graphic lcd display programming free sample

In this project, I will show you how to interface a 128X64 Graphical LCD with Arduino UNO. This particular LCD Module is based ST7920 LCD Controller. So, we will first see a little bit about the Graphical LCD Module and its LCD Controller ST7920.

In the previous Arduino project, I have interfaced a Nokia 5110 LCD Module with Arduino. It is also a graphical LCD which can display some basic bitmap images and graphics. But the issue with Nokia 5110 LCD Module is its resolution.

At 84 x 48 pixels, the Nokia 5110 LCD can be used for implementing a menu-based user interface. Due to its small size, the resulting menu will be limited to 3 or 4 items per page.

If we want a bigger display with more real estate to work with, then the obvious choice is to go for the bigger and better 128×64 Graphical LCD Module.

As a demonstration, after making all the hardware connections, I will display a bitmap image on the Graphical LCD Module. If you are interested in implementing a simple 16×2 Alpha-Numeric LCD with Arduino, then check out this tutorial.

At first glance, the 128×64 Graphical LCD Module seems like a bigger brother to the famous 16×2 LCD or 20×4 LCD Modules, with their similar construction and almost similar pin layout.

But there is a significant difference between those two. 16×2 or 20×4 LCDs are essentially character displays. They can only display alpha-numeric characters and some simple custom characters that are confined to a 5×8 matrix.

By using different combinations of pixels, we can basically display characters of various sizes. But the magic doesn’t end there. You can display images and graphics (small animations) as well. In a 128×64 LCD Module, there are 64 rows and 128 columns.

There are several versions of the Graphical LCD in the market. Even though the usage, application and implementations are almost identical, the main difference lies in the internal LCD Controller used to drive the dot matrix display.

Some of the commonly used LCD Controllers are KS0108, SSD1306, ST7920, SH1106, SSD1322, etc. The pin out of the final LCD Module might vary depending on the LCD Controller used. So, please verify the LCD Controller as well as the pin out before making a purchase.

The Graphical LCD Module I purchased consists of ST7920 Controller. It is manufactured by Sitronix and supports three types of bus interfaces i.e., 8-bit mode, 4-bit mode and Serial interface.

If you have used 16×2 LCD Display earlier, then you might be familiar with both 4-bit as well as 8-bit parallel interfaces. The serial interface is something new and we will explore this option in this project.

As I already mentioned, double-check with the manufacturer about the pinout of the Graphical LCD Module. The following table describes the pinout of the 128×64 LCD Module that I have.

Now that we have seen a little bit about the Graphical LCD and its controller ST7920, let us now proceed with interfacing the 128×64 Graphical LCD with Arduino. I will implement a simple circuit to demonstrate how easy it is to interface the LCD and Arduino using very few external components.

So, connect the RS, RW and E of the LCD to Digital IO pins 10, 11 and 13 of Arduino UNO. Also, in order to select the Serial Interface Mode, the PCB pin must be connected to GND.

The remaining connections are similar to a traditional 16×2 LCD. VCC and GND are connected to 5V and ground of the power supply. VO is connected to the wiper of a 10KΩ POT while the other two terminals of the POT are connected to 5V and GND respectively.

Instead of displaying characters of different fonts (yes, there are libraries using which you can implement various fonts), I will straight away display an image in the form of bitmap. Before writing the code, you need to convert the bitmap image into byte arrays.

I have used the above “The Office” logo. Remember that the resolution of the 128×64 LCD is, well 128×64 pixels. So, the maximum image size should be 128×64. So, using Microsoft Paint, I have brought down the resolution of the above image to 128×64 pixels and also saved it as Monochrome Bitmap Image.

A simple project for interfacing the 128×64 Graphical LCD with Arduino is implemented here. Instead of displaying plain characters, I have displayed a bitmap image on the LCD to show its capability.

In this tutorial we will see how to interface and graphical LCD(GLCD) with PIC16F877A. In this tutorial we will look at interfacing KS0108 controller based JHD12864E display. There are many displays out there based on KS0108 or compatible display controller. They all work the same way, but make sure to check the datasheet for the pin diagram before doing the connection.

We will look at the working of the display, the hardware setup and programming with PIC16F877A. You may use any other AVR,8051,PIC,ARM controller as well. We have it tested and working on 8051, AVR, PIC and ARM. We have similar tutorials on these MCUs as well.

Unlike a 16 x 2 display, this does not have a character map for ascii values stored on its ROM. However it allows us the flexibility of creating fonts like Arial, times new roman etc. We could also display bit-map images on it and stretching it little further we can make GUI"s and little animation, but that"s for another day. So lets get started.

Below is a snippet of the example LCD control code. This small novella of a sketch shows off an array of graphics driver functions, character drawing tools, and other useful functions to help you get started using the LCD. You will need to include the LCD_Functions.h header in the same directory as the sketch folder from the download. Otherwise, your code will not compile when uploading to Arduino.

Heads up! If the display is not showing pixels even with the correct logic levels and example code, it may just have slight variances in the way that they were manufactured. You can see the pixels faintly on the screen at an angle or pushing down on the LCD. You will need to try and set the contrast where it says setContrast(40) on line 87 to a value of 60. There is probably some variances in the LCD’s contrast which might explain why certain LCDs have issues displaying defined pixels on the screen.

Once uploaded to your Arduino, the sketch will begin by running the demo -- a set of basic animations and graphics functions. To begin, we"ll draw some random pixels on the screen ("It"s full of stars..."). Then we"ll move on to examples of drawing lines, rectangles, and circles. Throughout there are examples of drawing characters and strings. Finally the demo closes out with an homage to a monochrome comic which seems a perfect fit for this little monochrome LCD.

After the demo runs its course, the sketch will enter into a serial echo mode. Open the serial monitor (set the baud rate to 9600 bps), and type stuff over to the Arduino. It should start printing everything you send it onto the LCD.

The Graphic Serial LCD Backpack is designed to be controlled by a variety of means. One of which is through a serial terminal. This can be useful if you want to use a personal computer as your control device. You can also send commands to the backpack in real time using the ASCII commands. This is useful for testing the LCD before embedding it into a project. Here is a full list of the ASCII commands.

I have another tutorial if you are interested in 16×2 LCD Displays with the Pi.  Unlike the 16×2 which is primarily simple text, the graphics LCD makes it easy to draw graphics, different size text in any font and even play games or show animations.  This is the Adafruit ST7565 graphics negative LCD display:

It can be powered directly from the Pi’s 3.3 V rail.  It requires 5 GPIO pins for data.  The display has a negative RGB back light which allows you change the foreground color.  An additional 3 GPIO pins are required if you want to control the color from the Pi.

Here is a simplified wiring schematic.  CS (Chip Select), RST (Reset) and A0 (Register Select) can be connected to any 3 GPIO pins. I’m using 8, 25 and 24 respectively which are the default values.  Different values can be specified as parameters when you instantiate the ST7565 Python class.  SCLK (Serial Clock) on the GLCD goes to GPIO 11 which is the Pi’s serial clock.  SID (Serial Input Data) on the GLCD goes to GPIO 10 on the Pi which is MOSI.  You must use GPIO 10 and 11 for SID and SCLK.  Vdd is connected to a 3.3 V pin on the Pi and the grounds are also connected.

The RGB back light LED pins can go to GPIO’s 16, 20 and 21. You can use any GPIO pins for these (in the video I used 8, 10 & 11).  There are no default values.  To control the color from the Pi you must specify the RGB pins when you instantiate the ST7565 class.  Resistors are placed in series to limit the current. I’m using 51 Ω which provides ample brightness. Since the back light is common anode, the back light anode a+ pin is connected to the Pi’s 3.3 V power. The back light LED’s are turned on by grounding the cathode pins.  You could go brighter with lower ohm resistors but you would need to use transistors because you do not want to exceed the maximum GPIO current which I believe is 16 mA per pin with a combined total not to exceed 50 mA.  Please note that the display has a 100 Ω resistor built-in on the red channel.   The resistor is visible on the back of the display and is not mentioned in the datasheet.

The display is 128 pixels wide by 64 pixels high.  The display is broken into 8 horizontal pages.  The pages are confusingly numbered from the center 0 to 3 and 7 to 4.  Each page is comprised of 128 columns of 8 vertical pixels.  To address the pixels you specify the page and the column number and then send a byte to fill 8 vertical pixels at once.

Don’t worry if this seems confusing because I went ahead and wrote a Python library to handle all the drawing for you.  It uses a back buffer that can be addressed with simple X, Y coordinates.  And just for the record, this display has a 9th page on the bottom but it only has 1 row of pixels so I omitted it to make the programming easier.

The display is connected to the Pi using SPI which stands for Serial Peripheral Interface.  My previous tutorial on AVR programming with the Pi details SPI which usually requires 3 lines MOSI, MISO and Clock.  The Pi is the master and the GLCD is the slave.  Since we are only writing to the GLCD and not reading, we only need to connect the MOSI and Clock lines.  MOSI is the output from the pi to the GLCD and the clock synchronizes the timing.

I didn’t write an install because it’s only 2 files.  You can place them in the same folder as your program or append the system path with their location.  The main ST7565 library (st7565.py) which handles drawing, text & bitmaps, and a font module (xglcd_font.py) to load X-GLCD fonts.

I commented the methods pretty well and I added docstrings detailing all the parameters and usage if you need more help.  Here are some basic LCD commands:

Clear_display clears the GLCD.  Clear back buffer clears the back buffer.  You would issue both clear commands to start with a clean slate.  Flip sends the back buffer to the display.  I probably should have named the flip method present because the buffer is copied to the display and not swapped.

Set_backlight_color allows you to change the LED back light color.  The RGB values are specified in percentage points 0 to 100.  The software uses pulse width modulation to control the LED’s for greater color range.  It also enables you to change the brightness of the display.  You must specify the RGB pins when you instantiate the class to enable color control from software.   Set contrast changes the display contrast.  A great feature of this display is the ability to control brightness and contrast in software.  Sleep and wake take the display in and out of power saving mode which uses less power than the standby mode.

Here is an example that draws rectangular border around the display.  Don’t forget to initialize the display after importing and instantiating it.  Also please note that all drawing commands operate on the back buffer.  Nothing will appear on the display until you fire the flip command.

Draw letter draws a single letter.  You can specify an X-GLCD font.  X, Y are the top left coordinates of the letter.  Invert acts a little different from the drawing commands.  It just inverts the letter (dark text on an illuminated background.)  Landscape draws text along the long axis of the display.  If set to false the text is rotated and drawn along the short axis.  Draw string, draws a string of characters.  You can specify pixel spacing between letters.

Several fonts are included with my library.  Plus, you can convert most TrueType fonts to X-GLCD format using the free edition of MikroElektronika GLCD Font Creator.  Click Import an Existing System Font to load any TrueType font on your system.

The default options should be OK.  You might want to change the font size.  Once loaded there is a rich set of features to edit the font characters.  Click Export to GLCD to start the conversion.  Make sure you select the mikroC tab and X-GLCD lib format.  Then click save.  I like to include the font pixel width and height in the name because you’ll need it later to load the font.

Unfortunately, this program is Windows only.  Also if you are using a version higher than XP, you’ll need to run GLCD Font Creator in XP compatibility mode or else the save button will not work.  Right click on the program shortcut and click properties.  Select the compatibility tab and choose Run this program in compatibility mode for: Windows XP (Service Pack 3):

Draw_bitmap draws a 2d array of pixels where X, Y are the top left corner of the image.  Load_bitmap is used to load a bitmap file into a 2d NumPy pixel array.  Path is the location of the bitmap file.  You have to specify the actual pixel width and height of the bitmap if the dimensions do not equal the size of the display.  Save_bitmap saves the screen to a raw bitmap file.

Only raw 8-bit monochrome bitmaps are supported, but you can convert graphics files such as JPEG to raw format using IRFanView for Windows or with GIMP which works on MAC and Linux too.  Both programs are free.

The image pixel size cannot be larger than the GLCD screen size.  The file size of the raw bitmaps should equal the pixel width times the pixel height.  For example, if you convert a 32×32 JPEG, the new raw bitmap file should be 1,024 bytes (32 X 32 = 1,024).  If it doesn’t then something went wrong during the conversion.

The program demonstrates rotating different size regular polygons.  It also uses text to display the angle and draws a small space ship in the corner.  Each loop draw the polygons twice at the current and previous position.  This makes for a more fluid animation.

The main loop draws the clock face and the date display.  Then the draw_line method is used for the minute and hour hands.  It repeats when the minute changes.

If we use 14 pins for GLCD, pins left for other tasks = (17-14) = 3. That is impractical for any application. So effectively, we could as well decide not to use 28-pin device for GLCD.

Another issue is that, if your controller is 3.33V, you will have to read the LCD data sheet and make sure that the VIH and VIL are OK for 3.33V inputs.

I was inspired with the 2 wire -- clock and data scheme using 74HC595 very famous to drive character LCD. Please refer to this link (Bill"s version): -

1. Only 2 wires required ( additional 2 wires for 5V and GND). There are 1 wire version as well for LCD interface, but that is more complex. If we extrapolate the trend, we could also achieve 0-wire scheme (say by using bluetooth), but that is even more complex.

Click on the image to see a zoomed version. The 20-pin header is the one that will fit with connector on LCD module. Pleas refer to the LCD module data sheet (bottom of web page) to know the pin description of LCD module.

In this tutorial i am going to teach you how to interface graphical lcd 128×64 with 8051(89c51,89c52)microcontroller. 128×64 means that lcd has 128 coulombs and 64 rows. Which means you can make your desired image or text in 128×64 matrix square. Graphical lcds comes in many sizes, they also differ in characteristics. Some can be directly connected to your PC and you just need to learn simple commands to send pictures and text to lcd, these graphical lcds comes with free software with them. Some are just simple lcds and you need to control them with some intelligent unit like microcontroller etc. In this tutorial we are going to control the same simple graphical lcd using 89c51 microcontroller. We will display text on graphical lcd using 8051 microcontroller.

I am going to interface jhd12864e graphical lcd with 8051 microcontroller.To learn about full pin description and internal organization of pixels of jhd12864e graphical lcd please go through the simple tutorial. This will lead you to easily understand the code written below.

The above tutorial is very important to understand the GLCD code below. If yon don’t know about the GLCD working then you can not understand the 8051 microcontroller with GLCD code below. Pin out of GLCD jhd12864e is given below.

I am going to print my website name “microcontroller-project.com” on glcd. First i decided text font to display on GLCD. II finalized the character height to 8 rows and 5 to 6 coulombs in width. You can display text according to your desire. Since you have lot of available space from 128 coulombs to 64 rows. Combine pages to make font greater and greater(If you don’t know what is page in graphical lcd please go through the upper tutorial).

Now when you are done with initializing glcd and selected glcd half and page. Its time to make/display text or image on glcd. Each page of GLCD is organized in rows and coulombs (8×64 in dimension) 8 rows and 64 coulombs. Each coulomb in a page has 8 dots aligned vertically. We send an eight bit data to make these dots ON or OFF. 0 is OFF and 1 is ON. A simple command like FF=11111111 makes all dots of coulomb ON & F0=11110000 makes first four dots OFF and last four ON. You make your desired text or image by making these pixels ON or OFF. The combination of all coulombs makes a picture.

For example to display the ‘M‘ character on Glcd the data send to GLCD is below. Data is send to glcd 8-bit at a time. 8-bit data is in hexadecimal format. If we translate hexadecimal to binary it will represent the below character. Last command is not displaying any thing. Its actually the gap for another character to appear a head of ‘M‘.

Circuit diagram of the project is simple. Connect Port-1 of 8051(89c51,89c52) microcontroller with data pins of graphical lcd. Port-3 pin 0 is connected to rs(register select) pin of graphical lcd. Port-3 pin 1 is connected to rw(read-write pin of graphical lcd). Port-3 pin 2 is connected to en(enable) pin of lcd. Port-3 pin 3 and 4 are connected to cs1(chip select 1) and cs2(chip select 2) to 128×64 graphical lcd. Port-3 pin 5 is connected to reset pin of 128×64 graphical lcd. Rest of the connections are for 8051 microcontroller initialization. Circuit diagram of the project is below.

Coming to code of GLCD project. it is written in c language using keil uvision 3 software to compile and create hex code. First the header file reg51.his included(it is to be included in every project made in keil for 8051 microcontroller). Then single bits of Port-3 are defined. These pins are used to control jhd12864e graphical lcd. delay() function is generating some delay for us to be used where necessary. lcdcmd() function is sending commands to glcd. lcddata() function is sending data to glcd. The main function is controlling all the displaying and control functions. Each command is commended with its function.

Note: Some graphical lcds select cs1, cs2(chip select) on 1 and some with 0. If you are using this code be sure that 0 selects your cs1 & cs2. If not 0 then switch cs1 & cs2 in the code just make cs1=1 where it is 0 and cs2=0 where it is 1.

It is suitable for monochrome (black and white) LCDs with page by page data and command write style data transfer protocol. It is not compatible with color graphic LCDs.

Not all combinations of microcontroller platform and LCD controllers are supported out of the box. However you can edit the files devices/ and controllers/ and add your desired combination. More information on how to do this can be read in the doxygen documentation.

For the Newhaven displays using ST7565 based controllers listed above which have been tested as working, there are certain initialisation sequences which should be followed, and this may vary from display to display. To force a certain (and tested) initialisation sequence, define one of the following:

If you don"t specify a NHD model, ST7565 controller selection will default to GLCD_INIT_NHD_C12864WC_FSW_FBW_3V3_M sequence. This however may change in the future.

Set GLCD_LCD_WIDTH and GLCD_LCD_HEIGHT to define custom LCD dimensions. If these are not user defined, then a default width and height is used. The default dimensions are 128x64 except for PCD8544 controllers which is 84x48.

The code samples above will have the glcd library code already inside it, however I haven’t made any attempt to keep the glcd library updated in the examples so I advise that if you are using the example code, to replace the glcd directory (usually in library/glcd or lib/glcd) with the latest updated code.

Download our Crystalfontz LCD Software. We provide software for you to test many types of LCDs including character displays and graphic displays. Our character and graphic USB display modules can use CrystalControl2 to quickly set up the display. Bitmap to ePaper and Image2Code provide a simple interface to add an image to your display. We also USB LCD drivers and demonstration code for Linux.

We come across Liquid Crystal Display (LCD) displays everywhere around us. Computers, calculators, television sets, mobile phones, and digital watches use some kind of display to display the time.

An LCD screen is an electronic display module that uses liquid crystal to produce a visible image. The 16×2 LCD display is a very basic module commonly used in DIYs and circuits. The 16×2 translates a display of 16 characters per line in 2 such lines. In this LCD, each character is displayed in a 5×7 pixel matrix.

Contrast adjustment; the best way is to use a variable resistor such as a potentiometer. The output of the potentiometer is connected to this pin. Rotate the potentiometer knob forward and backward to adjust the LCD contrast.

A 16X2 LCD has two registers, namely, command and data. The register select is used to switch from one register to other. RS=0 for the command register, whereas RS=1 for the data register.

Command Register: The command register stores the command instructions given to the LCD. A command is an instruction given to an LCD to do a predefined task. Examples like:

Data Register: The data register stores the data to be displayed on the LCD. The data is the ASCII value of the character to be displayed on the LCD. When we send data to LCD, it goes to the data register and is processed there. When RS=1, the data register is selected.

Generating custom characters on LCD is not very hard. It requires knowledge about the custom-generated random access memory (CG-RAM) of the LCD and the LCD chip controller. Most LCDs contain a Hitachi HD4478 controller.

CG-RAM address starts from 0x40 (Hexadecimal) or 64 in decimal. We can generate custom characters at these addresses. Once we generate our characters at these addresses, we can print them by just sending commands to the LCD. Character addresses and printing commands are below.

LCD modules are very important in many Arduino-based embedded system designs to improve the user interface of the system. Interfacing with Arduino gives the programmer more freedom to customize the code easily. Any cost-effective Arduino board, a 16X2 character LCD display, jumper wires, and a breadboard are sufficient enough to build the circuit. The interfacing of Arduino to LCD display is below.

The combination of an LCD and Arduino yields several projects, the most simple one being LCD to display the LED brightness. All we need for this circuit is an LCD, Arduino, breadboard, a resistor, potentiometer, LED, and some jumper cables. The circuit connections are below.

With the integration of Bridgetek’s next generation EVE3 BT815/BT816 Embedded Video Engine IC, Matrix Orbital EVE3 SPI TFT"s deliver clean, crisp, full color TFT screens for interactive menus, graphing, graphics and even video..

CategorySub CategoryFile NameRevisionSizeDescriptionNotesFeaturesChange LogCategorySub CategoryFile NameRevisionSizeDescriptionNotesFeaturesChange LogEVE3 DisplayEVE3x-391.11.73MiBEVE3x-39A/G Manual

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.

The origins and the complex history of liquid-crystal displays from the perspective of an insider during the early days were described by Joseph A. Castellano in Liquid Gold: The Story of Liquid Crystal Displays and the Creation of an Industry.IEEE History Center.Peter J. Wild, can be found at the Engineering and Technology History Wiki.

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 1964, George H. Heilmeier, then working at the RCA laboratories on the effect discovered by Williams achieved the switching of colors by field-induced realignment of dichroic dyes in a homeotropically oriented liquid crystal. Practical problems with this new electro-optical effect made Heilmeier continue to work on scattering effects in liquid crystals and finally the achievement of the first operational liquid-crystal display based on what he called the George H. Heilmeier was inducted in the National Inventors Hall of FameIEEE Milestone.

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.

A comparison between a blank passive-matrix display (top) and a blank active-matrix display (bottom). A passive-matrix display can be identified when the blank background is more grey in appearance than the crisper active-matrix display, fog appears on all edges of the screen, and while pictures appear to be fading on the screen.

Displays having a passive-matrix structure are employing Crosstalk between activated and non-activated pixels has to be handled properly by keeping the RMS voltage of non-activated pixels below the threshold voltage as discovered by Peter J. Wild in 1972,

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.

Twisted nematic displays contain liquid crystals that twist and untwist at varying degrees to allow light to pass through. When no voltage is applied to a TN liquid crystal cell, polarized light passes through the 90-degrees twisted LC layer. In proportion to the voltage applied, the liquid crystals untwist changing the polarization and blocking the light"s path. By properly adjusting the level of the voltage almost any gray level or transmission can be achieved.

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.

Most of the new M+ technology was employed on 4K TV sets which led to a controversy after tests showed that the addition of a white sub pixel replacing the traditional RGB structure would reduce the resolution by around 25%. This means that a 4K TV cannot display the full UHD TV standard. The media and internet users later called this "RGBW" TVs because of the white sub pixel. Although LG Display has developed this technology for use in notebook display, outdoor and smartphones, it became more popular in the TV market because the announced 4K UHD resolution but still being incapable of achieving true UHD resolution defined by the CTA as 3840x2160 active pixels with 8-bit color. This negatively impacts the rendering of text, making it a bit fuzzier, which is especially noticeable when a TV is used as a PC monitor.

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.

Color performance: There are multiple terms to describe different aspects of color performance of a display. Color gamut is the range of colors that can be displayed, and color depth, which is the fineness with which the color range is divided. Color gamut is a relatively straight forward feature, but it is rarely discussed in marketing materials except at the professional level. Having a color range that exceeds the content being shown on the screen has no benefits, so displays are only made to perform within or below the range of a certain specification.white point and gamma correction, which describe what color white is and how the other colors are displayed relative to white.

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 backli