Who produces domestic LCD displays. POS materials. Design bureau of POS cardboard displays

The MELT company is one of the few Russian electronics manufacturers whose products meet world standards. Now the company's product line includes several hundred LCD indicators that are not inferior to foreign analogues. At the same time, domestic displays have a record wide range of operating temperatures, support various character generators and have a very competitive price.

The presence in the title of the article of the name of a Russian electronics manufacturer can direct thoughts towards the current problem of import substitution. A lot is said and written about replacing foreign goods, including electronics, with products from domestic manufacturers. However, in reality everything is not so simple.

Russian electronics can compete with imported analogues only in some narrow areas. For this reason, every successful domestic electronics manufacturer is a source of pride. One of them is the MELT company.

MELT company was founded in 1995. Initially, its main activity was the development and production of Caller ID (automatic number identification) boards. Even then, the basic principle of the company’s work was self-reliance - in-house development and production. Thanks to an experienced development team and the purchase of modern equipment, a full cycle of creating electronic devices was organized: design, assembly, quality control, testing and sales. These traditions have been preserved and enhanced. At the moment, MELT has the ability to develop and produce printed circuit boards, assemble electronic components using modern installation technologies (SMT, COB, TAB).

The stable quality of MELT products is well known not only to Russian consumers, but also to their colleagues from the CIS countries, Europe and the Middle East. In order not to be unfounded, we can list the regular partners of the MELT company: Svyaz Engineering CJSC, METTEM-Svetotekhnika CJSC, METTEM-Technology CJSC, PC Medical Equipment OJSC, Space Research Institute of the Russian Academy of Sciences, NPP ITELMA LLC ", OJSC Saransk Instrument-Making Plant, OJSC Stavropol Radio Plant "SIGNAL", Joint Institute for Nuclear Research and many others.

Currently, the company is engaged in the development and production of printed circuit boards, LCD indicators, power supplies, and LED bars.

Among the company's products, LCD indicators are worth special mention. MELT character-synthesizing and graphic LCD displays are developed and produced at the company’s own facilities. They have proven themselves to be the best and enjoy well-deserved respect from both large electronics manufacturers and non-professional electronics enthusiasts.

Among the advantages of MELT LCD indicators are the use of the most modern production technologies, excellent contrast, a huge selection of models, support for Russian/English/Belarusian/Ukrainian/Kazakh character generators, a wide operating temperature range, low price and maximum availability.

MELT: modern technologies for creating LCD panels

The MELT company uses LCD glass (LCD panels) for character-synthesizing and graphic LCD indicators using two of the most modern technologies: STN (Super Twisted Nematic) and FSTN (Film Super Twisted Nematic). Each technology has positive and negative image versions (STN Positive/Negative and FSTN Positive/Negative). In addition, versions using indirect light or LED lighting are available.

One of the most important advantages of MELT LCD panels is their record wide operating temperature range. Most LCD lines have models that can operate at temperatures of -30...80°C, and the storage temperature range for them is -45...80°C.

Another advantage of MELT LCD panels is their high contrast. According to this indicator, they are superior to their foreign competitors.

It is worth noting that glass is only part of the technological cycle for creating LCD screens. The quality of the LCD screen directly depends on the technologies used for mounting electronic components. Here the MELT company has a special reason to be proud.

Wiring quality is the key to the quality of LCD displays

Obviously, one LCD panel is not enough to create a display. A controller, power supply system, and printed circuit board are required. In addition, it is important to ensure high-quality installation of elements on the board.

MELT has an experienced team of engineers who are able to independently develop circuit design and display circuit board. At the same time, for most modules, LCD controllers from the domestic company OJSC ANGSTREM are used.

Our own ultra-modern installation production is the pride of the company. Currently, MELT has equipment to perform high-performance installation using SMT and COB technologies.

COB (Chip On Board) technology involves mounting unpackaged microcircuit chips directly onto the board. COB has advantages over using standard packaged chips.

a) example of manual installation of open-frame
microcircuits

c) filling with compound the installed
unpackaged microcircuits

Rice. 1. Stages of mounting LCD controller chips using COB technology

As mentioned above, COB is used for fast-acting components. It is this technology that is used to install LCD controllers in MELT LCD displays (Figure 1). MELT equipment allows you to perform the full installation cycle on your own: installation and positioning (Figure 1a), welding of leads (Figure 1b), installation quality control, sealing the crystal with a compound (Figure 1c).

MELT COB equipment has the following characteristics:

number of boiled pins: up to 10,000;
conductor width: from 90 µm;
gap between conductors: from 90 microns.

In addition to the specialized technologies listed above, MELT has equipment from leading Japanese and European manufacturers (YAMAHA, Assembleon, Ersa, Dek and others) for traditional SMT installation and installation of lead components. Flexibility for assembling small and large series of printed circuit boards is achieved through the presence of two surface mount lines and a through-hole mount line.

The first surface mounting line is designed for automatic assembly of large series of printed circuit assemblies. Its maximum productivity is up to 20,000 components per hour. The line includes the following equipment:

automatic PCB loader Nutek NTM 710 EL;
DEK ELA automatic solder paste printer;
convection oven ERSA HotFLow 5;
automatic unloader of printed circuit boards Nutec NTM 710 EM 2;

The second surface mounting line is designed for assembling small and medium-sized series of printed circuit assemblies. It is this line that allows the installation of lead-free components. The line's capacity is also up to 20,000 components per hour. It includes the following equipment:

semi-automatic solder paste printer DEK 248;
multifunctional machine for arranging components YAMAHA YS12F;
convection oven BTU Pyramax 98A;
automatic PCB unloader Nutec NTM 710 EM 2.

The through installation line includes:

installation of dynamic wave soldering KIRSTEN-K5360P;
installation of jet cleaning of printed circuit boards TRIMAX.

After installation, the blocks undergo quality control using the TRION-2000 3D optical installation.

To test components at different temperatures and humidity, the ESPEC SH-661 heat/cold/humidity climatic chamber is used.

Thus, MELT is capable of not only developing, but also producing LCD displays in-house while maintaining the highest quality manufacturing.

Eight reasons to choose MELT LCD display

There is a fairly wide range of manufacturers of LCD panels and displays. For this reason, it is especially pleasant to know that the MELT company is not lost against their background. Moreover, in a number of parameters, MELT products are superior to foreign analogues.

Let's name eight reasons why you should choose MELT LCD displays.

Firstly, excellent contrast performance, not inferior to competitors. This is achieved through the use of the latest FSTN and STN technologies.

Secondly, the widest selection of models (more than 600 representatives): character-synthesizing and graphic; with positive and negative display; with different backlight colors (amber, yellow-green, red, blue, white); with supply voltage 2.8/3.0/3.3/5 V; with different formats and resolutions; with and without temperature compensation.

Even the brand name of the displays, consisting of nine positions, speaks about the variety of models (Table 1).

Table 1. Naming of MELT LCD displays

M.T.	-16S24	-1	Y	L	G	T	-3V0	-T
1	2	3	4	5	6	7	8	9
Company (MELT)	Series	Work/Storage, °C	LCD panel type	Backlight type	Backlight color	Orientation	Upit	Thermal compensation
		1: 0…50/-10…60	T: TN positive	L: – LED	A: amber	(empty): 6 hours	2V8 – 2.8 V	(blank): no
		1: 0…50/-10…60	N: TN negative		G: yellow-green	T: for 12 hours	3V0 – 3.0 V	T: yes
		2: -20…70/-30…80	M: HTN positive		R: red		3V3 – 3.3 V
		2: -20…70/-30…80	H: HTN negative		B: blue		(blank) – 5.0 V
		3: -30…70/-40…80	Y: STN yellow positive		W: white
		3: -30…70/-40…80	G: STN gray positive		(empty): option
		4: -40…80/-40…90	B: STN blue positive
		4: -40…80/-40…90	K: STN negative (blue)
		7: -10…50/-30…60	F: FSTN positive
		7: -10…50/-30…60	V: FSTN negative (black)

Thirdly, real performance at low and high temperatures. There are displays with an operating temperature range of -40...70°C. Moreover, the storage range for them is -45…80°C. And, unlike foreign analogues, these are not some specialized hard-to-find versions made to order, but serial samples.

And for custom indicators, the operating range can even reach -40...80°C.

Fourthly, MELT digital-alphabetic character-synthesizing displays have the ability to support Russian/English/Belarusian/Ukrainian/Kazakh character generators. In addition, using the 5x8 letter format makes the display of Cyrillic letters clearer and larger!

Fifthly, an additional character generator page in Win-CP1251 encoding simplifies writing programs in the Microsoft Windows environment.

Sixthly, the highest reliability and quality of MELT products.

Seventhly, availability and the ability to supply large quantities of indicators in the shortest possible time at low cost.

And the last eighth point is the possibility of ordering unique and specialized indicators with minimal production time. More details about custom LCD screens will be discussed in the final part of the article.

Let's start our review of MELT products with serial models.

Character-generating MELT LCD displays

The range of MELT alphanumeric LCD displays includes 19 series, including more than 500 models (Table 2).

Table 2. Series of alphanumeric MELT LCD displays

Name	Controller	Permission	Dimensions, mm	Visible area, mm	Symbol, mm	Backlight	Glass type	Upit, V	Trab, °C
	KB1013VG6	08x2	58x32x12.9	3×16	3.55x5.56			3; 5	-20…70; -30…70
	KB1013VG6	10x1	66x31x9.2	56×12	4.34×8.35	Yellow-green	STN Positive	5	0…50, -20…70, -30…70
	KB1013VG6	16x1	122x33x9.3	99×13	4.86×9.56	Amber, blue, yellow-green, white	FSTN Positive, FSTN Negative, STN Negative Blue, STN Positive	3; 5	-20…70; -30…70
	KB1013VG6	16x1	122x33x13.1	99×13	4.86×9.56	Amber, yellow-green, no
	KB1013VG6	16x2	85x36x13	62×19	2.95×5.55		FSTN Positive, FSTN Negative, STN Negative Blue, STN Positive
	KB1013VG6	16x2	84x44x13.0	62×19	2.95×5.55
	KB1013VG6	16x2	85x30x13.5	62×19	2.95×5.55	Amber, blue, yellow-green, white, none
	KB1013VG6	16x2	122x44x13	105.2×24	4.86×9.56	Amber, blue, yellow-green	FSTN Positive, FSTN Negative, STN Positive
	ST7070	16x2	84x44x13.0	62×19	2.95×5.55	Amber, blue, yellow-green, white	FSTN Positive, STN Positive
	KB1013VG6	16x4	87x60x13.1	62×26	2.95×4.75	Amber, blue, yellow-green, white	FSTN Positive, FSTN Negative, STN Negative Blue, STN Positive
	KB1013VG6	20x1	180x40x9.3	149×23	6.00×14.54	Amber, blue, yellow-green, white, none
	KB1013VG6	20x2	116x37x13	82×19	3.20×5.55	Amber, blue, yellow-green, red, none	FSTN Positive, STN Positive
	KB1013VG6	20x2	180x40x9.3	149×23	6.00×9.63	Amber, blue, yellow-green, white, red, none	FSTN Positive, FSTN Negative, STN Negative Blue, STN Positive	3; 5	-20…70; -30…70
	KB1013VG6	20x4	98x60x13	76×26	2.95×4.75	Amber, blue, yellow-green, white, none
	KB1013VG6	20x4	146×62.5×13	122.5×43	4.84×9.22	Amber, blue, yellow-green, white, red
	ST7070	20x4	98x60x13	76×26	2.95×4.75	Amber, blue, yellow-green, white	FSTN Positive, STN Positive	5	-20…70
	KB1013VG6	24x1	208x40x14.3	178×23	6.00×14.75	Amber, blue, yellow-green, white	FSTN Positive, FSTN Negative, STN Negative Blue, STN Positive	3; 5	-20…70; -30…70
	KB1013VG6	24x2	118x36x13.5	92.5×14.8	3.15×5.72	Amber, blue, yellow-green, white, none	FSTN Positive, FSTN Negative, STN Positive
	KB1013VG6	24x2	208x40x14.3	178×23	6.00×9.63	Amber, blue, yellow-green, white	FSTN Positive, FSTN Negative, STN Negative Blue, STN Positive

With such a variety, it is easy to choose a display with the required characteristics:

using various technologies, for example, STN Positive/Negative, FSTN Positive/Negative (Figure 2);
with different character and string formats – 08x2, 10x1, 16x1, 16x2, 16x4, 20x1, 20x2, 20x4, 24x1, 24x2;
with different backlight colors - amber, yellow-green, red, blue, white;
with different supply voltage: 3 or 5 V;
with different operating temperature ranges, including -30…70°C;
with serial (ST7070 controller) or parallel (KB1013VG6 controller) communication interface.



Rice. 2. Examples of character-synthesizing LCD indicators MELT 24 x 2

It is worth especially noting that most of the displays are built on the basis of the domestic KB1013VG6 controller produced by ANGSTREM OJSC. In terms of functionality, it is similar to the Hitachi HD44780 and Samsung KS0066 controllers.

Distinctive features of KB1013VG6 are:

wide range of supply voltages: 2.7…5.5 V;
LCD power supply range: 3.0…13 V;
high-speed communication interface: up to 2 MHz (at Upit = 5 V);
80 bytes of RAM display data (80 characters);
19840 bits of character generator ROM with the ability to program two user character pages;
64 bytes of character generator RAM.

MELT graphic LCD displays

As in the case of character-synthesizing displays, the range of graphic LCDs produced by MELT is also pleasantly surprising: 10 lines that unite more than 120 models (Table 3).

Table 3. Series of MELT graphic LCD displays

Name	Controller	Resolution	Dimensions, mm	Visible area, mm	Point size, mm	Backlight	Glass type	Thermocomp	Upit, V	Trab, °C	Tharan, °C
Name	KB145VG4	122×32	77x38x9.5	62×19	0.4×0.4	No	FSTN Positive, STN Positive	No	5	-10…60, -30…70	-10…60, -40…80
	KB145VG4	122×32	77x38x13	62×19	0.4×0.4	Amber, yellow-green, blue, white, red	FSTN Positive, FSTN Negative, STN Negative Blue, STN Positive	No	3,3; 5	-10…60, -20…70, -30…70	,-10…60, -30…80, -40…80
	KB145VG4	122×32	84x44x9.5	62×19	0.4×0.4	No	FSTN Positive, STN Positive		5	-10…60, -30…70	-10…60, -40…80
	KB145VG4	122×32	84x44x13.5	62×19	0.4×0.4	Amber, yellow-green, blue, white	FSTN Positive, FSTN Negative, STN Negative Blue, STN Positive		3,3; 5	-10…60, -20…70, -30…70	,-10…60, -30…80, -40…80
	KB145VG4	122×32	77x38x13	62×19	0.4×0.4	Amber, yellow-green	FSTN Positive		2,8	-20…70	-30…80
	KB145VG4	122×32	94x48.5x9.6	85×26	0.62×0.62		FSTN Positive, FSTN Negative, STN Negative Blue, STN Positive	No/Yes	3; 5	-20…70	-30…80
	K145VG10	128x64	93x70x13	71.7×38.7	0.44×0.44	Amber, yellow-green	FSTN Positive, FSTN Negative, STN Positive		3; 5	-20…70, -30…70	-30…80
	NT75451	128x64	69x48x12	65×34.6	0.47×0.42	Possible	FSTN Positive, STN Negative Blue, STN Positive		3,3
	K145VG10	128x64	75x52.7x8.5	60×32.6	0.4×0.4	Amber, yellow-green, blue, white, none	FSTN Positive, FSTN Negative, STN Negative Blue, STN Positive	No	3; 5
	KB145VG4	61×16	66x31x9.5	56×12	0.8×0.55	Amber, yellow-green, no	FSTN Positive, STN Positive	No	5	0…50	-10…60
	KB145VG4	61×16	77x38x13	62×19	0.92×0.72	Amber, yellow-green		No	5	0…50	-10…60
	K145VG10	64x64	40x56x8.5	32×39.5	0.42×0.52	Amber, yellow-green, blue and white		No	3,3; 5	-20…70	-30…80

Distinctive features of MELT graphic displays are:

modern technologies STN Positive/Negative, FSTN Positive/Negative (Figure 3);
wide choice of resolutions: 122×32, 128×64, 61×16, 64×64;
various backlight colors: amber, yellow-green, red, blue, white;
various supply voltages: 2.8/3.0/3.3/5 V;
various operating temperature ranges, including -30…70°C.



Rice. 3. Examples of graphic LCD indicators MELT 128 x 64

An important distinguishing feature of most MELT graphic displays is the use of domestic LCD controllers.

K145VG10 is an LCD controller manufactured by ANGSTREM OJSC, similar to KS0108 manufactured by Samsung.

In addition to the compatibility of controllers, it is worth noting the compatibility of MELT displays with competitors’ products.

A few words about effective import substitution

Most MELT LCD displays are compatible with analogues from other manufacturing companies. At the same time, as shown above, LCDs from MELT are superior to them in terms of characteristics. This applies to both character-synthesizing or symbolic and graphic LCDs (Tables 4, 5).

Table 4. Compatibility of character-synthesizing or symbolic LCDs from various manufacturers

Format	Visible area, mm	Manufacturer/Name				Manufacturer/name
Format	Visible area, mm	Winstar	Powertip	Tianma	Bolymin	Microtips	Empire	Sunlike	Data Vision	Wintek
8×2	35.0×15.24				TM82A	BC0802A	MTC-0802X	AC082A			WM-C0802M
10×1	56.0×12.0		–	–	–	–	–	–	–	–	–
10×2	60.5×18.5	–	–		–	–	–	–	–	–	–
12×2	46.7×17.5	–			TM122A	BC1202A	–	–	–	–	–
16×1	64.5×13.8	–			TM161A	BC1601A1	MTC-16100X	AC161A			WM-C1601M
	66.0×16.0	–			–	BC1601B	–	–		–	–
	63.5×15.8	–	–	–	TM161E	–	–	–	–	–	–
	99.0×13.0				TM161F	BC1601D1	MTC-16101X	AC161B			WM-C1601Q
	120.0×23.0	–	–	–	–	–	–	AC161J	–		–
16x2	99.0×24.0				TM162G	BC1602E	MTC-16201X	AC162E			WM-C1602Q
	36.0×10.0	–	–		TM162X	–	–	–	–	–	–
	50.0×12.0	–	–	–	TM162B	–	–	–		–	–
	62.5×16.1				TM162V	BC1602B1	MTC-16202X	AC162A
	62.2×17.9	–	–	–	–	–	MTC-16203X	–	–		–
	62.2×17.9				TM162J	BC1602D	–	–			–
	62.2×17.9				TM162D	BC1602H	MTC-16204X	–			WM-C1602K
	62.5×16.1	–			TM162A	BC1602A	MTC-16205B	–			WM-C1602M
	55.73×10.98	–			–	BC1602F	–	–			–
	80.0×20.4	–	–	–	–	–	–	–	–		–
	80.0×20.4	–	–	–	–	–	–	–	–		–
16×4	61.4×25.0				TM164A	BC1604A1	MTC-16400X	AC164A			WM-C1604M
16×4	60.0×32.6	–		–	–	–	–	–	–	–	–
20×1	154×16.5	–	–	–	TM201A	–	–	–	–		–
20×1	149.0×23.0		–		–	–	–	–	–	–	–
20×2	83.0×18.8				TM202J	BC2002A	MTC-20200X	AC202A			WM-C2002M
	83.0×18.6	–	–	–	TM202A	–	–	–	–	–	–
	123.0×23.0	–			–	–	–	–	–	–	–
	149.0×23.0				TM202M	BC2002B	MTC-20201X	AC202B			WM-C2002P
	147.0×35.2	–	–	–	–	–	–	AC202D	–		–
	83.0×18.8	–	–	–	–	–	–	–	–		–
	76.0×25.2	–	–	–	–	–	–	–	–		–
20×4	76.0×25.2				TM204A	BC2004A	MTC-20400X	AC204A			WM-C2004P
	60.0×22.0	–	–		–	–	–	–	–	–	–
	77.0×26.3	–	–		–	–	–	–		–	–
	76.0×25.2	–	–		–	–	–	–		–	–
	123.0×42.5				TM204K	BC2004B	MTC-20401X	AC204B	–		WM-C2004R
24×1	178.0×23.0		–	–	TM241A	–	–	–	–	–	–
24×2	94.5×18.0				TM242A	BC2402A	MTC-24200X	AC242A			WM-C2402P
24×2	178.0×23.0		–		–	–	–	–	–	–	–
40×1	246.0×20.0	–	–		–	–	–	–	–	–	–
40×2	154.0×16.5	–			TM402A	BC4002A	MTC-40200X	AC402A			WM-C4002P
	153.5×16.5	–	–	–	TM402C	–	–	–	–	–	–
	246.0×38.0	–	–		–	–	–	–	–	–	–
40×4	147.0×29.5	–			TM404A	BC4004A	MTC-40400X	AC404A			WM-C4004M
	140.0×29.0	–	–		–	–	–	–		–	–
	244.0×68.0	–	–		–	–	–	–	–	–	–

Table 5. Compatibility of graphic LCDs from various manufacturers

Permission	Visible area, mm	Manufacturer/Name				Manufacturer/Name
Permission	Visible area, mm	Winstar	Powertip	Tianma	Bolymin	Microtips	Empire	Sunlike	Data Vision	Wintek
61×16	56.0×12.0		–	–	–	–	–	–	–	–	–
61×16	62.0×19.0		–	–	–	–	–	–	–	–	–
64x64	32.0×39.5		–	–	–	–	–	–	–	–	–
122×32	62.0×19.0				TM12232A		MTG-12232A	AG12232A			WM-G1203Q
	62.0×19.0		–	–	–	–	–	–	–	–	–
	85.0×26.0		–	–	–	–	–	–	–	–	–
128x64	71.7×38.5	Thus, the use of MELT products is exactly the case when import substitution turns out to be effective and profitable. Programming MELT LCD indicators In order to work with any LCD module, you need to implement basic software functions: reset and initialization, transmitting data and commands to the display, reading data from the display. The documentation for MELT LCD modules contains all the information necessary for this: the sequence and duration of signals during a hardware reset, a list of commands used, a description of the address space, a sequence of commands during a software reset and initialization, a detailed description of the data exchange interface. Of course, you can write software drivers yourself, that is, from scratch. However, in the vast majority of cases, a more correct and faster way would be to use the library of examples available for free download on the company’s website. In fact, this library contains templates for creating drivers in the C language. This means that the examples are not tied to specific controllers, and, accordingly, some of the functions, such as delay functions, I/O port settings, must be implemented independently. Thus, these programs will not compile, but can be the basis for creating drivers. Currently the library contains the following sample programs: AllText4.c – example for alphanumeric LCD indicators with 4-bit switching mode; AllText8.c – example for alphanumeric LCD indicators with 8-bit switching mode; MT-6116.c – example for the graphic LCD indicator MT-6116 with any letter index; MT-12232B.c – example for the graphic LCD indicator MT-12232B; MT-12232A,C,D.с – example for graphic LCD indicators MT-12232A, MT-12232C, MT-12232D; MT-12864.c – example for the MT-12864 graphic LCD indicator with any letter index; MT-6464B.c – example for the MT-6464B graphic indicator; MT-10T7,8,9.c – example for segment indicators MT-10T7, MT-10T8, MT-10T9; MT-10T11,12.c – example for segment indicators MT-10T11, MT-10T12. All examples contain basic functions: initialization, writing/reading a byte via a parallel interface, writing a command. For example, AllText8.c is a universal template for displays MT10S1, MT16S1, MT20S1, MT24S1, MT16S2, MT20S2, MT24S2, MT20S4, and contains four C functions: void LCDinit(void); void WriteCmd(byte b); void WriteData(byte b), void WriteByte(byte b, bit cd). Let's take a closer look at the void LCDinit(void) initialization function as an example of the implementation of the initialization function for alphanumeric LCD indicators with an 8-bit enable mode: void LCDinit(void) { LCD.E=0; Delay(>20ms); //if necessary, configure the data bus for output LCD.RW=0; LCD.A0=0; LCD.D=0x30; //set the interface type (8 bits) Delay(>40ns); //this is the address preset time (tAS) LCD.E=1; Delay(>230ns); //data preset time got here (tDSW) LCD.E=0; Delay(> LCD.E=1; Delay(>230ns); //minimum permissible signal duration E=1 LCD.E=0; Delay(>40us); //pause between commands LCD.E=1; Delay(>230ns); LCD.E=0; Delay(>270ns); //minimum permissible interval between signals E=1 //here the indicator enters the operating mode with the interface type set and commands can be issued as usual WriteCmd(0x3A); //setting the correct LCD mode WriteCmd(0x0C); //turn on the indicator, cursor is off WriteCmd(0x01); //clear the indicator WriteCmd(0x06); //setting the data input mode: move the cursor to the right } The analysis allows us to make several observations. Firstly, the function already contains the required signal sequence for hardware display configuration (LCD.E, LCD.RW, LCD.A0, LCD.D). Secondly, LCDinit uses the necessary time intervals and delays (Delay function). Third, LCDinit also contains a sequence of software initialization commands (the WriteCmd function). Thus, the user does not have to scrupulously read the documentation for the LCD module in search of all the necessary information. However, it is worth noting that the AllText8.c file does not contain an implementation of the delay function and the functions of initialization and work with I/O ports. The user must create them himself for the specific microcontroller used. All conclusions obtained remain valid for other functions from AllText8.c. Other examples from the MELT library are built on the same principle: all basic functions are implemented, the user only has to “bind” them to his controller. Application areas of MELT LCD indicators A wide range of models allows the designer to select the optimal LCD display based on the unique characteristics of a particular application. In fact, the MELT model range covers almost the entire range of possible areas of electronics from industrial equipment to portable devices and household appliances. However, there are a number of applications where MELT LCD displays are clearly superior to the competition. Automotive electronics. Experience in creating special-purpose automotive electronics shows that the choice of LCD display turns out to be one of the most critical design points. As an example, we can consider the control panel of the harvesting vehicle units (Figure 4). For ease of use, the remote control is installed on the dashboard. This means that in summer, in sunny weather, it experiences significant heating from the sun's rays, and in winter it must work at low temperatures, especially if the cleaning machine is parked outside (which is the norm for Russian realities). Thus, in accordance with GOST 15150-69, the remote control can be classified as product category 3 (or 3.1). This means that even for a climate version for a temperate climate, the maximum operating range, at best, will be -40...45°C. Nowadays it is not difficult to find microcircuits and electronic components that meet such requirements, which cannot be said about the LCD display. As a result, it is precisely because of this that it is necessary to urgently set a narrower range of operating temperatures in the technical specifications. This is easy to verify if you look at the characteristics of such products. For the vast majority of them, the operating range coincides with the storage range and is only -20...60°C. The use of MELT LCD displays immediately expands the operating range to -40...70°C, and the storage temperature - to -45...80°C. Industrial electronics. CNC operator consoles and control consoles, despite the proliferation of TFT and other display types, still often use standard LCD displays. In industrial production conditions, negative factors are increased dust levels and poor lighting quality. To achieve maximum operator comfort, it is necessary to provide high image contrast at large viewing angles. These are the qualities that distinguish MELT indicators. The support of the Russian character generator will also play an important role. Oil and gas industry. Geographically, the oil and gas industry in our country is located in the eastern and northeastern regions. They are characterized by a pronounced continental climate with low winter temperatures. At the same time, deposit development is very often carried out in hard-to-reach areas. For this reason, replacement of equipment in some cases may be physically unavailable if a breakdown occurs, for example, in a snow-covered camp. As a result, the electronics must provide the most reliable operation in harsh conditions. In such cases, is it worth saving and using LCDs produced by small companies from Southeast Asia? The answer is obvious. In this case, the highest reliability of MELT LCD displays makes them an ideal choice. Another important advantage of MELT displays is their cost. In this parameter, LCDs produced by MELT are not inferior to their Asian counterparts. For example, the wholesale cost of MT-08S2A is about 170 rubles. At the current dollar exchange rate, MELT products are cheaper than Asian analogues purchased at the production site. Custom LCD indicators and LCD panels The MELT company offers cooperation in the creation of custom LCD displays. At the same time, MELT takes care of all issues from development to production of these special indicators. The company’s wide production capabilities have already been described above. The options for custom LCD panels are extremely diverse. The company offers LCD panels using: various crystal technologies: TN, HTN, STN, FSTN; positive or negative display mode; various backlight colors: yellow-green, red, amber, blue, white, RGB; various operating temperature ranges, down to -40...70°C; manufacturing panels with rigid metal leads with a pitch of 0.8...4.0 mm; additional design requirements: a flexible printed circuit board with installation of the controller on glass (COG - chip on glass), contacts for electrically conductive rubber, and so on. The customer only requires technical specifications for the LCD panel or LCD indicator. You can learn more about the technical capabilities of producing and ordering LCD panels on the manufacturer’s official website: www.melt.com.ru. Conclusion MELT is one of the few Russian electronics manufacturers that produce high-quality products that are not inferior to foreign analogues, and in a number of parameters are superior to them. Thanks to an experienced development team and its own full production cycle, the company was able to bring to market more than six hundred LCD displays with various characteristics, such as: made using modern technologies: STN Positive/Negative, FSTN Positive/Negative; character-generating with various character and string formats: 08x2, 10x1, 16x1, 16x2, 16x4, 20x1, 20x2, 20x4, 24x1, 24x2; graphic with resolutions: 122×32, 128×64, 61×16, 64×64; with different backlight colors: amber, yellow-green, red, blue, white; with different supply voltages: 2.8/3.0/3.3/5 V; with different operating temperature ranges, including -30…70°C; with serial and parallel communication interface. A rich range of models, low cost, wide temperature range, support for Russian/English/Belarusian/Ukrainian/Kazakh character generators, high reliability - all this makes MELT displays an ideal choice for almost all areas of electronics. MELT company can develop and produce custom LCD indicators and panels. Literature http://www.melt.com.ru/.

Describing the differences between IPS and TN matrices as part of advice when buying a monitor or laptop. It's time to talk about all the modern display production technologies that we may encounter and have an idea about types of matrices in devices of our generation. Do not confuse with LED, EDGE LED, Direct LED - these are types of screen backlighting and display technologies are indirectly related.

Probably everyone can remember the monitor with a cathode ray tube that they used before. True, there are still users and fans of CRT technology. Currently, screens have increased in diagonal size, display manufacturing technologies have changed, and there are more and more varieties in the characteristics of matrices, denoted by the abbreviations TN, TN-Film, IPS, Amoled, etc.

The information in this article will help you choose a monitor, smartphone, tablet and other various types of equipment. In addition, it will highlight the technologies for creating displays, as well as the types and features of their matrices.

A few words about liquid crystal displays

LCD (Liquid Crystal Display) is a display made from liquid crystals that change their location when voltage is applied to them. If you come close to such a display and look closely at it, you will notice that it consists of small dots - pixels (liquid crystals). In turn, each pixel consists of red, blue and green subpixels. When voltage is applied, the subpixels are arranged in a certain order and transmit light through them, thus forming a pixel of a certain color. Many such pixels form an image on the screen of a monitor or other device.

The first mass-produced monitors were equipped matrices TN- having the simplest design, but which cannot be called the highest quality type of matrix. Although among this type of matrices there are very high-quality specimens. This technology is based on the fact that in the absence of voltage, subpixels transmit light through themselves, forming a white dot on the screen. When voltage is applied to the subpixels, they are arranged in a certain order, forming a pixel of a given color.

Disadvantages of TN matrix

Due to the fact that the standard pixel color, in the absence of voltage, is white, this type of matrix does not have the best color rendering. Colors appear duller and faded, and blacks appear more of a dark gray.
Another main disadvantage of a TN matrix is small viewing angles. Partially they tried to cope with this problem by improving TN technology to TN+Film, using an additional layer applied to the screen. Viewing angles became larger, but still remained far from ideal.

At the moment, TN+Film matrices have completely replaced TN.

Advantages of TN matrix

fast response time
relatively inexpensive cost.

Drawing conclusions, we can say that if you need an inexpensive monitor for office work or surfing the Internet, monitors with TN+Film matrices are best suited.

The main difference between IPS matrix technology and TN— perpendicular arrangement of subpixels in the absence of voltage, which form a black point. That is, in a state of calm the screen remains black.

Advantages of IPS matrices

better color reproduction compared to screens with TN matrices: you have bright and rich colors on the screen, and black remains truly black. Accordingly, when voltage is applied, the pixels change color. Considering this feature, owners of smartphones and tablets with IPS screens can be advised to use dark color schemes and wallpapers on the desktop, then the smartphone’s battery life will last a little longer.
large viewing angles. On most screens they are 178°. For monitors, and especially for mobile devices (smartphones and tablets), this feature is important when the user chooses a gadget.

Disadvantages of IPS matrices

long screen response time. This affects the display in dynamic pictures such as games and movies. In modern IPS panels, things are better with response time.
higher cost compared to TN.

To summarize, it is better to choose phones and tablets with IPS matrices, and then the user will receive great aesthetic pleasure from using the device. The matrix for a monitor is not so critical, modern ones.

AMOLED screens

The latest smartphone models are equipped with AMOLED displays. This technology for creating matrices is based on active LEDs, which begin to glow and display color when voltage is applied to them.

Let's take a look features of Amoled matrices:

Color rendition. The saturation and contrast of such screens are higher than required. The colors are displayed so brightly that some users may experience eye strain when using their smartphone for long periods of time. But the black color is displayed even blacker than even in IPS matrices.
Display power consumption. Just like IPS, displaying black requires less power than displaying a specific color, much less white. But the difference in power consumption between displaying black and white in AMOLED screens is much greater. Displaying white requires several times more energy than displaying black.
"Picture Memory". If a static image is displayed for a long time, marks may remain on the screen, and this in turn affects the quality of the information displayed.

Also, due to their rather high cost, AMOLED screens are currently only used in smartphones. Monitors built on this technology are unreasonably expensive.

VA (Vertical Alignment)- this technology, developed by Fujitsu, can be considered as a compromise between TN and IPS matrices. In VA matrices, the crystals in the off state are located perpendicular to the screen plane. Accordingly, the black color is ensured as pure and deep as possible, but when the matrix is rotated relative to the direction of view, the crystals will not be visible equally. To solve the problem, a multi-domain structure is used. Technology Multi-Domain Vertical Alignment (MVA) provides protrusions on the plates that determine the direction of rotation of the crystals. If two subdomains rotate in opposite directions, then when viewed from the side, one of them will be darker and the other lighter, so for the human eye the deviations cancel out. There are no protrusions in PVA dies developed by Samsung, and the crystals are strictly vertical when turned off. In order for the crystals of neighboring subdomains to rotate in opposite directions, the lower electrodes are shifted relative to the upper ones.

To reduce response time, Premium MVA and S-PVA matrices use a dynamic voltage increase system for individual sections of the matrix, which is usually called Overdrive. Color rendition of PMVA and SPVA matrices is almost as good as that of IPS, response time is slightly inferior to TN, viewing angles are as wide as possible, black color is the best, brightness and contrast are the highest possible among all existing technologies. However, even with a slight deviation of the viewing direction from the perpendicular, even by 5–10 degrees, distortions in halftones can be noticed. This will go unnoticed by most, but professional photographers continue to dislike VA technology for this.

MVA and PVA matrices have excellent contrast and viewing angles, but the situation with response time is worse - it grows as the difference between the final and initial states of the pixel decreases. Early models of such monitors were almost unsuitable for dynamic games, but now they show results close to TN matrices. Color rendering *VA matrices, of course, is inferior to IPS matrices, but remains at a high level. However, due to their high contrast, these monitors are an excellent choice for working with text and photography, with drawing graphics, and also as home monitors.

In conclusion, I can say that the choice is always yours...

Transparent, flexible and made from organic materials, the displays of the future will adapt to our needs. Some devices with new screens are available on the market today. Flexible displays from Plastic Logic are extremely thin and can be rolled up like a newspaper. Finally, they have appeared - ultra-thin TVs with OLED displays, which have been presented to the public more than once in the form of concepts or prototypes at specialized exhibitions. Most likely, they will soon become available in our stores. What is first striking is not so much the thickness of these devices - from 4 to 8 mm - but their high cost: the first models will cost owners approximately 350,000 rubles. At the same time, in terms of the image quality that the LED display itself demonstrates, it can be argued that it has made a giant leap forward. And once mass production is established, OLED-based displays will become significantly cheaper. Mobile devices today use new generation screens with HD resolution; in the future, these gadgets will become even thinner thanks to the use of modern technologies. E-readers with E-Ink color displays are already being sold in some Asian countries today. It will only take some time before they appear all over the world.

Solutions for the future today

Samsung and LG are presenting huge OLED TVs, while Sony is relying on color LEDs. Transparent OLED displays are also coming soon.

TVs made using Edge-LED (edge-illuminated LED) technology tend to have low contrast. The problem is solved by Direct-LED technology, used in premium devices. A panel of white LEDs located behind the LCD matrix illuminates it evenly across the entire width of the screen. Due to the fact that this technology allows individual groups of LEDs to be turned off, higher contrast is achieved compared to Edge-LED backlighting. However, in this direction, Sony was ahead of its competitors by recently introducing a 55-inch TV with a display made of Crystal-LED technology. An image point on the screen of this TV is formed by three pixels, each of which consists of three subpixels - red, green and blue. At Full HD resolution, the quantity is 6,220,800 pieces. According to the company, in comparison with classic LCD TVs, this provides the following advantages: image contrast increases by 3.5 times, color gamut increases by 1.4 times, and in addition, large viewing angles and instant response time are provided.

TVs with OLED displays that use organic light-emitting diodes promise higher energy efficiency and contrast: they do not require backlighting, since they themselves are the light source. Samsung and LG have already presented the first 55-inch prototypes. Korean engineers claim to have overcome the inherent problems of OLED technology, which include color distortion and short service life.

Classic LCD matrix with Direct-Led photo backlight	OLED from LG: a luminous “sandwich” and a layer of color filters

Transparent displays

Among all manufacturers, so far only Samsung has launched the production of a TV that is as transparent as glass when turned off. The transparency of the display is achieved through the use of a traditional LCD matrix and TOLED technology (transparent organic light-emitting diodes). The device allows you to display videos, applications and widgets on the screen. The resolution of the 46-inch display is 1680x1050 pixels, the contrast, according to engineers, is 500:1. The TV has a touch control unit, thanks to which you can interact with applications by touching your fingers. The light source is the surrounding space; if necessary, the side LEDs are turned on. It’s also great that you can dim your TV using a special app. If you pull the virtual cord, the virtual blinds will close and the transparency will disappear.

The company "GT Light" entered the market of LED products in 2002. The main activity of the enterprise is the production of LED screens. Currently, the company has large-scale production facilities in China, as well as in Russia, in Novokuznetsk.

The extensive experience gained over many years makes the company's work impeccable: the production and installation of LED products is always carried out flawlessly and to the highest standards.

Production of LED screens, photo 8

Making LED Screens: Production Step by Step

GT Light LLC has automated production in China.

Production of LED screens, photo 7

The production of LED screens occurs in the course of a streamlined, failure-free technological process, which has the following production stages:

Design: the module circuit and printed circuit board are being developed. The necessary parts are purchased from trusted manufacturers.
Production: all required elements are manufactured according to our own drawings.
Assembly: all components are soldered onto a printed circuit board produced according to our drawings, and a protective coating of the required level is applied on top of the board.
Inspection: Comprehensive quality control takes place, during which any defects are identified and eliminated.
The production of other products manufactured at the plant operates on the same principle, including: tickers, video screens for the street, media facades.

As a Russian manufacturer of LED displays, we also have our own large production workshop in Russia, which allows us to produce the most complex products in compliance with all requirements.

Manufacturers of LED screens are a priority

Currently, the production of LED screens in Russia is considered a profitable business, since LED displays are widely used in everyday life. But not every company is a manufacturer. Often a supplier masquerades as one and does not guarantee either the reliability of the product or proper service.

The manufacturing company "GT Light" has serious advantages over intermediaries:

We guarantee the quality of our products;
We provide warranty service;
We provide 24/7 technical support.

Prices for various types of LED screens can be found in the relevant sections of the website. Our company’s specialists can advise you on product selection by calling 8-800-555-05-07. They will always be happy to help you.