Some standard content:
National Standard of the People's Republic of China
Test methods for fluorescent display tubes
Methods of measurement for
fluurescent display tubes
1 Subject content and scope of application
This standard specifies the test methods for the optoelectronic parameters of fluorescent display tubes. This standard applies to the test of optoelectronic parameters of fluorescent display tubes (hereinafter referred to as fluorescent tubes). 2 Reference standards
GB2421 General rules for basic environmental testing procedures for electrical and electronic products GB4597 Terminology of electron tubes
GB5998 Test methods for color picture tubes
GB9430 Test methods for brightness stability of fluorescent digital display tubes 3 General requirements
3.1 Test equipment
3.1.1 The test equipment shall comply with the requirements of the regulations, specifications and safety standards for electrical test equipment. GB/T 3790—1995
Replaces GB3790—83
3.1.2 The insulation resistance between the test tube socket jacks should be no less than 100Ma. 3.1.3 In order to protect the fluorescent tube and instrument under test and prevent sudden overload, it is allowed to take protective devices on the equipment, but it does not affect the test accuracy. 3.1.4 The test equipment should be calibrated regularly by the metering department. 3.1.5 The arrangement and fixed position of the instruments on the test equipment should facilitate the operator to read the readings correctly and minimize visual errors. 3.1.6 The structure of the test equipment should be considered for easy operation and maintenance. 3.2. Electrical instruments
3.2.1 The accuracy of the meter used to test the photoelectric parameters of the fluorescent tube should not be lower than Class 1.5. 3.2.2 The instrument range selected for the test equipment should ensure that the measured reading is greater than one-third of the full scale. 3.2.3 When measuring with a voltmeter, the voltage drop on the line between the voltmeter and the tube socket should not exceed 0.2% of the rated voltage, and the current passing through the voltmeter should not exceed 0.5% of the measured current, otherwise it should be corrected. 3.3 Power supply
3.3.1 The ripple coefficient of the DC power supply voltage of the test equipment should not be greater than 1%, and the stability should not be less than 1%. 3.3.2 The fluctuation of the filament voltage should not be greater than ±1%. 3.3.3 The pulse width and repetition frequency of the pulse power supply voltage are specified in the detailed specifications. Its internal resistance should meet the following requirements: when the load current of the fluorescent tube changes from zero to the maximum value, the change of the output voltage is not greater than %. If the requirements cannot be met, correction methods such as correction method or dummy load are allowed.
The pulse is shaped as shown in Figure 1.
The pulse rise time should not exceed 10% of the pulse duration; National Technical Supervision Bureau approved on July 24, 1995, implemented on April 1, 1996
GB/T 3790—1995
The pulse fall time should not exceed 20% of the pulse duration.
3.4 Test brightness device
Pulse opening time
Item Yu Jiangyou
Pre-hard mosquito
Pulse fall time
3.4. 1 The interior of the test brightness device should be painted black (the coating should not reflect light). 3.4.2 A light bar should be placed in the test brightness device, and the photoelectric element should not receive background light. %
Pulse amplitude
Forward shooting
Reverse shooting
3.4.3 The distance between the photoelectric element of the test brightness device and the light-emitting surface of the fluorescent tube should be more than 5 times the diameter of the light-emitting surface (or the diagonal length). 3.4.4 A color filter should be placed in the test brightness device, and the spectral characteristic curve of the combination of the visual color filter and the photoelectric element should be pre-calibrated to the spectral luminous efficiency of bright vision. The degree of consistency should comply with the provisions of Appendix A (Supplement). 3.5 Test environmental conditions
3.5.1 Unless otherwise specified, the test of the photoelectric parameters of the fluorescent tube should be carried out under the positive atmospheric conditions specified in GH2421 (ambient temperature is 15C35'C, relative humidity is 45%~～75%, and air pressure is 86~～106 kPa). 3.5.2 When testing the photoelectric parameters of the fluorescent tube, its visual background light should not exceed 501x, and the distance to the light-emitting surface is 40 times the height of the characters. 4 Photoelectric parameter test
cathode current
4.1 cathode current
4.1. 1 definition
The sum of the currents flowing through the grid and anode loops under specified working conditions. 4.1.2 cathode dc current4.1.2.1 The test circuit diagram is shown in Figure 2. GB/T 3790—1995
4. 1. 2. 2 Test procedure
According to the detailed specifications, apply voltage to each electrode of the fluorescent tube and read the cathode current from the grid and anode loop ammeter. 4.1.3 cathode pulse current.4.1.3.1 test circuit diagram
The voltage sampling method test circuit diagram is shown in Figure 3. Figure 3
R-dead inductive resistor, the voltage drop on the resistor should not be greater than one-half of the source voltage-P, P., P:-peak voltage meter or oscilloscope average component method test circuit diagram as shown in Figure 4, b.
4.1. 3.2 Test procedure
a, voltage sampling method
GB/T 3790-1995
PI, P.-peak voltage meter or oscilloscope
According to the detailed specifications, apply voltage to each pole of the fluorescent tube. Test the pulse voltage U at both ends of the non-inductive resistor of the anode loop. The cathode pulse current IkP is calculated as follows:
b, average component method
According to the detailed specifications, apply voltage to each pole of the fluorescent tube, and test the cathode pulse current average value Ikp on the DC ammeter of the anode loop. The cathode pulse current Ik is calculated as follows: Tke = IT
Where: T is the repetition period of the gate and anode pulse voltages·s: r is the width of the gate and anode pulse voltages. 4.2 Anode current anode current
4.2.1 DefinitionbZxz.net
The current flowing through the anode circuit under specified working conditions. 4.2.2 Anode DC current aoded.c.curren4.2.2.1 The test circuit diagram is shown in Figure 5. .(2)
GB/T 3790 1995
4.2.2.2 Test procedure
According to the detailed specifications, a voltage is applied to each electrode of the fluorescent tube, and the anode DC current is read from the anode circuit DC meter: 4.2.3 Anode pulse current anodc pulse current4.2.3.1 Test circuit diagram
The voltage joint sample method test circuit diagram is shown in Figure 6. 88
P., P: Peak voltage meter or oscilloscope
The average component method test circuit diagram is shown in Figure 7. Measuring range determiner
4.2.3.2 Test procedure
a. Voltage sampling method
GB/T 3790—1995
P:, P.-Peak voltage meter or oscilloscope
According to the detailed specifications, apply E voltage to each electrode of the fluorescent tube, and test the pulse voltage UP at both ends of the non-inductive resistor of the anode loop. The anode pulse current Ip is calculated as follows:
b. Average component method
According to the detailed specifications, apply voltage to each electrode of the fluorescent tube, and test the average value of the anode pulse current I on the DC ammeter of the anode loop. The anode pulse current Ir is calculated as follows:-
(4)
Where: T is the repetition period of the gate and anode pulse voltage, s; the width of the gate and anode pulse voltage, s. 4.3 Grid current grid current
4.3.1 Definition
The current flowing through the grid loop under specified working conditions. 4.3.2 Grid DC current grid dccurrent4.3.2.1 The test circuit diagram is shown in Figure 8. GB/T 3790—1995
4.3.2.2 Test procedure
According to the detailed specifications, apply voltage to each electrode of the fluorescent tube and read the grid DC current from the grid loop DC ammeter. 4.3.3 Grid pulse current grid pulsecrnt4.3.3.1 Test circuit diagram
The voltage sampling method test circuit diagram is shown in Figure 9. Continental frequency controller
P:, P.—Peak voltage meter or oscilloscope
b. The average component method test circuit diagram is shown in Figure 10. 4.3.3.2 Test procedure
a. Voltage test method
GB/T 3790 1995
P, P: Peak voltage meter or oscilloscope
According to the detailed specifications, apply voltage to each electrode of the fluorescent tube and test the pulse voltage U7R at both ends of the non-inductive resistor of the grid circuit: grid pulse current I,Calculate as follows:
b, Average component method
According to the detailed specifications, apply voltage to each electrode of the fluorescent tube, and test the average value of the gate pulse current on the gate loop ammeter7: The gate pulse current I is calculated as follows:
Where: T-repetition period of gate and anode pulse voltage·width of gate and anode pulse voltage, s. 4.4 Grid cut-off voltage grid cut-off voltage4. 4.1 Definition
Under the specified working conditions, visually observe the gate voltage when the light on the display surface just disappears. 4.4.2 The test circuit diagram is shown in Figure 11.
GB/T3790
Note: Taking the anode current voltage as an example,
4.4.3 Test procedure
According to the detailed specifications, add filament and anode voltage to the fluorescent tube, then adjust the grid voltage, make the fluorescent tube glow, and then gradually reduce the grid voltage until the fluorescent tube display surface just disappears or the brightness of the fluorescent tube display surface drops to 0.3ci/m, and read the grid cut-off voltage from the grid voltage meter.
4.5 Anode cut-off voltage4.5.1 Definition
Under the specified working conditions, the anode voltage when the display surface just disappears visually. 4.5.2 The test circuit diagram is shown in Figure 12.
P-peak voltage or oscilloscope
: Take the gate pulse current as an example.
4.5.3 Test procedure
GB/T 3790 ... 1995
According to the detailed specifications, add filament and grid voltage to the fluorescent tube, then adjust the anode voltage, make the fluorescent tube glow, then gradually reduce the anode voltage until the fluorescent tube display surface glow just disappears or the brightness of the fluorescent tube display surface drops to 0.3cd/m2, and read the anode cut-off voltage from the anode voltmeter.
4.6 Electrode lead open, electrode lead mis-conduction 4.6.1 Definition
Under the specified working conditions, when the filament is working normally, the anode segment that is not lit due to the open circuit between the electrode and its lead wire is called a broken electrode; the anode segment that is lit due to the electrical connection between the electrodes is called a continuous electrode. 4.6.2 Test circuit diagram
4.6.2.1 Common-grid test circuit diagram is shown in Figure 13, 8
4.6.2.2 Separate-grid test circuit diagram is shown in Figure 2 Note: When testing one bit, the other bits should be added with cut-off voltage. 4.6.3 Test procedure
4.6.3.1 Common-grid test procedure
According to the detailed specifications, apply voltage to the filament of the fluorescent tube and the grid of all bits. When the filament is working normally, apply voltage to each anode segment respectively. Use visual inspection to check that any one that is not lit when powered on is a broken pole; any one that is lit when not powered on is a connected pole. 4.6.3.2 Separate-grid test procedure
According to the detailed specifications, apply voltage to the filament of the fluorescent tube and the grid of all bits. When the filament is working normally, apply voltage to each anode segment respectively. Use visual inspection to check that any one that is not lit when powered on is a broken pole; any one that is lit when powered on is a connected pole. Then disconnect the gate, apply voltage to all the attached electrode segments, and then apply voltage to the gate of each bit respectively. Use the monthly test method to check that those that are powered on but not lit are disconnected poles, and those that are powered on and lit are connected poles.
4.7 Interelectrode leakage current (or insulation resistance of interelectrode)
4.7.1 Definition
A physical quantity that characterizes the degree of insulation between electrodes, which can be expressed as leakage current or insulation resistance value. 4.7.2 The test circuit diagram is shown in Figure 14.
: 1995
GB/I 3790
4.7.3 Test procedure
Connect the A and B terminals in the figure to the two poles of the fluorescent tube to be tested, and add the test voltage specified in the detailed specifications. At this time, the indication value of the microammeter is the leakage current (or converted to insulation resistance value). 4.B Electrostatic induction 4.8.1 Definition
When the fluorescent tube is working normally, it is affected by the external electric field, causing the light parameters to change temporarily. 4.8.2 The test circuit diagram is shown in Figure 15.
P:—Peak electric music meter or oscilloscope
Note that the conductive film on the inner surface of the glass shell has been connected to the filament and the inside of the fluorescent tube. 4.8.3 Test procedure
According to the detailed specifications, apply voltage to each electrode of the fluorescent tube. After the fluorescent tube works normally, turn the measurement conversion switch from 2 to 1, and apply the DC test voltage specified in the detailed specifications to the outer surface of the glass shell. Then turn the measurement conversion switch from 1 to 2, and record the time required for the brightness of the fluorescent tube to return to normal.
4.9 Luminance
4.9.1 Definition
Luminous intensity radiated along the normal direction on the unit area of the luminous surface (see 1.3.6 of GB4597). 4.9.2 Test Schematic
4.9.2.1 The schematic diagram of the luminance meter test device is shown in Figure 16. G
CB/T37901995
P,—luminance meter; P—detector, S. —test area; Gr—power supply 4.9.2.2 The schematic diagram of the illuminance meter test device is shown in Figure 17, P
Photoelectric element
Emitting surface
P, Test attenuation device, P:—detector; G,—power supply: H—distance from luminous surface to photoelectric element2. Electrode test procedure
According to the detailed specifications, apply voltage to the filament of the fluorescent tube and the anode of all digits. When the filament is working, apply voltage to each anode segment respectively. Use visual inspection to check that those that are not energized are disconnected and those that are energized and light up are connected. Then disconnect the grid, apply voltage to all anode segments, and then apply voltage to the grid of each digit respectively. Use the test method to check that those that are energized but not light up are disconnected and those that are energized and light up are connected.
4.7 Interelectrode leakage current (or insulation resistance of inter-electrode)
4. 7. 1 Definition
A physical quantity that characterizes the degree of insulation between electrodes, which can be expressed as leakage current or insulation resistance value. 4.7.2 The test circuit diagram is shown in Figure 14.
：1995
GB/I 3790
4.7.3 Test procedure
Connect the A and B terminals in the figure to the two poles of the fluorescent tube to be tested, and add the test voltage specified in the detailed specification. At this time, the indication value of the microammeter is the leakage current (or converted to the insulation resistance value). 4.B Electrostatic induction 4.8.1 Definition
When the fluorescent tube is working normally, it is affected by the external electric field, causing the light parameters to change temporarily. 4.8.2 The test circuit diagram is shown in Figure 15.
P:—Peak electric music meter or oscilloscope
Note that the conductive film on the inner surface of the glass shell has been connected to the filament and the inner surface of the fluorescent tube. 4.8.3 Test procedure
According to the detailed specification, apply voltage to each electrode of the fluorescent tube. After the fluorescent tube works normally, turn the measurement conversion switch from 2 to 1, so that the DC test voltage specified in the detailed specification is applied to the outer surface of the glass shell. Then turn the measurement switch from 1 to 2, and record the time required for the brightness of the fluorescent tube to return to normal.
4.9 Luminance
4.9.1 Definition
The luminous intensity radiated along the normal direction per unit area of the luminous surface (see 1.3.6 of GB4597). 4.9.2 Test Schematic
4.9.2.1 The schematic diagram of the luminance meter test device is shown in Figure 16. G
CB/T37901995
P,—luminance meter; P—detector, S. —test area; Gr—power supply 4.9.2.2 The schematic diagram of the illuminance meter test device is shown in Figure 17, P
Photoelectric element
Emitting surface
P, Test attenuation device, P:—detector; G,—power supply: H—distance from the luminous surface to the photoelectric element2. Electrode test procedure
According to the detailed specifications, apply voltage to the filament of the fluorescent tube and the anode of all digits. When the filament is working, apply voltage to each anode segment respectively. Use visual inspection to check that those that are not energized are disconnected and those that are energized and light up are connected. Then disconnect the grid, apply voltage to all anode segments, and then apply voltage to the grid of each digit respectively. Use the test method to check that those that are energized but not light up are disconnected and those that are energized and light up are connected.
4.7 Interelectrode leakage current (or insulation resistance of inter-electrode)
4. 7. 1 Definition
A physical quantity that characterizes the degree of insulation between electrodes, which can be expressed as leakage current or insulation resistance value. 4.7.2 The test circuit diagram is shown in Figure 14.
：1995
GB/I 3790
4.7.3 Test procedure
Connect the A and B terminals in the figure to the two poles of the fluorescent tube to be tested, and add the test voltage specified in the detailed specification. At this time, the indication value of the microammeter is the leakage current (or converted to the insulation resistance value). 4.B Electrostatic induction 4.8.1 Definition
When the fluorescent tube is working normally, it is affected by the external electric field, causing the light parameters to change temporarily. 4.8.2 The test circuit diagram is shown in Figure 15.
P:—Peak electric music meter or oscilloscope
Note that the conductive film on the inner surface of the glass shell has been connected to the filament and the inner surface of the fluorescent tube. 4.8.3 Test procedure
According to the detailed specification, apply voltage to each electrode of the fluorescent tube. After the fluorescent tube works normally, turn the measurement conversion switch from 2 to 1, so that the DC test voltage specified in the detailed specification is applied to the outer surface of the glass shell. Then turn the measurement switch from 1 to 2, and record the time required for the brightness of the fluorescent tube to return to normal.
4.9 Luminance
4.9.1 Definition
The luminous intensity radiated along the normal direction per unit area of the luminous surface (see 1.3.6 of GB4597). 4.9.2 Test Schematic
4.9.2.1 The schematic diagram of the luminance meter test device is shown in Figure 16. G
CB/T37901995
P,—luminance meter; P—detector, S. —test area; Gr—power supply 4.9.2.2 The schematic diagram of the illuminance meter test device is shown in Figure 17, P
Photoelectric element
Emitting surface
P, Test attenuation device, P:—detector; G,—power supply: H—distance from the luminous surface to the photoelectric element
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