How hologram make?

Background

A hologram is a flat surface that, under proper illumination, appears to contain a three-dimensional image. A hologram may also project a three-dimensional image into the air—a lifelike image that can be photographed although it cannot be touched. Because they cannot be copied by ordinary means, holograms are widely used to prevent counterfeiting of documents such as credit cards, driver’s licenses, and admission tickets. The word hologram comes from the Greek roots holos meaning whole and gramma meaning message. The process of making a hologram is called holography. When a hologram is made, light from a laser records an image of the desired object on film or a photographic plate.

There are basically two types of holograms. A reflection hologram is viewed when lit from the front, while a transmission hologram is viewed by shining a light through it from the back side. An embossed hologram is made by backing a transmission hologram with a mirror-like substance, which allows it to be viewed when lit from the front. Holograms can also be made that show moving objects; these sequences, called stereograms, are typically three to 20 seconds long.

Although a hologram is a visual image of a physical object, it is quite different from a photograph. For instance, when an object is photographed, each portion of the photo contains an image of the corresponding portion of the original object. Each section of a hologram, however, contains a complete image of the original object, viewed from a vantage point that corresponds to the section’s position on the hologram. Thus, if the transparent plate containing a transmission hologram is broken, each piece will still be able to project the entire image, albeit from a different point of view. Using a piece from near the top of the holographic plate will produce an image as seen from above, while using a piece from near the bottom of the plate will create the impression of looking upward toward the object.

Another interesting property of holograms is that they preserve the optical properties of objects such as lenses. For instance, consider making a hologram of a magnifying glass placed in front of a butterfly. When viewing the holographic image of those objects, an observer will find that the portions of the butterfly seen through the image of the magnifying glass will be enlarged.

Holographic packaging has been shown to increase the sales of certain products. Projection holograms are especially eye-catching and are used at trade shows and retail stores. They can be used to display extremely delicate or valuable objects. A classic example was an image of a diamond-adorned hand that was projected over the sidewalk outside the Cartier jewelry store in New York City in 1970. Not only did it catch the attention of people walking by it, it attracted television news crews. In fact, it was even attacked by an umbrella-wielding pedestrian who thought it was the “work of the devil.” In another instance, rather than repeatedly handling the fragile skull of the 2,300 year old Lindow Man, researchers studied its holographic image. Scotland Yard’s Forensic Science Department used this holographic image to construct a physical model of the remains of the prehistoric man. As yet another application of holography, former Chicago Bears football coach Mike Ditka displayed a holographic portrait of himself in his restaurant to create a somewhat personal image when he could not be there in person.

Holograms can be made at home by hobbyists for a modest investment in equipment. The process requires a laser and an isolation table to prevent movement of the equipment while the film is being exposed. Holograms are also produced commercially and can be reproduced in large quantities. Using stock artwork, a master hologram for mass production can be created for as little as $2,500, whereas using custom artwork can cost $5,000 to $10,000. Reproducing the image costs from 1 to 4 cents per inch (2.5 cm), depending on the volume; this represents a 40% decrease since embossed holograms were first marketed in the late 1970s. Finished holograms can be attached to other objects as pressure-sensitive labels (0.5 to 1.5 cents each) or by hot stamping (2 to 5 cents each). Once the artwork is finalized, it takes about three months to create and reproduce a batch of commercial holograms. It is estimated that more than $200 million worth of embossed holograms were manufactured in 1995.

History

The first hologram was made in 1947 by Dennis Gabor, a Hungarian-born scientist who was working at the Imperial College of London. Gabor was attempting to refine the design of an electron microscope. He devised a new technique, which he decided to test with a filtered light beam before trying it with an electron beam. Gabor made a transmission hologram by carefully filtering his light source, but the process did not become practical until technology provided a way to produce coherent light—light that consists of a single frequency and a single wavelength. Hologram production took off with the invention of the laser in 1960, as a laser generates light that is of a single color (frequency) and produces waves that travel in phase with one another.

In 1962, using a laser to replicate Gabor’s holography experiment, Emmett Leith and Juris Upatnieks of the University of Michigan produced a transmission hologram of a toy train and a bird. The image was clear and three-dimensional, but it could only be viewed by illuminating it with a laser. That same year Uri N. Denisyuk of the Soviet Union produced a reflection hologram that could be viewed with light from an ordinary bulb. A further advance came in 1968 when Stephen A. Benton created the first transmission hologram that could be viewed in ordinary light. This led to the development of embossed holograms, making it possible to mass produce holograms for common use.

Nearly a quarter century after he had made the first hologram, Gabor was awarded the Nobel Prize for Physics for this achievement in 1971. The following year, Lloyd Cross made the first recording of a moving hologram by imprinting sequential frames from ordinary moving picture film onto holographic film.

Raw Materials

Holograms made by individuals are usually exposed on very high resolution photographic film coated with a silver halide emulsion. Holograms made for mass production are exposed on a glass plate pretreated with iron oxide and then coated with photoresist. The photoresist material will chemically react to the specific wavelength of light that will be used to create the hologram. Because of their availability at a relatively low cost, helium-neon lasers are most commonly used by individuals who make their own holograms. Commercial hologram manufacturers use different laser types such as ruby, helium-cadmium, or krypton-argon ion.

After exposure, the film or photoresist plate is processed in chemical developers like those used in photography. Both nickel and silver are used to make the production masters that will be used to stamp multiple copies of the holograms onto polyester or polypropylene film. Aluminum is used to create the reflective coating on the back of embossed holograms.

Design

A three-dimensional, physical object can be used to create a hologram. The holographic image is normally the same size as the original

object. This may require construction of a detailed scale model of the actual subject in a size suitable for the holographic image. Altematively, the artwork that is to be reproduced as a hologram can be computer generated, in which case software controls the laser exposure of the image file, one pixel at a time. (Pixels are the individual dots that comprise a graphic image on a computer screen or printout.)

The Manufacturing
Process

Various manuals are available that explain to amateur holographers how to make holograms at home. The following steps describe the commercial mass production of a holographic image of an actual, three-dimensional object.

Mastering

  • 1 A laser is used to illuminate the physical object, with the reflected light falling on the photoresist plate. Simultaneously, a reference beam from the laser also falls directly on the photoresist plate. The interference patterns of these two light beams react with the photo-sensitive coating to record a holographic image of the object. Common exposure times are between one to 60 seconds. In photography, slight motion of the object or the film results in a blurred image. In holography, however, the exposed plate will be blank (contain no image at all) if during the exposure there is movement as small as one fourth the wavelength of the laser light (wavelengths of visible light range from 400 to 700 billionths of a meter).

A typical photoresist plate has a 6 in (15.24 cm) square working area; an extra half-inch (1.25 cm) of space on two edges allows the plate to be clamped into position. Because many holograms are smaller than this, several different images can be “ganged” (clustered) onto one plate, just as numerous individual photographs are exposed on one roll of film.

  • 2 The plate on which the original hologram is recorded is called the master. After being exposed, the master is processed in a chemical bath using standard photographic developers. Before proceeding with production, the master is inspected to confirm that the image has been properly recorded. Because of the chemical reactions caused by the laser and the developer on the photoresist, the developed plate’s surface resembles the surface of a phonograph record; there are about 15,000 grooves per inch (600 per cm), reaching a depth of about 0.3 microns (1 micron is a thousandth of a millimeter).

Electroforming

  • 3 The master is mounted into a jig (frame) and sprayed with silver paint to achieve good electrical conductivity. The jig is lowered into a tank along with a supply of nickel. An electric current is introduced, and the master is electroplated with nickel. The jig is removed from the tank and washed with

deionized water. The thin, nickel coating, which is called the metal master shim, is peeled off the master plate. It contains a negative image of the master hologram (the negative is actually a mirror image of the original hologram).

Using similar processes, several generations of shims are created. Those made from the metal master shim are known as “grandmothers,” and they contain positive images of the original hologram. At this stage, numerous copies of the original image are “combined” (duplicated in rows) on one shim that can be used to print multiple copies with a single impression. Successive generations of shims are known as “mothers,” “daughters,” and “stamper shims.” Because these generations alternate between negative and positive images of the original, the stamper shims are negative images that will be used during actual production runs to print the final product holograms.

Embossing

  • 4 Stamper shims are mounted in embossing machines. A roll of polyester film (or a similar material) that has been smoothed with an acrylic coating is run through the machine. Under intense heat and pressure, the shim presses the holographic image onto the film, to a depth of 25 millionths of a millimeter. The embossed film is rewound onto a roll.

Metallizing

  • 5 The roll of embossed film is loaded into a chamber from which the air is removed to create a vacuum. The chamber also contains aluminum wire, which is vaporized by heating it to 2,000°F (1,093°C). The sheet is exposed to the vaporized aluminum as it is rewound onto another roll, and in the process it becomes coated with aluminum. After being removed from the vacuum chamber, the film is treated to restore moisture lost under the hot vacuum condition. A top coating of lacquer is applied to the film to create a surface that can be imprinted with ink. The roll of film, which may be as wide as 92 in (2.3 m), is sliced into narrower rolls.

Converting

  • 6 Depending on what type of film was used and what kind of product is being made, one or more finishing steps may be done. For instance, the film may be laminated to paper board to give it strength. The film is also cut into shapes desired for the final product and may be printed with messages. Heat-sensitive or pressure-sensitive adhesive is applied to the back of holograms that will be affixed to other objects or used as stickers.

Finishing

  • 7 The holograms are either attached to other products or are counted and packaged for shipment.

The Future

Today, the most common use of holograms is in consumer products and advertising materials. There are some unusual applications too. For example, in some military aircraft, pilots can read their instruments while looking through the windshield by using a holographic display projected in front of their eyes. Automobile manufacturers are considering similar displays for their cars.

Holograms can be created without visible light. Ultraviolet, x-ray, and sound waves can all be used to create them. Microwave holography is being used in astronomy to record radio waves from deep space. Acoustical holography can look through solid objects to record images, much as ultrasound is used to generate images of a fetus within a woman’s womb. Holograms made with short waves such as x rays can create images of particles as small as molecules and atoms.

Holographic television sets may project performers into viewers’ homes within the next decade. Fiber optic communications systems will be able to transmit holographic images of people to distant homes of friends for realistic visits. Just as CD-ROM technology used optical methods to store large amounts of computer information on a relatively small disk, three-dimensional holographic data storage systems will further revolutionize storage capacities. It is estimated that this technology will store an amount of information equivalent to the contents of the Library of Congress in a space the size of a sugar cube.

Read more: http://www.madehow.com/Volume-3/Hologram.html#ixzz6EJ8cPeeZ

What is UV LED cast and cure process?

UV LED CAST CURE is a method to create microstructure (such as holographic effect, optical effect and so on)on printed film or paper through a UV LED curing process. UV LED cast cure process is a simple technical method to help our clients increase more eyes catch design on the products. Compared with traditional UV cast, DPL UV LED technology to provide better production efficiency and lower cost.

How does UV LED CAST CURE Work?

UV LED cast cure also use an embossed holographic cast film (normally it’s BOPP film) as holographic master. The different between nickel master and cast film, it’s cast film cannot provide “deep solution” hologram feature. It means most UV LED Cast cure process only be used as “decoration”.

The general process includes two nip rolls, one is called as a master cylinder on which have holographic or other microstructure feature, and the other is pressure rubber roller. When film or paper passes through these two pressure, the holographic image on the master cylinder will be cast on the surface of film or paper. The UV LED curing lamp will dry UV LED lacquer on film or paper after the casting process, so holographic or other microstructure will be on the surface as well. Compared with traditional UV cast and cure process, UV LED curing system use typical single wavelength, for example, 395nm or 385nm, which is easier pass through film if the lamp is installed on the back side of the film. Also LED curing system uses cold light source so curing temp is also lower than Traditional UV lamp. Because LED lacquer is a single wavelength so it will not be dried by visible light.

 

Ozone free UV lamp for coating equipment

What is ozone free  UV lamp?

Many finishers today are considering adding UV coating equipment to create a more attractive surface on their printing products to catch their client’s eyes. The big change challenge for them is the safety and handling issues that go along with the process after they start to use “anti-UV” cream on their face and body when they lay on the beach. So how dangerous when you use UV equipment?

Most UV/EB curing materials generally are not “hazardous waste” (toxic, corrosive, flammable, or reactive) as defined under RCRA regulations. However, as with all chemicals, contaminated materials and wastes should be disposed of in accordance with federal and local requirements. In addition, UV/EB curing materials contain little to no VOC’s and typically contain no hazardous air pollutants (HAPS) as specified by the EPA. They are not typically specified in any federal or state Community Right-to-Know list as well.

The only sideproduct of the UV lamp is Ozone Gas. It has a pungent sweet odour and is distinctive enough that concentrations well below the threshold limit value (TLV) of 0.1 ppm are still noticeable. At high enough concentrations, ozone gas and odours can cause headaches and fatigue. After repeated exposure at high concentrations, ozone can cause dryness of the upper respiratory tract, pulmonary irritation and possibly respiratory infections.

Many experts tell you that this is very simple, you only need to increase ventilation. but it is not the truth.

When the device is using a high-power suction and exhaust device, it may cause the UV lamp to open abnormally due to the low temperature.

To solve this problem, the first thing we need to understand is why the UV lamp produces ozone.

The UV curing device produces ultraviolet light having a wavelength in the range of 200 to 425 nm. Among them, when short-wave ultraviolet light below 275 nm is in contact with oxygen in the air, ozone is easily generated, which is a great source of the irritating odour. From the reaction mechanism point of view, the short-wave ultraviolet light will decompose the oxygen molecules in the air, thereby generating free oxygen. Because the positive and negative electrons carried by the free oxygen are unbalanced, it will combine with the oxygen molecules to generate ozone. These ozone often cannot be decomposed by themselves, not only floating in the air but also remaining on the surface of the printed product (the printed product is adsorptive and will retain some of the odours)

How to make an ozone free UV lamp?

On the one hand, the DPL ozone free UV lamp adopts a fully enclosed design. Even when the shutter is opened, the air cannot enter the lampshade and combine with the low-band UV light to generate ozone. On the other hand, when the UV light passes through the special filter function glass window in the lampshade, only the long wavelength UV light can be directed to the printing material, thereby preventing the short wavelength UV light from coming into contact with the air to generate ozone.

DPL ozone free UV lamp is a patented product of our company and has been certified by CE and ul to meet the safety standards of the European Union and the United States.

 

What is UV curable soft touch coating technology

What is Soft touch coating technology?

Soft touch coating technology is more and more used for packaging design. As you know, you feel different between the film or paper and your cloth when you touch them. You feel softer when you touch your cloth or textile sofa. Soft-touch or soft-feel coatings are employed to create a variety of haptic effects on plastic, paper and metal substrates. So that you feel touching a paper as a cloth.

What is the advantage of soft touch coating technology?

The answer is simple,  it will help you sell more products. Recently, California Polytechnic State Universit had a research on marketing different between soft touch designed products and traditional packaged design. Compared with traditional design, soft-touch coatings span a variety of markets including automotive interiors, small electronics, and appliances. It shows not only did customers prefer cosmetics packaged in a container with a soft touch coating versus a traditional coating, they were willing to pay a 5% price premium.

What is UV Curable soft touch coating technology?

To make soft touch coating on film or paper is typically created by crosslinking multifunctional isocyanates with polyols. This process creates hard regions from the isocyanates distributed in softer regions created by the polyols. The problem is, it also takes longer curing time when we coat these two continents. This is why we use UV curable soft touch coating technology.

What can DPL Help you on soft touch coating technology?

As one of the oldest UV LED curing technology developer in Europe, DPL has many experiences on how to design your curing process. DPL specially design  UV curing lamp for soft touch coating industry, not only provide higher UV energy output but also better uniformity. So that our system can reach high-quality request for UV Curable soft touch product. Compared with other suppliers, DPL special design UV Curing lamp for soft touch coating, provides better working lifetime as well. More detail or need technical help, welcome to call us at +45 28871021 or email to dpl@dpl.dk

 

What is High-speed UV LED ink ?

High-speed UV LED Ink is the most important fact affect your printing quality and efficiency.  Well-formulated inks ensure continued print quality, system uptime reliability, and high productivity without user intervention.

What is UV LED ink?

Compared with traditional UV ink, UV LED inks only active for typical wavelength. Because of special consideration of photoinitiators and pigments
in the ink formulation, which only matches the spectral output of
the LED lamps. These special photoinitiators absorb at a higher
wavelength as opposed to traditional photoinitiators and are
typically more expensive. The spectral output of a LED lamp to
cure UV LED inks is very narrow, 365 – 405 nm, as compared to
a UV mercury system which operates from 200 – 700 nm range.

What is UV LED Curing?

Because of the limited spectral wavelength, UV LED primarily
operates in the UV-A zone and considered to be ‘safe’ because
it is closest to visible light. However, prolonged exposure to
this energy can be dangerous. The UV-B and much of the
UV-C spectrums of light are primarily used for germicidal and
sterilization purposes. The light produced at these wavelengths are
not only harmful to microorganisms but are also dangerous to
humans and other forms of life that may come in contact with it.
These lamps should always be shielded and never viewable to
the naked eye, even though it may appear that little or no light is
emanating from the device. Exposure to these wavelengths may
cause skin cancer and temporary or permanent vision loss or
impairment.

How does high-speed UV LED ink work?

Compared with traditional UV lamp, UV LED lamp only active on typical wavelength. However,  it doesn’t mean UV LED ink need less UV energy for curing. You can see from the following picture of our UV LED Ink testing report, good DOSIS energy will help for improving curing speed and quality. Therefore, we have confidence that even use the same UV LED ink, DPL high power UV LED curing system can cure faster and better.

LED INK TESTING REPORT

Is your UV lamp safe?- Harmful ozone

Is your UV lamp safe?

In modern industry, more and more people pay attention to how to produce “safe product” with the green process.  For example, you can find more and more organic markets in our city.  Back to our  printing and coating industry, more and more people are thinking about how to reduce pollute, one of the good ways is using more green source instead of difficulty recycled material, such as in printing and coating process, use UV lamp as drying source instead of heating source, because UV light or LED light drying source can cure the ink in very short time.

Harmful Ozone

Is your UV lamp safe? I believe that you have the experience when you walk into a UV printing production in China, or when you visit a printing machine exhibition, you can smell “Rotten egg”. That is Ozone smell.

The Environmental Protection Agency (EPA) warns that although ozone in the stratosphere protects us from harmful UV radiation, low-level ozone is dangerous. Infants, children, and those with respiratory problems may be in particular danger.

How UV lamp produce Ozone?

Before we try to solve this harmful ozone problem, we need to find out how UV lamp produces ozone.  UV light includes different wavelength light from UVA to UVC. When UVC hits oxygen (O2) molecules, it produces ozone.

With our patent design of UV lamp house, DPL UV curing lamp system is an “Ozone free” system. See the following video, which will introduce you how to design an ozone-free system. https://youtu.be/da91R4fhq7M

DPL UV Lamphouse uses a closed design house construction. Therefore after you close the house, UV light will not touch outside air.Also, there is only very low-density air inside lamphouse, very low-density ozone will be produced when you just close the lamphouse, which is proofed by Denmark and European Industry. It means that our client doesn’t need to install expensive “ozone exhaust” system, their worker can work in a clean “Ozone free ” production.

 

DPL Super wide Cold UV curing lamp at 2000mm

What is Super wide UV curing Lamp?

Super wider UV curing lamp means lamp provides curing width over 1700mm.

For graphics printing and coating business, more and more clients are looking for the more efficient printing process to reduce production cost.  Therefore, our clients also need wider web printing or coating machine equipped with Super wider UV curing lamps. But super wider UV lamp is not only just wider. Compared with standard width UV lamp, super wider lamp need to consider more than the width.

DPL Pattern Lamphouse construction

DPL Super wide Cold UV curing lamp at 2000mm with specially coated reflector and our pattern design on lamp construction. For example, from the top to two side frame of lamphouse, there is UV radiation refect coating. When UV lamp is on, these coating layers will reflect light to the bottom quartz window. Quartz window has very high UV transmission, means more than 95% UV light will pass throw. In order to reduce production cost, there are many manufacturers use the cheap reflector or even don’t use specially coated UV reflector. But as you know, more than 60% light energy of UV lamp is IR. The problem of IR is to dry the solvent or water-based content inside of UV Ink or lacquer. The Result is the outside of ink is dry, but inside ink cannot be dried. Because the dried top side is too hard to go throw.

High-efficiency  chilling channel

Inside of lamphouse, DPL high-efficiency chilling channel can cool down lamphouse frame by automatic controlled chilling water. The chilling control sensor can automatically increase or decrease water flow.

 

DPL Super wider curing Lamps are designed for super wide printing and coating machine. Lamp carry on DPL’s focus on cold curing temperature and uniformity, which is suitable for super wide touch screen or printed electrics process.

 

How to design Cold UV curing Lamp?

What is Cold UV curing system?

Before we start to explain what is cold UV curing system, we have to explain some basic knowledge of UV curing technology.

How does UV lamp work?

According to the different application, there are several types of UV Lamp.  For example, we can see many UV lamps when we visit emergency or operating room in hospitals. They are UVC lamp, which uses for disinfecting. UVC means the light wavelength from 100-280nm.  For graphics printing and coating industry, we use kinds of Gas-discharge UV lamps or UV LED lamp. Gas-discharge lamps are a family of artificial light sources that generate light by sending an electric discharge through an ionized gas. For UV LED lamp, we will introduce later. 

What is DPL cold UV curing system?

As you know, UV lamp output includes 60% IR energy, a normal metal reflector reflects IR energy out of the lamp head/house, and heat up the touch temperature between your base material and lamp head. Every DPL lamp head/house use specially coated reflectors from the top frame to the two sides frame. These reflectors can absorb 90% IR from your lamp and transfer to the chilling system. Therefore,  the surface temperature of your printing material is the only 5-10C degree higher than your environment temp.

What is the advantage of Cold UV curing system?

Besides of which we mentioned before, reduce UV curing temperature can help improving printing quality. Cold UV curing temperature can also help improving UV lamp bulb ‘s working lifetime. By our pattern design lamphouse, the general lifetime of our UV lamp bulb is over 2000 to 3000hours. On the other way, the lower curing temperature is good for curing  UV lacquer on the thermal sensitive material. For example, even for printing base film as PET film, lower curing temperature will help improving printing accuracy.

More information, welcome to watch our video.