Application of nano-sensor technology in packaging and printing (4)

6, color sensor, the color of light can be expressed by wavelength, and the color of light can also represent a specific wavelength. The yellow light that the human eye can see, the wavelength is 550cm, can be seen because it appears in the form of monochromatic light. In addition, red light with a wavelength of 650 nm is yellow after mixing, and can also be seen with the naked eye. It is not necessary to determine the wavelength of light with the naked eye in the arts and other fields. It is less important whether or not it is mixed by what light, and the ultimate sense of color is what people are concerned about.

For the determination of light, wavelength is one of the most important parameters. The so-called color sensor actually uses the spectrophotometric degree of the sensor to detect the color of light according to the wavelength. In other words, it is the wavelength sensor of light. The wavelength sensor of light is also called a diffraction grating or a wavelength measuring instrument. It is composed of a high-precision beam splitter and a light-receiving element, and has a wide range of applications.

7. Biosensors Biosensors are sensors that are used to determine biologically related chemicals, most commonly enzyme and microbial sensors.

The molecular recognition sensor (cyclodextrin), as its name implies, is a sensing instrument that recognizes and quantifies molecules. The function of the biofilm is to generate the current through the special K+ ion and Na+ ion through the protein (also called ion channel) embedded in the phospholipid bilayer membrane, so as to obtain the information of nerve excitation.

Biosensors have a wide range of applications and are currently one of the most active biotech fields. The application of enzyme catalysis technology to biosensors is one of the important directions for the development of enzyme catalysis technology. The biosensor is mainly composed of three parts, as shown in Figure 8-22. The first part is the signal identification system, the second part is the signal conversion system, and the third part is the data processing and response system. Among them, the most critical signal recognition system is borne by biological enzymes and biological antibodies.

Compared with the classic sensors, these new nanosensors have the advantages of small size, high speed, high reliability, high sensitivity, high response speed, high precision, low power consumption, and low cost. These characteristics are the mainstream of next-generation sensor technology development.

Fifth, the application of nanosensors in the field of packaging and printing

Imagine that the supermarket package can be immediately notified that the food has experienced too high temperatures or has deteriorated; imagine a small, robust, automatic indicator that can constantly monitor such dangers as gas leaks, carbon monoxide, and ozone in the room. Chemical substances; envisage a simple wipe test that can tell whether the patient has streptococci, diabetes, various genetic diseases, influenza, or anemia. Imagine a simple wire inserted into the ground to tell the gardener which piece of soil is best for growing cucumber; imagine Use a simple, durable (it must be simple) exposure test so you don't have to take off all your clothes at the airport. All these possibilities are potential applications for nanosensors.

1, the application of optical sensors in packaging and printing

A very old, and somewhat more subtle, nanoscale light sensor is hidden behind the science and art of photography. In traditional silver salt photographs, photons (light energy) cause a chemical reaction between the silver ions in the emulsion on the surface of the film. The silver ions are clustered together to form nanoscale silver clusters (the simplest being actually only 4 atoms), which grow large enough to scatter and capture light and thus appear black on the surface. The principle of such basic performance of nanotechnology as scale changes is once again playing a role here.

The production of X-ray, ultraviolet and infrared films is very similar to the process requirements (these films are often made by the same company that makes the photographic film). What is needed is a simple photosensitizer. Usually these are silver based and must be able to interact with light of the appropriate wavelength. For x-rays, the wavelength is very short, and the infrared wavelength is very long. In order to adjust a Gretzler-based photosensor to respond to different colors or types of light, it is only necessary to find suitable dye molecules.

Sensor elements in the film are molecules and/or atoms, and the sensing process consists of an irreversible transition of silver atom clusters. The microphone senses sound or stress in a very different way. They consist of a diaphragm in which the diaphragm is placed and vibrates when subjected to pressure or sound waves. This is very similar to the principle of the eardrum. When an external pressure source hits the eardrum, it begins to vibrate. In fact, the villus elements in our ears act in the same manner as spin-off membranes and are implanted in vibrations caused by the external sound pressure waves of the corresponding sound, after which a complex chemical signal receiving device is activated by the vibration of the thin film. The ear is a complex multi-channel electromagnetic sensor based on molecular signals. The energy from the vibrations in the film is converted and propagated into (a technical term is "transformed") into electromagnetic signals that are transmitted to the brain. It is most suitable to detect the interference fringe using the solid-state imaging device of the image sensor. If an interferometer made of micro-optical technology is used and a semiconductor image sensor is further equipped, super-miniaturization of a two-dimensional phase sensor can be realized.

Because light sensors that convert optical imaging into electrical signals are commonly used on digital cameras, they are called image sensors. In addition to the ability to simultaneously detect the light intensity and light color, the image sensor also has a binary positioning distribution function and is a multi-function sensor.

2 Application of Nanosensors in Printing Machines

The high specific surface area, high activity, specificity, and minuteness of nanoparticles make them the most promising materials for sensor applications. The nanoparticle sensor made of nanometer material has the following characteristics: (1) high sensitivity, 10 to 100 times higher than that of a Hall device; (2) good linearity; (3) a wide range of operating temperatures and can be used in one Normal working at 195°C～+300°C; (4) Good stability, instability less than 10-8, which can replace the existing sensors in many fields, and improve the product's automatic control system to a new level Level. There are many sensors used in modern high-precision printing presses, such as automatic lift control Feida paper stack, air pump gas supply time detection, pressure detection, air gap detection, ink volume control, etc., especially in the automatic register device Has a broad application prospects. In addition, in the high-level automation of the shaftless printing press, all the functional motors are required to run synchronously. The use of nano-sensors can well ensure the synchronous operation of each motor. This is to a large extent the accuracy of the shaftless printing press.

Scientists in our country have developed nanocrystalline giant magneto-impedance materials. The nano-magnetic switches and sensors made of it have been widely used in mechanical operations and automotive industries. There are several offset printing machine manufacturers in China that use nano-magnetic switches and sensors, which have many advantages compared with the dry yellow tube test sensors and hall sensors used in the past.

The main technical performance of a nano-magnetic proximity switch commonly used in offset printing machines is described as follows:

Model: C-NAMI-CO-CZK-D, working voltage (V DC): l8-30V, action distance: ≥ 5mm, jump time: ≤ lo0 S, triggering magnetic field strength: 250mt, detection frequency response: LED ( LED) follow-up, working environment: a 2O °C ~ +80 °C.

In nanosensor research, as early as in 1980, Matsushita Electric Industrial Co., Ltd. opened tin oxide ultra-fine particle sensors and optical sensors, China's research in this area is still in its infancy. With the further in-depth research of nano-materials technology, it is bound to bring about rapid changes both in traditional printing and electrophotographic copying, inkjet printing, and laser printing. Nanotechnology will also be applied to the drive. Such as tiny micro-motor systems (MEMS). Microelectronics technology can place lo0 million micromachines on a silicon wafer, each with an electronic control system. The Texas company in the US has used MEMS technology to develop chips for displaying video images. Millions of cars are equipped with a sensor-transmission device that is as thin as the hair, and when it feels a shock, it immediately releases the airbag. With this device installed on the press, pressure, speed, position, etc. can be precisely controlled. (to be continued)