SJ 20639-1997 Specification for black guest-host liquid crystal materials
Some standard content:
Military Standard for Electronic Industry of the People's Republic of China FL5971
SJ20639-97
Specification for black guest-host liquid crystal1997-06-17 Issued
1997-10-01 Implementation
Approved by the Ministry of Electronics Industry of the People's Republic of China Military Standard for Electronic Industry of the People's Republic of China Specification for black guest-host liquid crystal material
Specification for black guest-host liquid crystal1 Scope
1.1 Subject Content
SJ 20639-97
This specification specifies the requirements, quality assurance provisions, delivery preparation and related provisions for black guest-host (GH type) liquid crystal materials.
1.2 Scope of Application
This specification applies to black guest-host liquid crystal materials (hereinafter referred to as liquid crystal materials) used in liquid crystal display devices. 2 Referenced Documents
No provisions in this chapter.
3 Requirements
3.1 Qualification
Products submitted in accordance with this specification shall be qualified products or approved products. 3.2 Trial samples
When specified in the contract, the contractor shall provide trial samples. Unless otherwise specified, the trial samples shall meet all the requirements of this specification.
3.3 State
At room temperature, the liquid crystal material is liquid.
3.4 Colorwww.bzxz.net
The liquid crystal material is black.
3.5 Melting point
The melting point of the liquid crystal material shall be lower than -40℃.
3.6 Clearing point
The bright spot of the liquid crystal material shall not be lower than 85℃.
3.7 Viscosity
The viscosity of the liquid crystal material shall be less than 30mm/s (20℃). 3.8 Resistivity (g)
The resistivity of the wave crystal material shall be greater than 1×10\·cm. 3.9 Optical anisotropy (An)
Promulgated by the Ministry of Electronics Industry of the People's Republic of China on June 17, 1997 and implemented on October 1, 1997
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SJ 20639--97
The optical anisotropy of liquid crystal materials is 0.08~0.15. 3.10 Extraordinary refractive index (n)
The extraordinary refractive index of liquid crystal materials is 1.5~1.7. 3.11 Dielectric anisotropy (4)
The dielectric anisotropy of liquid crystal materials is -5~25. 3.12 Dielectric constant (e)
The dielectric constant of liquid crystal materials is 230 when the liquid crystal director is parallel to the electric field. 3.13 Reading voltage (V10,0.20)
The reading voltage of liquid crystal materials is 1.0~3.0V. 3.14 Saturation voltage (Vo, 0.20)
The saturation voltage of the liquid crystal material is 2.0~4.5V. 3.15 Total dye concentration
The total dye concentration of the liquid crystal material is 2.0~4.0%. 4 Quality Assurance Provisions
4.1 Inspection Responsibility
Unless otherwise specified in the contract or order, the contractor shall be responsible for completing all inspections specified in this specification. If necessary, the ordering party or the superior appraisal agency has the right to inspect any inspection item described in this specification. 4.1.1 Qualification Responsibility
All products must meet all requirements of Chapter 3 and Chapter 5 of this specification. The inspections specified in this specification shall become an integral part of the contractor's entire inspection system or quality program. If the contract includes inspection requirements not specified in this specification, the contractor shall also ensure that the products submitted for acceptance meet the requirements. Quality consistency sampling does not allow the submission of products that are known to be defective, nor can it require the ordering party to accept defective products. 4.2 Inspection classification
The inspections specified in this specification are divided into:
a, identification inspection;
b, quality consistency inspection.
4.3 Environmental requirements
Unless otherwise specified, various inspections shall be carried out according to the following environmental conditions: Ambient temperature: 15~35℃;
Relative coagulation: 45%~75%;
Atmospheric pressure: 86~106kPao
4.4 Identification inspection
Identification inspection is carried out before the product is submitted. When there are major changes in raw materials or manufacturing processes that may affect the identification results, identification inspection shall also be carried out.
4.4.1 Inspection location
Unless otherwise specified, the location of trial production inspection is a laboratory or testing center approved by the relevant competent authorities. 4.4.2 Inspection items
Randomly select 10g samples from the same batch of products and inspect them according to Table 1. 2
Mischarged point
Resistivity (p)
Optical anisotropy (An)
Anisotropic refractive index (ne)
Dielectric anisotropy (4e)
Dielectric band number (en)
Value voltage (V10.0,20)
Galvanic conductivity (Vgm.0.20)
Total dye concentration
4.4.3 Determination of failure
SJ 20639-97
Table 1 Identification and inspection
Required chapter number
Inspection method chapter number
If the test sample passes all the inspections or tests listed in Table 1, the identification and inspection is qualified: if one item is unqualified, the qualification will not be granted.
4.5 Quality consistency inspection
4.5.1 Composition of inspection batch
An inspection batch shall consist of all products with the same liquid crystal monomer, the same formula, produced under basically the same conditions and submitted for inspection at the same time.
4.5.2 Quality consistency inspection form
Quality consistency inspection Randomly select 10g samples from the same batch of products and inspect them according to Table 1. They shall all meet the requirements of this specification.
4.5.3 Unqualified
If one or more of the inspections specified in Table 1 fail, the batch shall be judged as unqualified, and the acceptance and delivery of the products shall be stopped. The contractor may take corrective measures, correct the defects, and resubmit for inspection. The resubmitted inspection batch shall be separated from the normal batch and clearly marked as the re-inspected batch. If the re-inspected batch still fails, the batch shall be judged as unqualified. 4.6 Packaging inspection
The packaging and marking requirements specified in Chapter 5 of this specification shall be inspected by visual method. 4.7 Inspection method
4.7.1 Inspection of state
Inspect by self-viewing method, and shall meet the requirements of Article 3.3. 4.7.2 Inspection of color
Inspect by moon-viewing method, and shall meet the requirements of Article 3.4. 4.7.3 Measurement of melting point
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4.7.3.1 Principle overview
SJ 20639-97
The measurement of melting point and clearing point of the crystal adopts differential thermal analysis method. The sample and the reference substance are heated or cooled under the same conditions. The differential thermal band between the sample and the reference substance is measured by two relatively connected thermocouples. The two junctions of the thermocouple are in contact with the sample and the reference substance respectively. The electromotive force of the thermocouple is proportional to its temperature difference. The temperature difference electromotive force is amplified and recorded by the detection instrument (such as XY recorder), and the differential thermal analysis curve, i.e., △T～T(t) graph, can be obtained. The sample and the reference are heated or cooled under the same conditions. If the sample does not produce any thermal effect, that is, the sample temperature T is equal to the reference temperature T, then 4T=Ts-T,=0, and the XY recorder does not indicate any thermoelectric potential. If the sample absorbs heat or releases heat, then AT=T-T, and the thermoelectric potential is less than zero or greater than zero. The differential thermal analysis curve of AT=f(T) can be obtained on the XY recorder. Since the liquid crystal absorbs heat during the phase change (heating process), more than two absorption peaks will appear on the differential thermal analysis curve. According to the position of these absorption peaks, the phase change temperature of the liquid crystal can be accurately determined, thereby obtaining the dark point and the pooling point, etc.
4.7.3.2 Measuring equipment
Differential thermal analyzer (DSC)
4.7.4 Measurement of melting point and clearing point
Measure the melting point and clearing point according to the measurement method in 4.7.3. 4.7.5 Measurement of viscosity
4.7.5.1 Measuring equipment
, constant temperature (accuracy ±1°C);
b, semi-micro capillary viscometer (container volume 8mL, accuracy ±1mm2/s); c. stopwatch.
4.7.5.2 Measurement steps
Put the capillary viscometer with the liquid to be tested in a constant temperature bath for half an hour, use an air pump to suck the liquid crystal to the scale, remove the air pump to allow the liquid crystal to flow freely through the capillary tube, and time it at the same time, record the time t for the entire flow to be completed (should be between 100 and 200 seconds), and calculate the viscosity according to formula (1).
Where: kinematic viscosity of the liquid, mm/s;
c——viscometer constant, mm\/s:
t——time for liquid to flow out, Sc
4.7.6 Measurement of resistivity
4.7.6.1 Measurement method
Insert the conductivity electrode into the liquid crystal to be tested, and use the ultra-high resistance tester to measure its resistance R. The area of the platinum sheet of the conductivity electrode and the distance between the two platinum sheets are known. According to formula (2), the resistivity of the liquid crystal to be tested can be calculated. O=R·S/1...
Where: p——resistivity, ncm;
R——resistance,;
S——area of the platinum sheet of the conductivity electrode, cm2: [—height between the two platinum sheets of the conductivity electrode, cm. 4.7.6.2 Measurement equipment
B. Ultra-high resistance tester (capable of measuring resistance greater than 1017Q); 6 conductivity electrodes.
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4.7.6.3 Measurement steps
SI20639-97
Use a clean and dry 100mL small beaker to take 30mL of the newly mixed special test liquid crystal sample, keep the temperature at 20±2°C, measure the resistance with a conductivity electrode, record its resistance value R, and calculate the resistivity (Q·cm) according to formula (2). 4.7.6.4 Error
The accuracy of measurement using this method mainly depends on the accuracy of the ultra-high resistance tester. When the resistivity is between 1×1010 and 2×10110cm, the error generally does not exceed ±10%. When the resistivity is between 1×1011 and 2×1012n·cm, the error does not exceed ±20%.
4.7.7 Measurement of optical anisotropy (An)
4.7.7.1 Measurement method
In the liquid crystal medium, the linear polarized light whose light vector vibration direction is perpendicular to the long axis of the liquid crystal molecule is called ordinary light (. light). The ratio of the speed of light in vacuum to the speed of ordinary light in the liquid crystal medium is called the ordinary light refractive index (n.). The linear polarized light whose light vector vibration direction is parallel to the long axis of the liquid crystal medium molecule is called extraordinary light (e light). The ratio of the speed of light in vacuum to the speed of extraordinary light in the liquid crystal medium is called the extraordinary light refractive index (n.). The optical anisotropy (△n) is the difference between the extraordinary light refractive index (n) and the ordinary light refractive index (n.), that is: An=n,-
A layer of vertical alignment agent is evenly coated on the optical glass surface and the frosted glass surface of the Abbe refractometer, so that the liquid crystal molecules to be measured are vertically aligned in a certain direction, and a polarizer is attached to the eyepiece of the Abbe refractometer. When the incident direction of the light, the arrangement direction of the liquid crystal molecules and the polarization direction of the polarizer are as shown in Table 2, n. and n. are measured respectively, and 4n is calculated according to formula (3). Table 2ne,. Relationship between incident light direction, arrangement direction of liquid crystal molecules and polarization direction of polarizer p(n.)
Incident light direction
Orientation direction of liquid crystal molecules→
Polarization direction of polarizer
4.7.7.2 Measuring equipment
a. Abbe refractometer;
b. Low temperature constant temperature bath.
4.7.7.3 Measuring steps
Evenly apply a layer of vertical alignment agent on the optical glass and frosted glass surface of the Abbe refractometer and let it air dry naturally. Adjust the polarization direction of the polarizer on the eyepiece to the direction of the measurement as shown in Table 2. Drop the liquid crystal to be tested on the treated glass surface, start the low temperature constant temperature bath, and when the temperature is constant at 20, adjust the field of view of the solar mirror to make the crosshairs image clear, and rotate the adjustment knob to the position of the light and dark dividing line in the field of view of the eyepiece so that the dividing line is located at the center of the crosshairs. It can be read on the scale below the eyepiece field of view. Rotate the polarization direction of the polarizer on the eyepiece by 90 degrees, rotate the adjustment knob to find another light-dark dividing line in the eyepiece field of view, and make the dividing line at the center of the crosshairs. At this time, the value shown on the scale below the eyepiece field of view is the value of the liquid crystal to be measured. Then, △n is obtained by formula (3). The measurement accuracy of this method is ±0.005. 4.7.8 Measurement of extraordinary light refractive index (n.) Measure n according to the measurement method in 4.7.7. c4.7.9 Measurement of dielectric anisotropy (4e)
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4.7.9.1 Measurement method
Under the action of electric field, liquid crystal molecules follow the orientation of the electric field, and the long axis of the molecules is consistent with the direction of the electric field (liquid crystal with 4e>0). At this time, the direction of the liquid crystal is parallel to the electric field, and the measured dielectric constant is called, on the contrary, when the liquid crystal director is perpendicular to the electric field, the measured dielectric constant is called ε. Figure 1 is a schematic diagram of the liquid crystal dielectric anisotropy measurement device. Precision LCR meter
Computer
Figure 1 Liquid crystal dielectric anisotropy measurement device diagram The liquid crystal box used for measurement is a parallel box, and the empty box capacitance is C. 。 The liquid crystal to be tested is injected into the liquid crystal box. When the liquid crystal director is perpendicular to the electric field, C+ is measured. When the liquid crystal director is parallel to the electric field, C is measured. By using formulas (4), (5), and (6), e#, E1, and Az=ci/c
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, the liquid crystal molecules near the two inner surfaces of the liquid crystal box are affected by the boundary conditions. Under the action of the electric field, their molecular long axis (liquid crystal with e>0) may not be completely consistent with the direction of the electric field. In order to keep the long axis of the liquid crystal molecules completely consistent with the direction of the electric field, a very high voltage must be applied, which is difficult to measure. Therefore, the extrapolation method shown in Figure 2 is used to deduce the capacitance C when the voltage is infinite, thereby ensuring the accuracy of C measurement. In Figure 2, the ordinate is capacitance (C), and the abscissa is 1/V. The capacitance C is linearly related to 1/V. The intersection of the extended oblique line and the ordinate is the calculated capacitance Cu when the voltage is infinite. c
Figure 2 Schematic diagram of extrapolation method to calculate capacitance C when voltage is infinite 4.7.9.2 Measuring equipment
, a precision LCR meter;
b. a computer.
4.7.9.3 Preparation of test box
SJ 2063997
Photolithography of 1cm2 circular electrode pattern on conductive glass (LITO glass) to make a parallel test box as shown in Figure 1, with a plate thickness of 7μm.
4.7.9.4 Measurement steps
, measure the empty box capacitance C of the test box.
b. Inject the liquid crystal to be tested into the test box, apply a voltage of 100mV (square wave, 1.6kHz) to the liquid crystal box, and measure C1. Apply the measurement voltage to the liquid crystal box, draw a C1/V graph, and the extrapolation oblique line intersects with the vertical axis to obtain the capacitance Cu when voltage is infinite.
Substitute the unique C., C and extrapolated C into formula (4) to calculate l, e and Ze. The accuracy of measuring 4e by this method is:
4e>10 Error ±0.5;
<10 Error ±0.3a
4.7.10 Measurement of dielectric constant (e)
Measure according to the measurement method in 4.7.9*. 4.7.11 Measurement of threshold voltage (V10, 0.20) 4.7.11.1 Measurement method
In a guest-host liquid crystal display device, the effective value of the applied voltage when the change of the light transmittance or absorption rate of the display part reaches 10% of its maximum is called the threshold voltage (V10), and the effective value of the applied voltage when the change of the light transmittance or absorption rate of the display part reaches 90% of its maximum is called the saturation voltage (V). When the driving voltage of the liquid crystal display device gradually increases, its transmittance gradually changes, and the electro-optical response curve is shown in Figure 3. 0
Figure 3 Electro-optical response curve of liquid crystal display device 4.7.11.2 Measuring equipment
The measuring equipment is shown in Figure 4.
a: Incandescent lamp;
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b. Collimator:
c Polarizer;
d, Small angle light intensity meter;
e. Signal generator;
to. Computer.
Collimator
4.7. 11.3 Measurement steps
SJ20639-97
Signal generation number
Computer
Figure 4 Schematic diagram of the electro-optical response curve measurement device Small cannon light intensity
Measuring instrument
Inject the liquid crystal to be tested into the liquid crystal cell (TN cell, the cell thickness is 9μm),The direction of the polarizer P is consistent with the long axis direction of the liquid crystal molecules near the inner surface adjacent to the liquid crystal box. The light incident direction is perpendicular to the surface of the liquid crystal box. The driving voltage of the liquid crystal box is provided by a signal generator (square, 32Hz), and the voltage is increased by 1V per second. When the voltage gradually increases, the continuous change of the transmittance is measured. The light intensity passing through the liquid crystal box is measured by a small-angle light intensity measuring instrument and input into the computer. After processing, the electro-optical response curve of the liquid crystal box and the values of Vi and Vgo are obtained. The entire sputtering process is carried out at 20°C. The measurement error is ±0.05V. 4.7.12 Measurement of saturation voltage (Vg0.0.20) Measure Vg0.0,20a according to the measurement method in 4.7.11. 4.7. 13 Measurement of total dye concentration
4.7.13.1 Measuring equipment
Precision balance (sensitivity 0.0001g)
4.7.13.2 Measurement steps
Accurately weigh the liquid crystal XI (g), dye Xz (g), then the total dye concentration C is: C
×100%
Xi + X2
The total dye concentration is controlled by the contractor.
5 Delivery preparation
5.1 Packaging and packaging
Sealed packaging with borosilicate hard glass bottles.
5.2 Transportation and storage
SJ 2063997
It can be transported by any means and should be handled with care during loading and unloading. The product should be stored in a dry room without direct sunlight. Marking
The packaging container of the product should be labeled with the following information: a. Product brand;
b. Net weight;
c. Production date;
d. Production unit.
Notes
6.1 Intended use
The liquid crystal materials specified in this specification are intended to be used in liquid crystal display devices. 6.2 Contents of order documents
The following contents shall be stated in the contract or order form: a. Name and number of this specification;
b. Brand of material;
c. Weight of material;
d. Special packaging requirements;
e. Special marking requirements;
f. Others.
Additional remarks:
This specification is under the jurisdiction of China Electronics Standardization Institute. This specification was drafted by China Electronics Standardization Institute. The main drafters of this specification are: Xu Shouyi, Tang Hong, Yao Naiyan, Liu Yun. 9
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