Transmissive Film – Working

john April 26, 2011 No Comments

All the possible technologies come in the form of gadgets in automobiles like cars. These gadgets not only help in reducing accidents, but may also make the car more luxurious and comfortable. Some cars like the latest BMW X5 has almost 50 latest technologies integrated inside which no other cars can even think about. There will be different types of 3-D displays along with anti-crash sensors a the rear end of the vehicle. All these ideas were provided by the joint effort of two mastermind companies called Visteon and 3M. It was at the 2008 Consumer Electronics Show (CES) in Las Vegas, that they first introduced a new feature called the Transmissive Film. Now it is being used in most high-end LDC TV’s Mobile phones, digital watches and PC monitors.

What is Transmissive Film?

Transmissive Films are used to improve the clarity and brightness of LCD displays that is used on various devices. The basic principles of LCD screens are used for its working. The materials used for its manufacture are thin sheets of polymer with a thickness of only 62µm. When this material is placed inside or outside the LCD screen, the brightness, clarity and also direction control of the image increase improves by many times.

 

Transmissive Film
Transmissive Film

The main disadvantage of a LCD screen is that almost 90% of the original brightness is lost between the backlight and the image that appears on the screen. That is, only 10 percent of the original brightness is seen by the viewer.

The rest of the light is wasted by the passage through various polarizer’s, colour filters and also liquid crystal. With the use of transmissive film, the light can be again recycled and will have an efficiency of almost 120%.

Although there are clarity problems, LCD has the advantage of having greater angular view than that of transmissive films. But this problem can become a better use for transmissive films. You may not want others to sneak and take a look at the amount you withdraw from an ATM counter. Thus transmissive films help in blocking LCD images from people who look at the screen from a greater angle (angle defined by the company).

Basics of Liquid Crystal Display (LCD)

To know in depth about the working of LCD, click on the link given below.

TAKE A LOOK : LIQUID CRYSTAL DISPLAY (LCD) – WORKING

In order to discuss about LCD displays it is important to know the basics of an image. An image is comprised of millions of pixel cells. A pixel can be defined as the smallest visible block of an image. To show an image in an LCD display, these pixels have to be shown on the screen. If it is a color image, each pixel will again be broken down to three sub-pixels. Each sub-pixel will be assigned a color – red, blue, or green. By controlling the intensity of light that is available to each red, green and blue sub-pixel, you get the different images on the LCD screen.

The real role of liquid crystals has not yet been defined. The intensity of light which hits the sub-pixels is controlled through these minute particles which are actually called twisted nematic phase liquid crystals.

 

Transmissive Film Types
Transmissive Film Types

They are called so because they appear twisted in their original state and they untwist as soon as an electronic charge is applied on them. Each sub-pixel has its own twisted crystal. If the electronic charge applied is very small, the liquid crystal will untwist only partially. Thus by untwisting and twisting the different crystals at different charges, almost all the colors in the spectrum can be produced.

 

Most of the LCD screens that are used for high-end applications can be called transmissive because the light source is placed behind the screen. The light source is mostly a fluorescent tube connected to a light guide that sends the light forward onto the LCD display. The light that reaches the LCD display may be scrambled. They have to be aligned with the rows of the twisted liquid crystals. This work is done by a polarizer.  The rest of the working has already been explained in detail.

The only work left to do is to add the transmissive film to the backlight area of the LCD system or onto the display screen.

Transmissive Film – Different Types

3M – The creators of transmissive films designed many types of the product which can be used alone or can be combined together within the same product to enhance the performance of the LCD display.

In order to increase the brightness of the film, they used two different methods.

The first method includes a single sheet of polymer imprinted with a prismatic surface pattern. The pattern looks like a series of triangles pointing out from the flat film surface. The light will be started by the backlight and will fit the prism in the film first. From there it will be redirected to the viewer.

If these prisms were not used most of the light from the backlight would have gone wasted. Thus, the film helps in redirecting all the light to the viewer thus increasing the brightness of the image. If there is any excess light it is made to reabsorb by the back panel of the display.

If the combination method is used, a second transmissive film is needed and thus will be called dual brightness enhancement film. The film is not only mounted with prisms, but also fitted with an extra reflective sheet. Thus sheet will help in capturing the lights that does not hit the prism at the exact angle.

Sometimes glares can be produced by the screen and this can be reduced by placing anti-reflection transmissive films on the surface of the LCD display. This anti-reflective coating consists of at least 4 layers of film. The first layer of film will help in wiping the fingerprints that may occur due to contact. This process is now applicable in most mobile phones and computers. The second coating is used to protect the screen from glares by reflecting the light at multiple angles. The third coating is used as an anti-scratch layer. The fourth coating is an adhesive that allows the film to be easily removed and replaced in case of excessive scratches or other damage.

The company has also designed special light control films which has microlouvers that keeps the images secure from people who try to sneak from the side of the screen.

 

 

 

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