seiko"s R&D group began development on color LCD pocket televisions.Seiko Epson released the first LCD television, the Epson TV Watch, a wristwatch equipped with a small active-matrix LCD television.dot matrix TN-LCD in 1983.Citizen Watch,TFT LCD.computer monitors and LCD televisions.3LCD projection technology in the 1980s, and licensed it for use in projectors in 1988.compact, full-color LCD projector.

In 1990, under different titles, inventors conceived electro optical effects as alternatives to twisted nematic field effect LCDs (TN- and STN- LCDs). One approach was to use interdigital electrodes on one glass substrate only to produce an electric field essentially parallel to the glass substrates.Germany by Guenter Baur et al. and patented in various countries.Hitachi work out various practical details of the IPS technology to interconnect the thin-film transistor array as a matrix and to avoid undesirable stray fields in between pixels.

Hitachi also improved the viewing angle dependence further by optimizing the shape of the electrodes (Super IPS). NEC and Hitachi become early manufacturers of active-matrix addressed LCDs based on the IPS technology. This is a milestone for implementing large-screen LCDs having acceptable visual performance for flat-panel computer monitors and television screens. In 1996, Samsung developed the optical patterning technique that enables multi-domain LCD. Multi-domain and In Plane Switching subsequently remain the dominant LCD designs through 2006.South Korea and Taiwan,

In 2007 the image quality of LCD televisions surpassed the image quality of cathode-ray-tube-based (CRT) TVs.LCD TVs were projected to account 50% of the 200 million TVs to be shipped globally in 2006, according to Displaybank.Toshiba announced 2560 × 1600 pixels on a 6.1-inch (155 mm) LCD panel, suitable for use in a tablet computer,transparent and flexible, but they cannot emit light without a backlight like OLED and microLED, which are other technologies that can also be made flexible and transparent.

In 2016, Panasonic developed IPS LCDs with a contrast ratio of 1,000,000:1, rivaling OLEDs. This technology was later put into mass production as dual layer, dual panel or LMCL (Light Modulating Cell Layer) LCDs. The technology uses 2 liquid crystal layers instead of one, and may be used along with a mini-LED backlight and quantum dot sheets.

Since LCDs produce no light of their own, they require external light to produce a visible image.backlight. Active-matrix LCDs are almost always backlit.Transflective LCDs combine the features of a backlit transmissive display and a reflective display.

CCFL: The LCD panel is lit either by two cold cathode fluorescent lamps placed at opposite edges of the display or an array of parallel CCFLs behind larger displays. A diffuser (made of PMMA acrylic plastic, also known as a wave or light guide/guiding plateinverter to convert whatever DC voltage the device uses (usually 5 or 12 V) to ≈1000 V needed to light a CCFL.

EL-WLED: The LCD panel is lit by a row of white LEDs placed at one or more edges of the screen. A light diffuser (light guide plate, LGP) is then used to spread the light evenly across the whole display, similarly to edge-lit CCFL LCD backlights. The diffuser is made out of either PMMA plastic or special glass, PMMA is used in most cases because it is rugged, while special glass is used when the thickness of the LCD is of primary concern, because it doesn"t expand as much when heated or exposed to moisture, which allows LCDs to be just 5mm thick. Quantum dots may be placed on top of the diffuser as a quantum dot enhancement film (QDEF, in which case they need a layer to be protected from heat and humidity) or on the color filter of the LCD, replacing the resists that are normally used.

WLED array: The LCD panel is lit by a full array of white LEDs placed behind a diffuser behind the panel. LCDs that use this implementation will usually have the ability to dim or completely turn off the LEDs in the dark areas of the image being displayed, effectively increasing the contrast ratio of the display. The precision with which this can be done will depend on the number of dimming zones of the display. The more dimming zones, the more precise the dimming, with less obvious blooming artifacts which are visible as dark grey patches surrounded by the unlit areas of the LCD. As of 2012, this design gets most of its use from upscale, larger-screen LCD televisions.

RGB-LED array: Similar to the WLED array, except the panel is lit by a full array of RGB LEDs. While displays lit with white LEDs usually have a poorer color gamut than CCFL lit displays, panels lit with RGB LEDs have very wide color gamuts. This implementation is most popular on professional graphics editing LCDs. As of 2012, LCDs in this category usually cost more than $1000. As of 2016 the cost of this category has drastically reduced and such LCD televisions obtained same price levels as the former 28" (71 cm) CRT based categories.

Monochrome LEDs: such as red, green, yellow or blue LEDs are used in the small passive monochrome LCDs typically used in clocks, watches and small appliances.

Today, most LCD screens are being designed with an LED backlight instead of the traditional CCFL backlight, while that backlight is dynamically controlled with the video information (dynamic backlight control). The combination with the dynamic backlight control, invented by Philips researchers Douglas Stanton, Martinus Stroomer and Adrianus de Vaan, simultaneously increases the dynamic range of the display system (also marketed as HDR, high dynamic range television or FLAD, full-area local area dimming).

The LCD backlight systems are made highly efficient by applying optical films such as prismatic structure (prism sheet) to gain the light into the desired viewer directions and reflective polarizing films that recycle the polarized light that was formerly absorbed by the first polarizer of the LCD (invented by Philips researchers Adrianus de Vaan and Paulus Schaareman),

Due to the LCD layer that generates the desired high resolution images at flashing video speeds using very low power electronics in combination with LED based backlight technologies, LCD technology has become the dominant display technology for products such as televisions, desktop monitors, notebooks, tablets, smartphones and mobile phones. Although competing OLED technology is pushed to the market, such OLED displays do not feature the HDR capabilities like LCDs in combination with 2D LED backlight technologies have, reason why the annual market of such LCD-based products is still growing faster (in volume) than OLED-based products while the efficiency of LCDs (and products like portable computers, mobile phones and televisions) may even be further improved by preventing the light to be absorbed in the colour filters of the LCD.

A pink elastomeric connector mating an LCD panel to circuit board traces, shown next to a centimeter-scale ruler. The conductive and insulating layers in the black stripe are very small.

A standard television receiver screen, a modern LCD panel, has over six million pixels, and they are all individually powered by a wire network embedded in the screen. The fine wires, or pathways, form a grid with vertical wires across the whole screen on one side of the screen and horizontal wires across the whole screen on the other side of the screen. To this grid each pixel has a positive connection on one side and a negative connection on the other side. So the total amount of wires needed for a 1080p display is 3 x 1920 going vertically and 1080 going horizontally for a total of 6840 wires horizontally and vertically. That"s three for red, green and blue and 1920 columns of pixels for each color for a total of 5760 wires going vertically and 1080 rows of wires going horizontally. For a panel that is 28.8 inches (73 centimeters) wide, that means a wire density of 200 wires per inch along the horizontal edge.

The LCD panel is powered by LCD drivers that are carefully matched up with the edge of the LCD panel at the factory level. The drivers may be installed using several methods, the most common of which are COG (Chip-On-Glass) and TAB (Tape-automated bonding) These same principles apply also for smartphone screens that are much smaller than TV screens.anisotropic conductive film or, for lower densities, elastomeric connectors.

Monochrome and later color passive-matrix LCDs were standard in most early laptops (although a few used plasma displaysGame Boyactive-matrix became standard on all laptops. The commercially unsuccessful Macintosh Portable (released in 1989) was one of the first to use an active-matrix display (though still monochrome). Passive-matrix LCDs are still used in the 2010s for applications less demanding than laptop computers and TVs, such as inexpensive calculators. In particular, these are used on portable devices where less information content needs to be displayed, lowest power consumption (no backlight) and low cost are desired or readability in direct sunlight is needed.

STN LCDs have to be continuously refreshed by alternating pulsed voltages of one polarity during one frame and pulses of opposite polarity during the next frame. Individual pixels are addressed by the corresponding row and column circuits. This type of display is called response times and poor contrast are typical of passive-matrix addressed LCDs with too many pixels and driven according to the "Alt & Pleshko" drive scheme. Welzen and de Vaan also invented a non RMS drive scheme enabling to drive STN displays with video rates and enabling to show smooth moving video images on an STN display.

Bistable LCDs do not require continuous refreshing. Rewriting is only required for picture information changes. In 1984 HA van Sprang and AJSM de Vaan invented an STN type display that could be operated in a bistable mode, enabling extremely high resolution images up to 4000 lines or more using only low voltages.

High-resolution color displays, such as modern LCD computer monitors and televisions, use an active-matrix structure. A matrix of thin-film transistors (TFTs) is added to the electrodes in contact with the LC layer. Each pixel has its own dedicated transistor, allowing each column line to access one pixel. When a row line is selected, all of the column lines are connected to a row of pixels and voltages corresponding to the picture information are driven onto all of the column lines. The row line is then deactivated and the next row line is selected. All of the row lines are selected in sequence during a refresh operation. Active-matrix addressed displays look brighter and sharper than passive-matrix addressed displays of the same size, and generally have quicker response times, producing much better images. Sharp produces bistable reflective LCDs with a 1-bit SRAM cell per pixel that only requires small amounts of power to maintain an image.

Segment LCDs can also have color by using Field Sequential Color (FSC LCD). This kind of displays have a high speed passive segment LCD panel with an RGB backlight. The backlight quickly changes color, making it appear white to the naked eye. The LCD panel is synchronized with the backlight. For example, to make a segment appear red, the segment is only turned ON when the backlight is red, and to make a segment appear magenta, the segment is turned ON when the backlight is blue, and it continues to be ON while the backlight becomes red, and it turns OFF when the backlight becomes green. To make a segment appear black, the segment is always turned ON. An FSC LCD divides a color image into 3 images (one Red, one Green and one Blue) and it displays them in order. Due to persistence of vision, the 3 monochromatic images appear as one color image. An FSC LCD needs an LCD panel with a refresh rate of 180 Hz, and the response time is reduced to just 5 milliseconds when compared with normal STN LCD panels which have a response time of 16 milliseconds.

Samsung introduced UFB (Ultra Fine & Bright) displays back in 2002, utilized the super-birefringent effect. It has the luminance, color gamut, and most of the contrast of a TFT-LCD, but only consumes as much power as an STN display, according to Samsung. It was being used in a variety of Samsung cellular-telephone models produced until late 2006, when Samsung stopped producing UFB displays. UFB displays were also used in certain models of LG mobile phones.

In-plane switching is an LCD technology that aligns the liquid crystals in a plane parallel to the glass substrates. In this method, the electrical field is applied through opposite electrodes on the same glass substrate, so that the liquid crystals can be reoriented (switched) essentially in the same plane, although fringe fields inhibit a homogeneous reorientation. This requires two transistors for each pixel instead of the single transistor needed for a standard thin-film transistor (TFT) display. The IPS technology is used in everything from televisions, computer monitors, and even wearable devices, especially almost all LCD smartphone panels are IPS/FFS mode. IPS displays belong to the LCD panel family screen types. The other two types are VA and TN. Before LG Enhanced IPS was introduced in 2001 by Hitachi as 17" monitor in Market, the additional transistors resulted in blocking more transmission area, thus requiring a brighter backlight and consuming more power, making this type of display less desirable for notebook computers. Panasonic Himeji G8.5 was using an enhanced version of IPS, also LGD in Korea, then currently the world biggest LCD panel manufacture BOE in China is also IPS/FFS mode TV panel.

In 2015 LG Display announced the implementation of a new technology called M+ which is the addition of white subpixel along with the regular RGB dots in their IPS panel technology.

In 2011, LG claimed the smartphone LG Optimus Black (IPS LCD (LCD NOVA)) has the brightness up to 700 nits, while the competitor has only IPS LCD with 518 nits and double an active-matrix OLED (AMOLED) display with 305 nits. LG also claimed the NOVA display to be 50 percent more efficient than regular LCDs and to consume only 50 percent of the power of AMOLED displays when producing white on screen.

This pixel-layout is found in S-IPS LCDs. A chevron shape is used to widen the viewing cone (range of viewing directions with good contrast and low color shift).

Vertical-alignment displays are a form of LCDs in which the liquid crystals naturally align vertically to the glass substrates. When no voltage is applied, the liquid crystals remain perpendicular to the substrate, creating a black display between crossed polarizers. When voltage is applied, the liquid crystals shift to a tilted position, allowing light to pass through and create a gray-scale display depending on the amount of tilt generated by the electric field. It has a deeper-black background, a higher contrast ratio, a wider viewing angle, and better image quality at extreme temperatures than traditional twisted-nematic displays.

Blue phase mode LCDs have been shown as engineering samples early in 2008, but they are not in mass-production. The physics of blue phase mode LCDs suggest that very short switching times (≈1 ms) can be achieved, so time sequential color control can possibly be realized and expensive color filters would be obsolete.

Some LCD panels have defective transistors, causing permanently lit or unlit pixels which are commonly referred to as stuck pixels or dead pixels respectively. Unlike integrated circuits (ICs), LCD panels with a few defective transistors are usually still usable. Manufacturers" policies for the acceptable number of defective pixels vary greatly. At one point, Samsung held a zero-tolerance policy for LCD monitors sold in Korea.ISO 13406-2 standard.

Dead pixel policies are often hotly debated between manufacturers and customers. To regulate the acceptability of defects and to protect the end user, ISO released the ISO 13406-2 standard,ISO 9241, specifically ISO-9241-302, 303, 305, 307:2008 pixel defects. However, not every LCD manufacturer conforms to the ISO standard and the ISO standard is quite often interpreted in different ways. LCD panels are more likely to have defects than most ICs due to their larger size. For example, a 300 mm SVGA LCD has 8 defects and a 150 mm wafer has only 3 defects. However, 134 of the 137 dies on the wafer will be acceptable, whereas rejection of the whole LCD panel would be a 0% yield. In recent years, quality control has been improved. An SVGA LCD panel with 4 defective pixels is usually considered defective and customers can request an exchange for a new one.

Some manufacturers, notably in South Korea where some of the largest LCD panel manufacturers, such as LG, are located, now have a zero-defective-pixel guarantee, which is an extra screening process which can then determine "A"- and "B"-grade panels.clouding (or less commonly mura), which describes the uneven patches of changes in luminance. It is most visible in dark or black areas of displayed scenes.

The zenithal bistable device (ZBD), developed by Qinetiq (formerly DERA), can retain an image without power. The crystals may exist in one of two stable orientations ("black" and "white") and power is only required to change the image. ZBD Displays is a spin-off company from QinetiQ who manufactured both grayscale and color ZBD devices. Kent Displays has also developed a "no-power" display that uses polymer stabilized cholesteric liquid crystal (ChLCD). In 2009 Kent demonstrated the use of a ChLCD to cover the entire surface of a mobile phone, allowing it to change colors, and keep that color even when power is removed.

In 2004, researchers at the University of Oxford demonstrated two new types of zero-power bistable LCDs based on Zenithal bistable techniques.e.g., BiNem technology, are based mainly on the surface properties and need specific weak anchoring materials.

Resolution The resolution of an LCD is expressed by the number of columns and rows of pixels (e.g., 1024×768). Each pixel is usually composed 3 sub-pixels, a red, a green, and a blue one. This had been one of the few features of LCD performance that remained uniform among different designs. However, there are newer designs that share sub-pixels among pixels and add Quattron which attempt to efficiently increase the perceived resolution of a display without increasing the actual resolution, to mixed results.

Spatial performance: For a computer monitor or some other display that is being viewed from a very close distance, resolution is often expressed in terms of dot pitch or pixels per inch, which is consistent with the printing industry. Display density varies per application, with televisions generally having a low density for long-distance viewing and portable devices having a high density for close-range detail. The Viewing Angle of an LCD may be important depending on the display and its usage, the limitations of certain display technologies mean the display only displays accurately at certain angles.

Temporal performance: the temporal resolution of an LCD is how well it can display changing images, or the accuracy and the number of times per second the display draws the data it is being given. LCD pixels do not flash on/off between frames, so LCD monitors exhibit no refresh-induced flicker no matter how low the refresh rate.

Brightness and contrast ratio: Contrast ratio is the ratio of the brightness of a full-on pixel to a full-off pixel. The LCD itself is only a light valve and does not generate light; the light comes from a backlight that is either fluorescent or a set of LEDs. Brightness is usually stated as the maximum light output of the LCD, which can vary greatly based on the transparency of the LCD and the brightness of the backlight. Brighter backlight allows stronger contrast and higher dynamic range (HDR displays are graded in peak luminance), but there is always a trade-off between brightness and power consumption.

Low power consumption. Depending on the set display brightness and content being displayed, the older CCFT backlit models typically use less than half of the power a CRT monitor of the same size viewing area would use, and the modern LED backlit models typically use 10–25% of the power a CRT monitor would use.

Usually no refresh-rate flicker, because the LCD pixels hold their state between refreshes (which are usually done at 200 Hz or faster, regardless of the input refresh rate).

No theoretical resolution limit. When multiple LCD panels are used together to create a single canvas, each additional panel increases the total resolution of the display, which is commonly called stacked resolution.

As an inherently digital device, the LCD can natively display digital data from a DVI or HDMI connection without requiring conversion to analog. Some LCD panels have native fiber optic inputs in addition to DVI and HDMI.

As of 2012, most implementations of LCD backlighting use pulse-width modulation (PWM) to dim the display,CRT monitor at 85 Hz refresh rate would (this is because the entire screen is strobing on and off rather than a CRT"s phosphor sustained dot which continually scans across the display, leaving some part of the display always lit), causing severe eye-strain for some people.LED-backlit monitors, because the LEDs switch on and off faster than a CCFL lamp.

Fixed bit depth (also called color depth). Many cheaper LCDs are only able to display 262144 (218) colors. 8-bit S-IPS panels can display 16 million (224) colors and have significantly better black level, but are expensive and have slower response time.

Input lag, because the LCD"s A/D converter waits for each frame to be completely been output before drawing it to the LCD panel. Many LCD monitors do post-processing before displaying the image in an attempt to compensate for poor color fidelity, which adds an additional lag. Further, a video scaler must be used when displaying non-native resolutions, which adds yet more time lag. Scaling and post processing are usually done in a single chip on modern monitors, but each function that chip performs adds some delay. Some displays have a video gaming mode which disables all or most processing to reduce perceivable input lag.

Loss of brightness and much slower response times in low temperature environments. In sub-zero environments, LCD screens may cease to function without the use of supplemental heating.

The production of LCD screens uses nitrogen trifluoride (NF3) as an etching fluid during the production of the thin-film components. NF3 is a potent greenhouse gas, and its relatively long half-life may make it a potentially harmful contributor to global warming. A report in Geophysical Research Letters suggested that its effects were theoretically much greater than better-known sources of greenhouse gasses like carbon dioxide. As NF3 was not in widespread use at the time, it was not made part of the Kyoto Protocols and has been deemed "the missing greenhouse gas".

Kawamoto, H. (2012). "The Inventors of TFT Active-Matrix LCD Receive the 2011 IEEE Nishizawa Medal". Journal of Display Technology. 8 (1): 3–4. Bibcode:2012JDisT...8....3K. doi:10.1109/JDT.2011.2177740. ISSN 1551-319X.

Brody, T. Peter; Asars, J. A.; Dixon, G. D. (November 1973). "A 6 × 6 inch 20 lines-per-inch liquid-crystal display panel". 20 (11): 995–1001. Bibcode:1973ITED...20..995B. doi:10.1109/T-ED.1973.17780. ISSN 0018-9383.

Explanation of CCFL backlighting details, "Design News — Features — How to Backlight an LCD" Archived January 2, 2014, at the Wayback Machine, Randy Frank, Retrieved January 2013.

Energy Efficiency Success Story: TV Energy Consumption Shrinks as Screen Size and Performance Grow, Finds New CTA Study; Consumer Technology Association; press release 12 July 2017; https://cta.tech/News/Press-Releases/2017/July/Energy-Efficiency-Success-Story-TV-Energy-Consump.aspx Archived November 4, 2017, at the Wayback Machine

LCD Television Power Draw Trends from 2003 to 2015; B. Urban and K. Roth; Fraunhofer USA Center for Sustainable Energy Systems; Final Report to the Consumer Technology Association; May 2017; http://www.cta.tech/cta/media/policyImages/policyPDFs/Fraunhofer-LCD-TV-Power-Draw-Trends-FINAL.pdf Archived August 1, 2017, at the Wayback Machine

New Cholesteric Colour Filters for Reflective LCDs; C. Doornkamp; R. T. Wegh; J. Lub; SID Symposium Digest of Technical Papers; Volume 32, Issue 1 June 2001; Pages 456–459; http://onlinelibrary.wiley.com/doi/10.1889/1.1831895/full

K. H. Lee; H. Y. Kim; K. H. Park; S. J. Jang; I. C. Park & J. Y. Lee (June 2006). "A Novel Outdoor Readability of Portable TFT-LCD with AFFS Technology". SID Symposium Digest of Technical Papers. 37 (1): 1079–1082. doi:10.1889/1.2433159. S2CID 129569963.

Jack H. Park (January 15, 2015). "Cut and Run: Taiwan-controlled LCD Panel Maker in Danger of Shutdown without Further Investment". www.businesskorea.co.kr. Archived from the original on May 12, 2015. Retrieved April 23, 2015.

NXP Semiconductors (October 21, 2011). "UM10764 Vertical Alignment (VA) displays and NXP LCD drivers" (PDF). Archived from the original (PDF) on March 14, 2014. Retrieved September 4, 2014.

"Samsung to Offer "Zero-PIXEL-DEFECT" Warranty for LCD Monitors". Forbes. December 30, 2004. Archived from the original on August 20, 2007. Retrieved September 3, 2007.

"Display (LCD) replacement for defective pixels – ThinkPad". Lenovo. June 25, 2007. Archived from the original on December 31, 2006. Retrieved July 13, 2007.

Explanation of why pulse width modulated backlighting is used, and its side-effects, "Pulse Width Modulation on LCD monitors", TFT Central. Retrieved June 2012.

An enlightened user requests Dell to improve their LCD backlights, "Request to Dell for higher backlight PWM frequency" Archived December 13, 2012, at the Wayback Machine, Dell Support Community. Retrieved June 2012.

Oleg Artamonov (January 23, 2007). "Contemporary LCD Monitor Parameters: Objective and Subjective Analysis". X-bit labs. Archived from the original on May 16, 2008. Retrieved May 17, 2008.

a line of extreme and ultra-narrow bezel LCD displays that provides a video wall solution for demanding requirements of 24x7 mission-critical applications and high ambient light environments

LCD Calendar with Calculator (RP207) --Automatic date turn over --Calendar and time display --Monthly calendar query --A set of alarm --8 digit calculator with key tone

Hewlett Packard 35, (1972-1975) this historic model was the first scientific pocket calculator and signaled HP as an innovator in calculator design. It sold for $395, over $1,800 in 2006 dollars. Like many HP calculators the HP 35 uses Reverse Polish Notation (RPN). With RPN you first enter the number and then tell the calculator what to do with it. According to an HP article on RPN, RPN has several advantages over typical algebraic entry including showing intermediate answers and using fewer keystrokes. HP says it"s easy, and now even has a virtual RPN calculator at the above link to try it out. Made in USA. Mine appears to be the third of four versions of the HP 35. Over 300,000 were sold, vastly exceeding expectations. The HP 35 signaled the death of the slide rule. The TI 50 eventually competed with it with a significantly lower price but without the RPN preferred by many. Mine was purchased for $45 with $5 shipping in February 2006 on eBay. That"s expensive, but HP calcualtors, both used and new, tend to be expensive. The description said it works, but it did not come with batteries or a charger to test it. I had an HP charger (82026A) from a garage sale ($1) that I thought would work, but it has a slightly different two hole connection while the HP 35 calculator has three pins. After some experimenting I got it to work with three 1.2 volt NI-MH rechargeable batteries taped together with Aluminum foil to join negative and positive terminals and speaker wire to hook the battery terminials to the calculator terminals (upper one went to negative battery terminal). This closely approximates the 3.5 volts of the original battery pack. (I did not do this for long and I don"t know if this can cause injury or damage, so don"t necessarily do what I did!) With this arrangement you, of course, must charge the batteries outside the calculator in an appropriate battery charger. There is excellent information on the HP 35 at several sites including HP site, Museum of HP Calculators, Museum of HP Calculators Simulation, Wikipedia, Vintage Calculators, Making New Battery Packs for the HP 35 Calculator, Educalc.net (exploded view), HP Calculator History - Trascendental Functions, Datamath.org - Internal View HP 35.

Hewlett Packard 67, (1976-1982) The HP 67 is a programable scientific calculator that was introduced around the height of the calculator boom of the 1970s and at the beginning of the personal computer revolution. (The Altair 8088 computer was introduced in 1975 and the Apple 1 computer was introduced in July 1976.) The similar HP 97 was a desktop version with an integrated printer. The HP 67 sold for $450 in 1976, or about $2075 in 2020 dollars. That"s a lot of money but having that computing power in your pocket was well worth it to engineers and scientists. The HP 67 was the successor to the HP 65 introduced in 1974 with a suggested retail price of $795, or about $4,400 in 2020 dollars! The HP 65 was the first hand-held programmable calculator. At the time, Apple co-founder, Steve Wozniak, was a scientific calculator designer at Hewlett Packard and sold his HP 65 in 1976 for $500 to help finance the start of Apple Computers. In 2013 Wozniak stated, "The next month HP was going to introduce the HP-67, a better calculator, and my employee price would be $370." www.bizjournals.com. Wozniak had offered his Apple 1 design to Hewlett Packard five different times without success. HP made a programable electronic desktop calculator, the HP 9100A, in 1968 that could be considered an early personal computer. For marketing purposes, they called it a desktop calculator, however. Bill Hewlett said, "If we had called it a computer, it would have been rejected by our customer"s computer gurus because it didn"t look like an IBM. We, therefore, decided to call it a calculator and all such nonsense disappeared." History of the 9100A desktop calculator, 1968. The 40-pound machine was priced at $4,900, or around $37,000 in 2020 dollars! The 9100A logic circuit was built without integrated circuits. Bill Hewlett around 1970 challenged the HP 9100A developers to make a "shirt pocket" version. "I want it to be a tenth of the volume, ten times as fast and cost a tenth as much." (The HP 35, Consumer Electronics, An Origin Story, http://codex99.com/design/the-hp35.html.) The result was the HP 35 scientific calculator, followed by the HP 65 and HP 67 programable scientific calculators. The HP 9100A was the first "calculator" to use Reverse Polish Notation. https://www.calculator.org/articles/Reverse_Polish_Notation.html.

The serial number for my HP 67 starts 1703 which indicates it was manufactured in early 1977. https://www.hpmuseum.org/collect.htm#numbers. My HP 67 was made in the United States, perhaps at the HP Corvallis, Oregon facility, which is located on the Willamette River and near Oregon State University. The Corvallis Gazette-Times on August 8, 1974 indicated HP planned to build a calculator and research facility in Corvallis. Moving day was in September 1976. "Report from Corvallis: Now that the dust has settled . . .," Measure magazine (August 1978). See "How Hewlett-Packard layoffs were avoided by founders Bill and Dave," Tom"s OSU, October 15, 2016. Prior to the Corvallis facility, calculators were made at the Advanced Products Department in Cupertino. See vintagecalculators.com ("At first the HP-35 was made only in the USA (at the Advanced Products Department in Cupertino - the calculator division moved subsequently to Corvallis"). HP still markets calculators today. The manufacturing and much design are done overseas, however. For example, the HP 35s programable scientific calculator, which was introduced in 2007 to commemorate the 35th anniversary of the introduction of the HP 35, was designed in Taiwan and made in China. https://www.embedded.com/tear-down-scientific-calculator-boils-design-down-to-two-ics/.

HP 12c, financial calculator using Reverse Polish Notation (RPN). First introduced in 1981, the HP 12c is still sold today! According to ajc.com/business (Atlantic Journal-Constitution), HP claims it is the oldest consumer electronic device still made. The new on-line price at hp.com is $69.99. With RPN, you add 2 + 3 with the following keystrokes: 2 Enter 3 + . This takes getting use to. hp.com has considerable information availble including features and specifications, and the 211 pagemanual. See also Museum of HP Calculators. Purchased at a garage sale 9-10-05 for $.25. Good cosmetic and excellent working condition. No case or manual. USA stamped on the back with serial number 2902A32194. The 12c has been made in other countries but apparently the USA ones are the most valued. (See Museum of HP Calculators). If anyone knows the approximate date of manufacture of my calculator, please e-mail me.

Hewlett Packard 15C (1982-1989) (Large Image) Advanced programmable scientific calculator using Reverse Polish Notation. It shares a similar design with the HP 12C financial calculator above. Both are part of the HP 10C series which included the HP 10C basic scientific calculator, HP 11C mid-range scientific calculator, HP 12C financial calculator, HP 15C advanced scientific calculator and the HP 16C computer programmer calculator. (HP 10C Series - Wikipedia.) The HP 15C was made from 1982 to 1989. It originally cost $135. That"s about $315 in 2011 dollars - the price of a discount laptop computer. (For example, on the day I bought my HP 15C my local Radio Shack had a laptop computer on sale for $300.) While the HP 15C hasn"t been made for over 20 years, it still has a following. Bring Back the HP 15C seeks to have HP resume production. 14,847 people in 175 countries have signed a petition stating they would buy 83,363 HP 15c calculators. (Curiously, that"s an average of 5.6 calculators per person.) That site states the HP 15C is the best scientific calculator ever made by anyone for everyday use. Reasons: It uses Reverse Polish Notation (RPN) which is more efficient and natural, it was the smallest RPN calculator made by HP, the keyboard feel is very close to perfect, the landscape keyboard layout where you press keys with your two thumbs is better than a portrait layout where you press keys with one index finger, it has great battery life, the owner"s manual is top notch, and it is the coolest looking calculator ever made! HP 10c Series - Wikipedia states it sells used for between $200 and $400. On the day I bought mine (July 23, 2011), one sold on eBay for $419! The range on eBay for about the past 15 days was from $92 to $600 with 25 of them sold. I bought mine at a garage sale in the San Carlos area of San Diego for $1.00! It is in good working and cosmetic condition. It was pretty dusty with some yellowing of the covering over the screen. It works fine, however. It did not come with the cover or manual. There are computer simulators at Hewlett Packard 15C - A Simulator for Windows, Linux and Mac OSXand athp15c.com. As explained at hpmuseum.org the HP 15C supports a lot of advanced math including complex numbers, matrix math and many things beyond my comprehension! It uses three 1.5 volt LR44, S76 or similar button cell batteries which are readily available today. UPDATE: I was looking at amazon.com on 9-16-11 and noticed that HP now does sell a new edition of the HP 15c for $99. It"s the same as the old one but up to 100X faster. Pretty cool - an electronic product being reintroduced after 22 years! The petition referred to above apparently worked! Congratulations.

Hewlett Packard 28C (Introduced 1987) (Large Image, Closed) "The HP-28C was the first handheld calculator capable of solving equations symbolically." (HP 28C - Wikipedia.) It was also HP"s first graphing calculator. It has a clamshell design with 35 keys on the left side and 41 keys on the right side. It is powered by three 1.5 volt N cells. Many sites have detailed information on the HP 28C including hpmuseum.org and americanhistory.si.edu. The original price was $235. The basics of use are in the 262 page Getting Started Manual. I have two of these. They were a generous gift in April 2011 and a wonderful addition to the museum.

Canon Pocketronic, truly historic, the Pocketronic was the first pocket calculator. (For big pockets or hands - it"s about 8" x 4" x 2".) It is a direct product of Texas Instrument"s "Cal-Tech" project. The Cal-Tech (i.e. calculator technology) project set out in 1965 to use integrated circuits to build a calculator that could fit in one"s hand. The project was completed in 1967 with several working prototypes. Texas Instruments sought out a manufacturer and Canon, noted for its cameras, was interested to increase it business machine business. The result was the Canon Pocketronic released in Japan in April 1970. (I was in 7th grade.) It is very similar to the Texas Instruments prototypes including having a horizontal paper printout. It has no LED, LCD or other display - just the printout. It is powered by 13 rechargeable Ni-Cad batteries. It originally sold for $395, over $1,950 in today"s dollars!

The Cal-Tech program is discussed at the datamath site. On the left menu, click "History" and then "Datamath story". The datamath site also has a good article on the Canon Pocketronic which it describes as "the most important calculator in the history of Texas Instruments." On the main menu, go to "Calculators related to Texas Instruments," then to "Canon," then to the "Pocketronic." The datamath site also has several additional pictures. Vintage Calculators also has an excellent article on the Pocketronic and the Cal Tech project. See also Old Calculator Museum. Instructions.

Canon Canola L121 (circa 1971) (large image) www.datamath.org states the first desktop calculator using Large Scale Integrated (LSI) circuits. According to Wikipedia an integrated circuit is a miniaturized electronic circuit etched onto a semiconductor material such as silicon. A large scale integrated circuit has tens of thousands transistors per chip. (See also webopedia.) Describing the L121 as a breakthrough in technology, www.datamath.org has photos and descriptions of the four main integrated circuits in the L121. The L121"s display used Nixie tubes which are sort of like vacuum tubes with 10 layers inside, each representing one of the numerals 0-9. (See Wikipedia.) After this time, Nixie tubes were rapidly replaced by orange Panaplex displays by Burroughs which appear to be like flat Nixie tubes, Light Emitting Diodes (LED), Vacuum-Fluorescent-Displays (VFD), and Liquid Crystal Displays (LCD). Each used progressively less power allowing more pocket sized devices. (See Datamath"s Display Technology of TI Calculators).

The Old Calculator Web Museum has a detailed discussion of the L121 including how the calculator sparked the interest of that Web site"s author as a youngster in an eventual career in computer science. I myself acquired an L121 because it reminded me of the electronic desktop calculator that was demonstrated by a speaker in my 8th grade math class. As indicated before, I was amazed at what the machine could do. I have no recollection of what brand or model of calculator it was, but it would have been the same vintage as an L121. John Wolf"s Web Museum has an excellent display of early Canon desktop calculators including the L121. Be Calc has some excellent close-up photos the L121 components. It lists a date of 1970, a year earlier than other sites. Classroom Tech shows a somewhat similar Monroe 620 made by Canon. I purchased my L121 on eBay on 6-16-06 for $9.99 plus $16.25 shipping from Oklahoma. It is in good working and operating condition with a cover and power cord.

Canon Palmtronic LE-10 (January 1972) Canon"s first LED display pocket calculator, following the Bowmar 901B introduced September 1971 by only a few months. Datamath.org states the original price was $259 or over $1,250 in 2006 dollars! It is a very solid machine with a very clear LED screen and ten digits. It runs on either a NiCad battery pack or four AA batteries which fit into a removable holder. It has an analog battery meter. To charge the NiCad Battery pack you fit the calculator on a cradle apparently attaching it with a screw that fits in a screw mount on the calculator. The screw mount happens to be the same size as a tripod mount; hence, it"s the only calculator I know that mounts to a tripod!

I purchased this on eBay on 6-13-06 for $15.75 with $5 shipping - a great deal! It is in near new cosmetic condition and operates perfectly. It includes the original (box), manual and cover, all in excellent condition. It also comes with a battery holder for AA batteries as well as a NiCad battery pack. Both the holder and the separate NiCad pack look new with absolutely no corrosion. It did not include the cradle for charging and AC operation, however. Datamath.org has some excellent photos of the charging craddle and internal views of the calculator. While made in Japan, the calculator uses Texas Instruments chips and display modules.

According to Datamath there were actually four versions - the LD-8M 2 with a Hitachi HD36364 calculator circuit and a smaller display, the LD-8M 3 with a Texas Instruments TMS1042 calculator circuit, one with a NEC uPD946C circuit, and the LD-8M4 which again uses the Hitachi HD36264 calculator circuit. As can be seen in the Datamath photos, the circuit board configurations for the four versions are all quite different. As seen in this photo, mine is the second version, LD-8M 3, which uses the Texas Instruments calculator circuit. The case snaps together and can be opened by carefully prying the edges. The keyboard circuit board sits and top of the main circuit board. The two are joined together by twenty pins. (See photos at mycalcdb.) I separated the boards only slightly in order to be sure to not break the pins. The calculator runs on two 1.5 volt AA batteries. It also has a port at the top to connect to an AC adapter. I do not have the adapter. Canty"s Bookshop in Canberra, Australia has a wonderful ode to a Canon Palmtronic 8M that finally bit the dust.

My Canon Palmtronic LD-8M3 was a generous gift from a woman in Windsor, United Kingdom. The calculator belonged to her dad. It is in good cosmetic and operating condition. The gift also included her mother"s Philips Pocket Memo 390 mini-cassette recorder with 16 mini-cassettes. The package was wrapped in a lovely black ribbon with an old military brass button that found in soil near Windsor Castle!

Commodore, a U.S. company, sold adding machines in the late 1960s and sold the Commodore C110, a rebranded Bowmar, by late 1971 or 1972. They then starting making their own calculators in the US, UK, Japan and Hong Kong. In 1976 they bought chip manufacturer MOS Technologies Inc., whose chips were used in Apple II, Attari 800 and Commodore PET and 64 computers. By the late 1970s Commodore got out of the unprofitable calculator market to concentrate on computers, a market which itself became unprofitable for Commodore and others. As indicated previously, my first scientific calculator was a Commodore, I believe Model No. SR4148R discussed at Vintage Technology.

Commodore 207 adding machine, made in Japan. Commodore originally sold typewriters then adding machines. They began importing their adding machines from Japan by 1965. By the early 1970s they concentrated on electronic calculators instead. This machine therefore dates from about 1965 to 1970. Compared to a pocket calculator it is huge - about 5.5" x 7.5" x 11" and weighing over ten pounds. It really only adds and subtracts, although it has a X key for repeat addition. Purchased at a yard sale in the Clairemont area of San Diego on 4-29-06 for $.50. It appears to be in good working condition although I have not tried it out with a tape and new ribbon. The cover comes off by moving two tabs at the bottom. See Internal View. It is a mechanical calculator utilizing the same basic technology as the Dalton adding machine below from the 1920s or before. The mechanics are powered by electricity.

Commodore Minuteman 1 (Large Image) Also known as Model MM-1, the Minuteman 1 was introduced in January 1972. This was among the earliest pocket calculators with the Canon Pocketronic being introduced in Japan in April 1970 and the Bomar 901B and similar Commodore C110 being introduced in September 1971. History of Calculators - Timeline. See also Timeline, datamath.org, and Commodore Calculators. Relatively large at roughly 6 x 3.5 x 1.5 inches. Klixon keyboard. The calculator pulls apart - one half is the battery back, the other half is the calculator. Two pins in the "Power Pak" section fit into two holes in the metal plate of the calculator section. The electrical connection is made at the top with two pins in the calculator section fitting into two holes in the "Power Pak" section. (Half Sections) Red 8 digit LED display.

There are no tops on the number 6, but unlike the Commodore Minuteman 2 below, it does have full height zeros. Made in USA by Commodore, Santa Clara, California. Serial No. 19197. Four basic functions only with += and -= keys. Mine was generously donated to me in March 2009 from a man in Ontario, New York. The six NiCad batteries do not appear to have leaked, but I assume they no longer hold a charge after nearly 40 years. It is in excellent cosmetic condition. It works with the included AC adapter. The only problem is one of the seven segments in the far right LED is not working. You can decipher what the number is for most numbers, although an 8 will look the same as a 9. Basic instructions are on the back of the calculator. (Back View) According to datamath.org, it cost $118 in 1972, which equals about $600 today, the price of a decent full size laptop computer or two budget "netbook" computers.

Commodore Minuteman 2 Introduced June 1972 according to History of Calculators - Timeline. See also Timeline. Appears to be the third Commodore pocket calculator made after the C110 which is based on the Bowmar 901B (1971) regarded as the first true pocket sized LED calculator and the similar Minuteman 1 (see datamath.org) made earlier in 1972. See Commodore Calculators. (Also at Vintage Calculators.) Relatively large at 6 x 3.5 x 1.5 inches. Klixon keyboard. There appears to be multiple keyboard designs for the Minuteman 2. Mine has all black keys except for the red C (Cancel) key and the on-off switch is on the bottom. The "Power Pak" with 6 rechargeable AA batteries comprises the entire bottom half of the calculator. (Internal View.) Also runs with AC adapter.

Sanyo Mini Electronic Calculator ICC-0081. Introduced January 1971 according to datamath.org, making it one of the earliest portable, battery operated, electronic calculators succeeded by only a few other such as the similar Sanyo ICC-82D, Canon Pocketronic, and the Sharp EL-8. It cost $425 in 1971 which has the same buying power as $2,360.47 in 2011 dollars. For the equivalent price you can buy several iPhones or several laptop computers today. The ICC-0081 only does the four basic operations. It has an eight digit Nixie tube display. You could enter, and the calculator would display, up to 16 digits, however. That"s pretty impressive since a lot of simple calculators today handle only 8 digits. As I write this, the Windows 7 calculator on my computer does at least 32 places. Incidentally, the computer and monitor I"m using cost only $300 in 2011. While portable, this calculator was not yet a pocket calculator. According to the specification in the ma