negative lcd panel quotation

LCD (Liquid Crystal Displays) have two options or display modes.Positive mode (dark characters on a light colored background) and negative mode (lighter colored characters on a darker background).

Please see Fig.1: Yellow green STN (Super Twisted Nematic) display, the background of yellow green is lighter than dark blue characters. It is a positive mode. Fig. 2 is a blue STN display, its background of blue is darker than the white characters.It is negative mode.

Negative mode displays need backlit in order to be seen. They normally use transmissive polarizers. They have better contrast and wider viewing angles in the indoor dim environment. The readability is much better than positive displays.

Of course, we can always use LED backlight in the LCD module with fewer LED chips and turn off LED backlight when not use to save power. When can also add transflective polarizer to some negative LCDs to make it sunlight readable, but the contrast will be compromised.

Positive and negative mode concept is not only limited to monochrome LCD displays (LCD panels, character LCDs, graphic LCDs etc.), it also uses for color displays, or even other display technologies.  We will categorize the displays as below,

Character LCD modules (Alphanumeric LCD display modules) with character sets: 8×1 LCD display, 8×2 LCD display, 16×1 LCD display, 16×2 LCD display, 16×4 LCD display, 20×2 LCD display, 20×4 LCD display, 24×2 LCD display, 40×2 LCD display, 40×4 LCD display. COB (Chip on Board) bonded, 4 or 8 bits parallel, SPI, I2C interface

Graphic LCD modules with dot matrix sets 122×32, graphic LCD display, 128×64 graphic LCD display, 192×48 graphic LCD display,192×64 graphic LCD display,240×64 graphic LCD display,240×128 graphic LCD display,240×160 graphic LCD display with different color LED backlights, with COB and COG (Chip on Glass) assembling technologies

Full Color TN and IPS displays with panel sizes: 1.3”IPS display, 1.44” TN display, 1.5” IPS display, 1.77”TN and IPS displays, 2.0” TN and IPS displays, 2.2” IPS display, 2.35” IPS display, 2.4” TN and IPS displays, 2.8” TN and IPS displays, 3.5” TN and IPS displays, 4.3” TN display, 5.0” TN and IPS display, 7.0” TN and IPS display, 10.1” IPS display with medium and high brightness (sunlight readable), with parallel, SPI, RGB, LVDS, MIPI interfaces.

A wide variety of negative lcd panel options are available to you, You can also choose from original manufacturer, odm negative lcd panel,As well as from tft, standard, and tn.

As we know, LCD screen is a negative display which can’t emit light on its own. It either relies on ambient light or uses LED backlight in the back as a light source. We divide LCD screen intotransmissive LCD, reflective LCD, and transflective LCDaccording to the employing mode of light. Also, we divide LCD screen into the positive display and negative display according to the light of the background part.

It is very simple, but most people can’t fully understand the meaning. We already introduced the difference between TN, HTN, STN and FSTN LCD in my previous post. The offset angle of liquid crystal in TN LCD is 90 degrees. What is that? If we see TN, HTN, STN and FSTN LCD in the perspective of view angle, it is much easier for us to understand.

For example: if the view direction of TN LCD is 6:00 o’clock direction, you will see the graphic very blurred at any angle of 3:00 o’clock or 9:00 o’clock direction. We can still see it clearly within 20 degrees of 3:00 o’clock or 9:00 o’clock direction if it is 6:00 o’clock direction HTN LCD.

NHD-C12864WO-B1TTI#-M | Monochrome Graphic COG | 128x64 Pixels | White Pixels on Black Background | White Backlight | FSTN (-) Negative Display | Mounting Holes | Non-Stocked

Newhaven 128x64 graphic Chip-On-Glass (COG) Liquid Crystal Display shows white pixels on black background. This transmissive LCD Display requires a backlight for visibility and offers a wide operating temperature range from -20 to 70 degrees Celsius. This NHD-C12864WO-B1TTI#-M display includes mounting holes. It has an optimal view of 6:00, operates at 3.3V supply voltage and is RoHS compliant.

The LMR5419 is the next entry in our series of high density 10 micron dot-gap LCD displays, to compliment our best selling negative mode graphic LCD line. Available in 8 breathtaking colors: Jade Green, Arctic White, Warm Amber, Midnight Blue, Tangerine Orange, Sunburst Yellow, Ocean Blue and Fireburst Red!

The LMR5419 is the next entry in our series of high density 10 micron dot-gap LCD displays, to compliment our best selling negative mode graphic LCD line. Available in 8 breathtaking colors: Jade Green, Arctic White, Warm Amber, Midnight Blue, Tangerine Orange, Sunburst Yellow (not shown), Ocean Blue, Fireburst Red!

Our Ultra bright Negative Mode Displays are perfect for: Audio, Instrumentation, Medical Equipment, Industrial Indoor Meters, White Goods or Handheld Applications. These LCDs utilize premium materials which offer stunning OLED appearance due to their combination of dark black (or dark blue) background and ultra bright LEDs.

Digital panel meters (or DPM) typically uses either an LCD (Liquid Crystal Display) or LED (Light-Emitting Diodes) to display information in an alphanumerical format. What are the differences between LCD’s and LED’s and how do you know which one to pick for your application? Read on to find out!

The Liquid Crystal Display (or LCD) is a form of visual display used in electronic devices in which a layer of a liquid crystal is sandwiched between two transparent electrodes. The application of an electric current to a small area of the layer alters the alignment of its molecules, which affects its reflectivity or its transmission of polarized light. Liquid crystals do not emit light directly. Instead, they use a backlight or reflector to produce images in color or monochrome.

To take it a step further, LCD displays also come in two different variations: Positive LCD and Negative LCD. Essentially, a positive LCD display features dark-colored or black numbers/letters on a light-colored background while a negative LCD display features light-colored numbers/letters on a dark background.

While the underlying technology is the main difference between LCD’s and LED’s, there are other features that set these 2 apart from each other and could help to determine which one is right for your application.

Color: DPMs traditionally have a red, green or amber/yellow display. LEDs are also available in blue or white. Tri-color (RGB) LEDs can be used to create any color. The color of a transmissive LCD is determined by the backlight LED. Therefore, color-changing digital displays are more easily implemented with LCD technology. Some high-end DPMs provide a full-color graphic display. These use LCD technology similar to what is used in a color TV.

Brightness: The typical LED display is significantly brighter than an LCD. So viewing in a bright room or in a crowded instrument cluster favors LED. The LED’s higher brightness coupled with higher contrast gives enhance readability over LCDs. However, in direct sunlight, a reflective LCD is more visible.

Viewing Angle: LED displays to have a much wider viewing angle than LCDs. When viewing an LCD display, the image clarity will become diminished when viewing the display off to the side from the center point in either direction.

Temperature: LEDs are semiconductors, so they have a wide temperature range. Other components in the meter will determine its operating temperature limits. The chemical action in the LCD slows down at low temperatures (typically <0°C), so it may require a heater for these situations. Depending on the type of LCD, the maximum temperature of an LCD meter may also be more restricted than an LED meter.

Burn-In Issues: Neither LCD nor LED displays to have burn-in issues. That is, an image is “burned in” to the display if left unchanged for an extended time. Because of this, both types of displays are considered suitable for static images, which are typical with digital panel meters.

Life: Either display type will provide years of continuous operation. However, LCDs can degrade in high humidity due to an imperfect seal between the glass plates.

Both LCD and LED technologies have their own set of advantages and disadvantages. Be sure to consider all of these factors when deciding on the right type of display for your DPM application.

At Weschler Instruments, we carry a wide selection of digital panel meters from an assortment of manufacturers in both LCD and LED displays. We also recognize that every application is different and can sometimes require custom input ranges/scales. Contact us today with your needs and one of our highly qualified salespeople will assist you.

Liquid Crystal Displays or more commonly known as LCDs are one of the most common electronic components which help us interact with an equipment or a device. Most personal portable equipment and even gigantic industrial equipment utilize a custom segment display to display data. For many portable consumer electronics, a segment LCD display is one of the biggest contributors to the overall cost of the device, hence designing a custom segment display can drive the cost down while also utilizing the display area in the most optimum manner. These displays have the lowest cost per piece, low power requirements, and a low tooling fee too.

At first thought, designing a custom segment LCD might look like a Herculean task, but trust me that it is easier than it seems. In this article, we have summarised and compared the display types and available technologies which are required to construct a custom segment LCD. We have also provided a flowchart that can act as a step-by-step guide while you design your own custom LCD. We have also provided the process we followed, a require gathering sheet we used for communicating our needs to the manufacturer, and a few other data and the quotation we received from the manufacturer.

LCD Bias– It denotes the number of different voltage levels used in driving the segments, static drives (explained later in this article) only have 2 voltage levels or 2 bias voltage while multiplex drives have multiple voltage levels. For example, 1/3 will have 4 bias voltages.

LCDs utilizes the light modulating properties of liquid crystals which can be observed by using polarizing filters. Polarizing filters are special materials that have their molecules aligned in the same direction. If the light waves passing through polarisers have the same orientation as the filter, then the molecules of lights are absorbed by the filter, hence reducing the intensity of light passing through it, making it visible.

A custom LCD is important for maximizing the efficiency of the display area by adding custom symbols and characters. It also helps in reducing the cost and improving energy efficiency of the product. A higher number of custom symbols and specified placement of numerical and alphanumerical characters make the display more informative and readable for the user. This makes it look better than the plain old boring displays we get in the market. Furthermore, we can specify the viewing angle, contrast, and other specifications which can increase durability or give a better value for money for our intended usage.  A typical Custom Segment display is shown below, we will also show you how to design and fabricate the same further in the article.

The LCD display doesn’t emit any light of its own, therefore it requires an external source of illumination or reflector to be readable in dark environments.

While designing a custom segment LCD display, we have the leverage of choosing a lot of parameters that affect the final product. From the color of the display to the illumination technique and color of illumination as well as the type of input pins. Some important considerations we need to take while designing a custom 7 segment display are - the type of display, i.e. positive or negative, illumination method, driving technique, polarising type, and connection method. All these design criteria are explained below:

Positive and negative displays can be easily distinguished by the colour of the background and characters. Some common differences between the positive and negative displays are:

So, which one should you choose? When the displays are to be used in areas with higher ambient light, we should select positive segment LCD display as it has better visibility than negative segment LCD displays without using a backlight.

As we know that LED displays don’t emit any light, hence to illuminate it and make it visible in a dark environment, we can use different methods of illumination. The most common LCD Illumination methods are compared below:

A polarizer film is the most important component of an LCD display, which makes it possible to display characters by controlling the light. There are 3 types of polarizers that can be used in the LCD display, the properties and difference are given below:

If your products need to be used with a switchable backlight, then trans-reflective reflectors are best to be used for front reflectors. If the device has to be used without backlight, then we can select a reflective polarizer for the back-panel as it gives the best contrast ratio.

If your displays have fewer segments, then static LCD drive is preferred as it is easier to control and cheaper to construct, and has a better contrast ratio. But let’s say that if the number of segments in the display are more than 30-40 then a multiplex LCD drive should be preferred as it has multiple common pins, hence reducing the total number of pins required to drive the display.

Choosing a connector type!!! For the prototyping phase or if you need to connect your LCD display on a Microcontroller directly, a pin type connector is the best and most economical option you have. If you need to connect your LCD display in a final product with a high volume of production which also requires to be extremely durable, but at the same time should not take up a lot of space, a Flex type LCD Connector will work best for you

LCDs have limited viewing angles and when seen from an angle they lose contrast and are difficult to be observed.  The viewing angle is defined by the angles perpendicular to the center of the display towards its right, left, up, and down which are denoted by the notations 3:00, 9:00, 12:00, and 6:00 respectively. The viewing angle of LCD can be defined as the angle w.r.t. to the bias angle at which the contrast of segments is legible.

To improve the viewing angle in an LCD, a Bias is incorporated in the design which shifts the nominal viewing angle with an offset. Another technique is to increase the Voltage, it affects the bias angle, making the display crisper when viewed from a direction.

For example, the viewing angle of a TN type TFT LCD is 45-65 degrees. Extra-wide polarising film (EWP) can increase the viewing angle by 10 degrees, using an O film polariser can make the viewing angles 75 degrees but these come at a cost of reduced contrast.

LCD Control chip or LCD driver chips can be mounted on the flex cable, display, or externally on a PCB. The placement of LCD control chip can affect the cost and size of the display. The 2 most common methods of chip placement are-Chip of Board (COB)and Chip on Glass(COG) which are described below:

We planned to design an air quality monitoring system for which we needed a custom segment LCD panel for an air quality monitoring device. Our product needs to display the following data: 2.5-micron and 10-micron particulate matter (PM) suspended in the air; the units should be in parts per million (PPM). CO2 in the air in PPM along with total volatile organic compounds present in the air in parts per billion (PPB). To make the product more usable, we included time in 24-hour format, Temperature in ºC, Battery status, loudspeaker status, Bluetooth status, and Wi-Fi status. And for some personal touch, we also added how good the air quality in the room is by using 3 different smileys.

We realized that it was impossible to provide all these data in a generic LCD available in the market, thus decided to build a custom LCD for our project.

A step-by-step flowchart is shown below to walk you through each and every step of selecting components and getting your custom segment LCD manufactured.

Usually, the displays are mounted at a height of 4.5 feet from the ground, thus the viewing direction was selected to be 12"O clock with an operating frequency of 64Hz. We selected a Transmissive polarizer for the front glass and a reflective polarizer for the rear glass so that the natural light can pass through the front panel and the display can achieve the maximum contrast without the need for backlighting and we opted for the pin type connectors as they are easy for prototyping and are suitable for harsh environment with a lot of vibrations and shocks which best suited our purpose.

We mailed our requirements to multiple LCD manufacturers, (you will find a lot of LCD manufacturers on the Internet). Most LCD manufacturers have competitive pricing, and reply within a week. A sample requirement sheet is shown above which a customer needs to fill to specify all the details to the manufacturer.

This is a sample Custom Segment LCD quotation we got from one of the manufacturers. As you can see, the cost is based on the quantity. Higher the quantity, lower the cost. Apart from the cost per quantity, there is one more component called tooling fees. Tooling fee is a one-time fee charged by the manufacturer. It is for the technical design, support, and customization of the product. Customization of PCB or tooling of LCD can drive the tooling price higher or lower.

A custom segment LCD can help you personalize your product while also saving the overall cost of your product. The whole process will take you around 2-3 months, which will include the designing phase, prototyping phase, and getting your custom segment LCDs delivered to your doorstep. Higher ordering quantity will reduce the cost per piece of each unit, thus driving down the cost of your final product.