2013年8月24日星期六

LCD CRT reason out

The mid-1990s, along with the LCD technology matures, liquid crystal display (LCD) as a new display device is also beginning to the market. When the LCD is hand-picked successor to CRT, the user is also devoted more attention to its attention, and also have devoted more enthusiasm and expectations. At the same time, about the shortcomings and drawbacks of lcm module began unrestricted been repeated, which is even let some users began to LCD expressed disdain and dissatisfaction. Coupled with the high price, it seems that in addition to light and environmentally friendly LCD outside, in other places, have no merit:

High response time, and you will have no interest in the game will become

Garbage general color, not to mention the plot is also reluctance to see photos

Life, a period of time the screen will be cast, brightness sharp decline

Contrast, in front of the CRT is simply not worth mentioning

Viewing angle, eyes slightly deflected

These inherent flaws LCD also aroused much controversy, but we need to see clearly, with the advances in technology, these defects are also the long fade out of our sight. Moreover, LCD is more active in the market expansion of the CRT. Past shortcomings and even become LCD comeback killer.

Gray from faster response time, more superior than CRT color performance, close to the limit of the viewing angle and higher contrast, brightness, we take a look at the specific COG LCD Module is how to CRT as deadly!

What advocates locking 19-inch LCD computer

Higher prices also equipped with high-quality

According to Sina an LCD display on the survey results show that more than 1.01 million ballots 82.4% chose the much more expensive than CRT monitors LCD monitors. People hoping for LCD computer psychology is evident.

Analysts believe that if the 15-inch QVGA lcd computer rage is the inevitable demand for consumer health, consumer comfort pursuit spawned a 17-inch LCD PC's popularity, so now the majority of users of visual desire, is bound to 19 inch LCD into the PC market center stage.

19-inch LCD computer text processing is no longer just stay in this level, in the aspect of today's broadband, digital clusters in the world, the computer's multimedia processing capabilities have become increasingly demanding. "A computer can easily and quickly dump a variety of digital devices in the pictures, videos and personalized editing; whether it has a mass of digital throughput, allow consumers freedom to exchange data; whether facilitate contacts, high-speed a variety of audio and video data download and transfer; and, ultimately, whether a customer through a computer interface, to bring consumers a more pleasant shopping experience, will become a 19-inch LCD computer consumers consider the new standard. "experts said," Based on this , including a display area, viewing angle, resolution, or even outside of fashion elements, etc. factors, determines the Graphic LCD Display computer is to 19 inches to the era of rapidly moving into the mainstream. "

2013年8月19日星期一

Organic thin film deposition process

OLED device in a high vacuum deposition chamber plurality of organic material film, the film quality is related to the quality and life of the device key. In the vacuum chamber has a plurality of heating boat evaporation sources and the corresponding thickness monitoring system, graphic lcd 128x64 ITO glass substrate fixing means, and the metal mask means (Mask). A relatively high vapor pressure organic materials, the evaporation temperature at 100-500 ℃ between, on their characteristics:
1, high vapor pressure (150-450 ℃).
2, easy to decompose under high temperature conditions, volatility.
3, good thermal conductivity foam state.
Depositing an organic material film in the evaporator, the evaporation rate is controlled lose 3-5Å / s, so that the substrate of Φ60 mm film uniformity range of up to 350Å ± 25Å. Heating the boat with good thermal conductivity, easy to control the evaporation rate. Common heating molybdenum boat and tantalum metal heating boat, in order to make more uniform heating, plus quartz boat cover, that the heating be buffered. During the vapor deposition of organic material film, generally the substrate kept at room temperature, to prevent damage to the organic material film temperature, evaporation rate should not too fast or too slow, uneven thickness of the film is too thick. Evaporation of a variety of materials were carried out in several vacuum chamber, to prevent cross-contamination. The production of the color OLED device, comprising an organic dopant material film formation,Lcd display modules to take dopant material with the matrix material of the evaporation process, the general control of dopant materials 0.5-2% (of the number of moles of the matrix material ), required in the control matrix material and evaporation to the strict control of the dopant concentration in the matrix material.

Organic material deposition FAQ

A) the effective use of materials, low
Effective options currently available to manufacturers is very limited, the system designed to be extremely efficient use of expensive organic material and the dopant; Character LCD Display present utilization is generally lower than 10% or less, full-color lower utilization of the production process.
B) dopant (Dopant) is difficult to accurately control the concentration of
With dopant of 0.5 to 1% low dispersion rates, the result of the system, and temperature control, and the physical and chemical properties of the substance itself, such that the concentration ratio is not easy to control, and the concentration of the dopant is an important factor in the device structure, which makes the production process requires precision and maneuverability more difficult.
C) deposition rate instability
Deposition material purity and temperature control system approach led to deposition rate instability.
D) the coating uniformity of the substrate is not
This is mainly because the evaporation source and the heating boat design lack of specificity of the organic material.
E) contamination of the vacuum chamber
Because the material utilization is poor, lcd graphic display so causing a great part of the material may stick to the walls and other parts and become dust sources that affect the manufacturing yield of the device. For deposition coating uniformity enough, the Japanese VieetechJapan company provides a solution to the problem (see below), it is through the narrow mouth wide bottom and large capacity PBN crucible, providing an R & D and production applications loaded on organic material of the device. In particular, it is designed for organic materials Thermoball particles, poor thermal conductivity of organic materials can solve problem of low utilization and materials; with two-stage heating and temperature measurement, PID temperature control system, can be done in a timely manner and to achieve accurate temperature feedback Temperature differences within ± 0.1 ℃, can stabilize the evaporation rate; other special dopant DopantInsert and PID temperature control system, so that 0.5 to 1% of the proportion of constant and stable dopant.

2013年8月18日星期日

Cleanroom technology applications in several hot issues currently

I. Introduction
Cleanroom air velocity / ACH, has been a concern in cleanroom design issues, with the clean room to increase pollution control results and final stage filter efficiency, etc., on the relevant norms, guidelines and other recommendations made or reference values ​​are conservative, there are many discussions; FFU in the application of the feared noise, damage repair and other issues have been resolved in practice, with the continuous improvement of FFU, FFU on whether to adopt the return air system is also a Hot: Suspended molecular contamination (AMC) control in the microelectronics and IC industry has been growing on the agenda, attention. The following cases were on these issues as summarized and analyzed.

Two. Airflow velocity
2.1 For recommended applications or reference values
Clean indoor air speed under certain cleanliness to determine, with the clean room use and other specific circumstances vary, it is not only affected by the amount of dust and indoor filter efficiency is also affected by other factors, in terms of industrial clean rooms, cleanliness and choices affect flow rate of the main factors are:
(1) indoor sources: building components, the number of personnel and operational activities, process equipment, process materials and processing technology itself, are all dust sources of release, according to the specific circumstances vary, vary greatly;
(2) indoor air flow pattern and distribution: unidirectional flow requires uniform and equal flow lines, but will be subject to changes in process equipment and personnel arrangement and location of activities such as the formation of local vortex interference; rather than unidirectional flow requires sufficient mixing, Avoid dead ends and temperature stratification;
(3) purification time (recovery time) control requirements: clean room or accidental releases of pollutants into the air or gas flow during normal operation is interrupted or intermittent convection currents or other movement of persons and equipment will result in the deterioration of cleanliness , return to the original time to determine the cleanliness of the gas flow velocity purification; the purification time control requirements depend on this time frame (lower cleanliness deterioration), the product of the quality and yield of the production capacity of impact;
(4) the final stage of the filter efficiency: COG LCD Module in a certain amount of dust indoors under high efficiency filters can be used to reduce the flow rate; energy should be considered as a high efficiency filters and reduce the flow rate, or a lower efficiency filter and the higher flow rate, in order to the product flow and least resistance;
(5) economic considerations: excessive air velocity resulting in an increase in investment and operating costs, the appropriate air velocity above factors reasonably comprehensive, too often unnecessary, does not necessarily have an effect;
(6) low demand for cleanliness cleanroom, sometimes ventilation frequency depends on the indoor heat requirements.
These factors are difficult to quantify, can only be analyzed and compared and estimates. Therefore, in engineering applications, for cleanroom air velocity tends to refer to the relevant norms, OLED Display Module guidelines and other recommendations or reference value, and then the specific circumstances of the estimated impact of the above factors were determined after comprehensive consideration.
Air velocity for unidirectional flow clean room; non-unidirectional flow clean room ventilation frequency is preferred because it is difficult to measure accurately airflow velocity; also littered with late-stage filtration rate to reflect, and can be used for various types of air flow clean room, generally covered with 100% relative to the flow rate of 0.5m / s (100fpm), 25% relative to 0.125m / s (25fpm). Current relevant norms, guidelines and other recommendations or reference values ​​are shown in Table 1.
Note: 1, ISO14644-4 for the air velocity / ACH is clear as reference materials listed in the table only for microelectronics and IC factories; right column ISO5 only pharmaceutical grade air velocity> 0.2m / s, right ISO6 ~ 8 级 Jiewei lists reference values.
2, (M) refers to the mixed flow, N refers to the non-unidirectional flow; * refers to the isolation of pollution has taken effective measures to clean areas.

Component parts of FFU control unit

FFU control can be broadly divided multi-gear switching, continuous adjustment, computer control, such as several, but the functions are single control, zoning control, alarm, TFT Lcd Modules running status display.

But what causes FFU in such a long time has not been widely applied? There are three issues dominate.

First: the noise problem. You can think about at the time of the production process level, together with the noise of thousands of wind turbines would be?

Second: the pressure balance. To a large static pressure box, each with a different corner of the fan is able to get a balanced pressure, which at the time also can not be guaranteed.

Third: maintenance issues. FFU itself cost is relatively high, if it can not guarantee the life of the motor, then replace will bring additional investments. These are caused when companies do not choose to use FFU of the main reasons.
With the development of technology, these problems become easily.

One, first reduce the fan noise itself, character oled plus the unique duct design, improved efficiency of the fan, but also greatly reduces the noise

Second, the development of computers, advanced computer control system to solve the high-volume FFU pressure imbalance in the

Third, raise the level of the production process, extending the life of the fan; German EBM-quality centrifugal fan with long life, maintenance, small vibration and other features, the working life of 50,000 hours or more.

2013年8月17日星期六

Antistatic agent in the world will have a wide range of applications

Antistatic agent market in North America is expected to 2004 years ago, the average annual growth rate of about 4%, to use point of view, most of the use of electronic appliances and on food packaging materials. The terms of the types from the antistatic agent, ethylamine class multi-use polyolefin, as electronic equipment packaging; while quaternary ammonium compounds are often used in PVC, such as industrial conveyor belts, disk packaging and bottles, etc.; fatty acid esters are more use of internal antistatic polyolefin use. European antistatic agent market will have an estimated annual growth rate of 2.5%, on purpose, mainly used in polystyrene, ABS and other styrenic polymer processing, due to add antistatic agent usually has a lubricating efficacy, it is sometimes difficult to distinguish with a lubricant. In Japan, an antistatic agent mainly of 0.1% to 0.2% of the concentration of mixed plastic being, as accurate as the mixing amount of the product on the type of polymer, wherein the polypropylene is the most frequently used products antistatic agent , followed by PVC and ABS. Antistatic agents throughout the Japanese usage rate is expected in 2003 nonionic / cationic antistatic agent used about 5,000 tons, the future will also be about 1% growth rate continues to grow.

The terms of the types of antistatic agents, polymer-type antistatic agent is the most promising permanent products, particularly the use in precision machinery is the growth of popular expectations. This is due to household appliances, electronic equipment used by the electronic circuit, when the electrostatic accumulation is excessive, Character LCD Modules poor contact may occur the situation, hence, have to prevent excessive accumulation of static electricity in this high-performance anti-
Static agent needs to be quite optimistic about the future. But so far the use of more surfactant adsorbed on the plastic surface moisture in the air to produce the effect of preventing static electricity, but because of vaporization, surface cleaning and other reasons, often making antistatic effect disappears or is contaminated, then the high dependence on humidity, in the case of drying effect is poor, so non-surfactant polymer products become better product.

Molding a polymeric antistatic agent is dispersed in the resin play a fixed effect, OLED Display and the low-molecular type (surfactant system), compared, and show a direct effect after molding, is not volatile, will not be affected by exposure contamination after cleaning effect is not reduced, etc., but the drawback is that only low-molecular type antistatic agent than the added quantity.

Currently polymeric permanent antistatic agent, compared with a surfactant system, it is still high-priced products, the manufacturers themselves without a permanent antistatic agent technology, inevitable costs will be relatively enhanced. At present, because of both the price, there are still considerable differences, there is currently a permanent antistatic agent penetration is still low, but the future along with the IT market needs and future expansion of the market, as well as other incentives under falling prices, have helped in the product market expansion.

Kind of SXL type cleanroom testing methods

SXL-type device is a clean room with air unidirectional flow (horizontal parallel flow) for laminar flow filtration, and by multi-stage purification, and then purified by the air supply unit air to the work area, so repeated high cycle work cleanliness cleanroom. SXL-type clean room is also equipped with FL-1-type air shower a desk, air shower installed in the clean room at the entrance, the operator must enter the clean room work through the air shower air shower. Air shower when contaminated air through the middle and high efficiency air filters, filtered clean air through the vents blowing tangential direction at high speed rotation of the human body, will be attached to blow off the dust on the clothes.
The clean room area is 13m3; cleanliness level is 100 (≥ 0.5μ total number of particles ≤ 3.5 粒 / L; total air volume ≈ 6000m3 / h, fresh air, 5%; workspace sectional average wind speed ≥ 0.35 m / s; ventilation frequency about 180 times / h; interior pressure ≥ 0.5 mm water column; noise <70 dB (A building); mains power is FL-1 type Airshower 10.1kW, 380V, DY- a type of air purification unit 1kW, 380V, 380V and 220V lighting and electrical outlets, etc. cleanroom wind shower circuit by controlling the electrical box, electrical box and is equipped with 450V 75A ammeter and voltmeter each one due to the device has a clean high, sealed, rigid, lightweight and beautiful, easy to dust, but in a relatively short period of time into a higher level of clean working environment, it is widely used in electronics, precision instruments, meters, medical and requirements of the various air clean and high production sites; also commonly used in quality control, health and epidemic prevention, hospitals and other authorities require a high degree of sterile air cleaner room, operating room.
Since the device's power supply power is larger, therefore, will be in use should be regularly current, voltage meter to send measurement department test, and note that the device is working Never overload of work, should always observe the operating status of the device when the electrical control box current, voltage meter indicated current, TFT Lcd Modules voltage and the actual use of current, voltage is consistent, the use of larger and current ammeter indicated current is very small, and you should immediately stop using the ammeter measurement department to send verification and maintenance. Also note that wind leaching room clean room cleaning, before the experiment, after dilution with 5% Lysol wipes filtered liquid air, return air purification unit, the device wall, work surfaces and Airshower filters walls and outlet, the filter cleaning unit should always be removed to clean, purify the air supply unit in order to ensure normal operation. Also, frequently clean indoor air cleanliness testing, the test requires some instruments, such as the level of cleanliness (clean indoor air dust concentration) required particle counter measurement; sectional average wind speed required heat
Ball anemometer to measure; interior pressure required tilting micro-manometer measurement; noise measurement required precision sound level meter and so on. Press the test method for measurement of the clean room, the test results are accurate, but because of this test method requires more equipment, and the use of equipment units are generally impossible to have this test condition, it is not possible according to the above method Clean room for testing. So, how do people use the clean room air cleanliness know what? Graphic LCD Module How a human right cleanroom contamination? How to make test results with true, accurate it? Here's a clean indoor air by precipitating bacterial tests to the test results to determine the cleanroom easy way. This method - by natural sedimentation sedimentation principle microorganisms collected particles in the air under high pressure to the glass plate in bacteria, adding 45 ℃ temperature nutrient agar medium, mixed core cooling, after some time under suitable conditions Reproduction allowed to count colonies visible to the colony plate clean environment to determine the number of live microorganisms, and in order to assess the clean room dust concentration.

2013年8月8日星期四

Dot-matrix graphic LCD module

This module is a module matrix, which matrix is ​​characterized by continuous pixels arranged in rows and columns are not arranged in an empty compartment. So you can show a continuous, full graphics. Since it is also a XY matrix pixel composition, so in addition to display graphics, but also can display characters.

1 row, column-driven
This is a dedicated controller to the external module, which module is only fitted with a common row, column drivers, which drive the pixel is actually only a general drive output terminal, and the input terminal to only four data input of the following , shift signal input terminal, the latch input terminal, the AC signal input terminal, etc., such as HD44100, IID66100 so on. Such modules must be an external control circuit, such as HD61830, SEDl330 etc. can connect with computer. The largest number of species of the module, the most common. Although the need to use self-made controller, but it also gives customers left a different controller can choose freely.

2 rows, columns driver - controlled
This is a direct interface with the computer, the computer directly controls the drive depend on the module. Such modules used in the column driver with I / O bus data interface module can be directly linked to the computer's bus, eliminating the need for dedicated controller, so the whole system cost reduction benefits. For the small number of pixels, the machine features small, for computer software programming and very familiar user very suitable. But it will take some of the resources on your system.

3 rows, columns, control type
This is a built-in controller type dot matrix graphics module. Also the more popular type. This module is equipped with not only the first category, such as row and column drivers, but also like the T6963C assembly of dedicated controller. This controller is a liquid crystal driver and a computer interface, which in the most simple way controlled by the computer, the computer receives a variety of information and feedback, through their independent information processing to achieve the display buffer management, well provided to the driver needs of the various signals, pulse, manipulate the lcm module of the drive to implement the module function. This controller has its own set of special instructions, and have their own character generator CGROM. Users must be familiar with the detailed specification of this controller can be summarized as. This module allows users to get rid of the controller design, processing, production and other series of work, and also allows the computer to avoid the cumbersome controls on the monitor, saving.

Dot matrix character LCD module

It is composed of dot matrix character lcd module and a dedicated row, column drivers, controllers and necessary fittings, structural parts assembled, and can display numbers and Latin characters. The module itself has character dot matrix character generator, display capacity, feature-rich. Usually this kind of module can also be displayed at least 8 a row or 16 l or more lines of characters. The lattice arrangement of this module is 5 × 7,5 × 8, or 5 × 11 array of pixels arranged in a bundle consisting of. mini lcd module  Each 1-bit, a bit between each interval between each line has a line interval, it can not display graphics, the specifications are as follows:
 8 a row; 2 lines
16 a line; 2 lines; 4 lines
20 a line; 2 lines; 4 lines
24 a line; 2 lines; 4 lines
32 a line; 2 lines; 4 lines
40 a line; 2 lines; 4 lines
Usually in the module control, the drive has been cured good 192 characters character font libraries CGROM, but also has to create a dedicated user-defined character RAM CGRAM, allows users to create 8 5 × 8 dot matrix characters.

2013年8月7日星期三

LCD dynamic driving method

The display is a liquid crystal display pixel due to the electric field is applied, the electric field around the display pixel electrodes on the two potential signal synthesis. Since DC electric field tends to reduce the life of the liquid crystal, therefore, generally only a very small DC component to establish an alternating electric field. DC component is typically less than 50mV. Driving the liquid crystal display is applied to the liquid crystal display by adjusting the electrode potential on the phase of the signal, the peak, frequency, etc. to establish a driving electric field in order to achieve display.
Liquid crystal display driving method are: static drive, dynamic driving method, dual drive method. This article will discuss the most widely used method to illustrate the dynamic drive.
Dynamic drive method
When the pixel Graphic LCD Display when there are many, such as dot matrix, in order to save huge hardware driver circuit, liquid crystal display production and arrangement of the electrodes do processing, the implementation of the matrix structure: that is, the level of a set of display pixel electrodes are connected back together leads, called row electrode; the vertical display pixel segment electrodes are connected together leads, called column electrodes. Each pixel on the display bits uniquely determined by their ranks. The dynamic driving method of a liquid crystal display is cyclically to the row selection pulses applied to the electrodes, and to all of the column electrodes in response to selection or non-selection with a driving pulse, in order to achieve all of the pixels of a row of display. This scan is progressive sequence, the cycle is very short, making the COG LCD Display showing a stable image.
Each line in a frame is equal to the selection time. Assuming a number of scanning lines is N, the scan time is 1, then the row selection time is occupied with a time of 1 / N. This is the liquid crystal display driver duty factor, also known as the duty cycle.

With memory interface, LCD display module

Dot-matrix LCD interface is simple, can be graphically display raster or a variety of information, so a variety of electronic design has been widely used. However, its interface must follow certain hardware and timing specifications, depending on the liquid crystal driver, may need to issue different commands to control to display the data. And execution of the command takes some time, a large number of real-time data in the system in the case, if the direct control of the liquid crystal display, may consume too much time, thus affecting the data processing. Therefore, as a need to use different COG LCD Module, which require software changes. To solve these problems, the paper proposes use of the memory interface LCD module, the existing dot-matrix LCD screen attached an MCU (Micro-Controller Unit microprocessor) and related devices, the use of memory with an external controller interface, thus solve a unified interface and display speed problems.
We know that the human eye phenomenon of persistence of vision, change every 0.1 seconds within the image appears to be a considered continuous, and only 0.1 seconds of changing images difficult to detect the human eye. According to this physical phenomenon, we use an external memory controller interface design a LCD interface module, the external controller to display the data is written directly interface to memory, depending on the interface refresh LCD display. Refresh rate more than 10 times per second, you can achieve continuous display purposes. Of course, the higher the refresh rate of the human eye image change can feel more continuous and smooth.
Wen proposed lcd module using memory and an external controller to interface with unified interface specification. External controller to display the contents of the liquid crystal display module directly into the display memory interface can be realized, not directly complicated and time-consuming matrix LCD control processing operations, is conducive to the controller for real-time processing of large amounts of data. There are currently a large color LCD screen uses a similar program, but expensive. For general applications, this paper presents the LCD module is highly versatile, and increased hardware costs less than buying a single dot matrix LCD 20%, it can be widely applied.