1、oc-, n EIA TEPLOS BL W 3234600 0007Z70 4 W - FEBRUARY 1981 INDUSTRIAL CATHODE RAY TUBE TEST METHODS FORMULATED BY EIA TUBE ENGINEERING PANEL ADVISORY COUNCIL (TEPAC) TEPAC PUBLICATION No. 105 . - - - I _ - EIA TEP305 81 m 323Yb00 0007293 b m Published by ELECTRONIC INDUSTRIES ASSOCIATION Engineering
2、 Department 2001 Eye Street, N.W., Washington, D.C. 20006 PRICE: $5.00 I EIA TEPLOS BL H 3234b00 0007292 B W INDUSTRIAL CATHODE RAY TUBE TEST METHODS TEPAC PUBLICATION NO. 105 This pub1 ication was formulated under the cognizance of the JT-20 Committee on Electro-Optic Devices and approved by the Tu
3、be Engineering Panel Advisory Counci 1 (TEPAC) PREFACE This publication includes all test methods developed by the JT-20 Committee on Electro-optic Devices for use in testing industrial cathode ray tubes, They are intended to be useful in evaluating cathode ray tubes with respect to parameters which
4、 are of interest to users of these devices. Included in the industrial CRT test methods is the measurement of control electrode voltages (previously issued as TEPAC Pub1 ication No. 97). This publication was compiled by the JT-6.16 Subcommittee on Industrial and Commercial Cathode Ray Tubes and appr
5、oved by the JT-6 Committee on Cathode Ray Tubes and the JEDEC Electron Tube Council, the test methods for industrial CRTS available in one document. e Its inclusion here makes all It is expected that as additional test methods become available, they will be incorporated into future additions to TEPA
6、C Publication 105. It is also expected that, at an appropriate time in the future, this material will be forwarded to the U.S. National Committee (USNC) of the IEC as a proposed revision, in part, of IEC 151-14. -1 - !EIA TEPL05 81 3234600 0007293 T * TEPAC PUBLICATION NO. 105 INDUSTRIAL CATHODE RAY
7、 TUBE TEST METHODS TABLE OF CONTENTS Page TEST METHOD 105-1 MEASUREMENT OF CONTROL ELECTRODE VOLTAGES IN CATHODE RAY TUBE$ . 3 TEST METHOD 105-2 METHOD OF TEST FOR CRT RASTER LUMINANCE 5 TEST METHOD 105-3 METHOD FOR MEASUREMENT OF LINE WIDTH BY THE SHRINKING RASTER METHOD (SRM) . 7 TEST METHOD 105-4
8、 METHOD OF TEST FOR PATTERN DISTORTION . 9 TEST METHOD 105-5 METHOD FOR MEASURING SPOT POSITION . 12 TEST METHOD 105-6 METHOD FOR MEASURING SPURIOUS ILLUMINATION . 14 EIA TEPLOS BL m 3234b00 O007294 L m 1. 1.1 1.2 1.3 1.4 1.5 2. 2.1 Def i n TEST METHOD 105-1 MEASUREMENT OF . CONTROL ELECTRODE VOLTAG
9、ES IN CATHODE RAY TUBES t ,ans Cutoff The cutoff of a CRT is the level of operation below which its output is effectively zero. Cutoff is established by visual extinction of a focused spot (Spot Cutoff), visual extinction of a focused raster of specified size (Raster Cutoff), or a specified Low Cath
10、ode Current Level. cut Off A CRT is cut off when operating at or below the cutoff level. Cutoff Vol tage Cutoff voltage is the voltage between grid and cathode necessary to achieve cutoff; i .e. cathode cutoff, grid 1 voltage relative to cathode for grid 1 cutoff or grid 2 voltage relative to cathod
11、e (unless otherwise stated) for grid 2 cutoff. cathode vol tage relative to grid 1 for Cathode Drive (Modulation) Vol tage The difference between the cathode-grid vol tage required for cutoff and that required for a specified luminance or cathode current. Grid Drive (Modulation) Voltage The differen
12、ce between the grid-cathode vol tage required for cutoff and that required for a specified luminance or cathode current. Test Methods Cutoff Vol tage With all electrode voltages and other operating parameters as speci- fied, adjust and measure the voltage applied to the specified current-regulating
13、electrode (cathode, grid 1 or grid 2) to achieve cutoff. EIA TEPLOS 81 W 3234b00 O007295 3 W 2.2 2.2.1 2.2.2 105-1 Precautions 1. In the measurement of spot cutoff, care must be taken to avoid damage to the screen. It is suggested that current be reduced , to near extinction of a focused raster befo
14、re removing scanning, 2. Unwanted deflections of the beam must be avoided. 3. In the measurement of raster cutoff, scanning must be linear to avoid bright areas. In the measurement of both spot and raster cutoff, light inci- dent on the tube face must be below a specified level. 4. 5. In the measure
15、ment of both spot and raster cutoff in CRTs with very long persistence it may be necessary to use a “cut on“ rather than a “cut off“ technique. In the measurement of cutoff to a predetermined current level, care must be taken to distinguish between beam current and leak- 6. age currents. Modulation
16、Voltages Measurement of Grid Drive (Modulation) Vol tage With all operating conditions as specified, raise the grid voltage from the cutoff value toward the cathode voltage until the specfied luminance or cathode current is achieved. The change in voltage is the grid drive (modulation) voltage. Meas
17、urement of Cathode Drive (Modulation) Vol tage With ail operating conditions as specified, reduce the cathode vol- tage from the cutoff value toward the grid voltage until the speci- fied luminance or cathode current is achieved. is the cathode drive (modulation) vol tage. The change in voltage -4-
18、EXA TEP105 81 m 323qb00 0007296 5 m TEST METHOD 105-2 METHOD OF TEST FOR CRT RASTER LUMINANCE 1. Purpose This method measures the luminous output from the face 0f.a CRT. 2. Test Equipment 2.1 Power supplies meeting the vol t.ages, currents and regulation speci- fied shall be used. 2.2 A calibrated l
19、uminance meter with spectral response closely matched to the CIE photopic curve (response of the average human eye), having sensitivity ranges compatible with the light levels anticipated and calibrated in nits (candelas/meter2) shall be used. of the photometer shall be +5% or better. may also be us
20、ed. A meter for monitoring the total accelerating potential between the cathode and screen with an accuracy of Il% or better shall be used. A meter for monitoring the total beam current delivered to the screen The accuracy (Footlambert calibration Multiply by 3.426 to obtain nits (candelas/meter2) 2
21、.3 O 2.4 with an accuracy of cl% or better shall be used. may be used for CRTs not suitable for measuring beam current.) (Cathode current 2.5 For these measurements a generator capable of producing a raster of 60 frames per second and 100 or more lines shall be used unless otherwise specified. The g
22、enerated raster shall have non1 ineari ty not greater than 5% along each axis. Retrace blanking shall not be area of the raster and large enough to include at least 10 scanning lines. . used. The fieid of view of the photometer should be smaller than the 3. Test Procedure 3.1 The CRT operating condi
23、tions shall be stated. i ncl uded . The following shall be O 31.1 i The incident illumination on the CRT face. EIA TEPLOS BL 3234600 0007297 7 = 105-2 The dimensions of the raster. (The shrinking raster method (SRM) may be used to obtain a measure of the highlight luminance of the written line. sinc
24、e the raster height is automatically satisfied by the me,rger conditions. Focused or defocused. Def 1 ecti on waveform. Location of measurement, Accelerating potential and beam current or equivalents, Vertical and horizontal scan rates. In this case only the raster width should be stated Precautions
25、 Care must be exercised to make certain that the beam current specf-. fied and/or used will not damqge the phosphor. EIA TEPLOS 81 m 3234600 0007298 9 m e TEST METHOD 105-3 METHOD FOR MEASUREMENT OF LINE WIDTH BY THE SHRINKING RASTER METHOD (SRM) 1. 2. 2.1 2.2 2.3 3. 3.1 3.2 3.3 3.4 3.4.1 3.4.2 3.4.
26、3 Purpose The shrinking raster resolution measurement is a method of obtain- ing the effective resolution of a tube where a relatively fast, low cost method with reasonable accuracy is required. Test Equipment Power supplies meeting the voltages, currents, and regulation speci- fied shall be used, A
27、 scan generator capable of generating a raster of lines (for example, 100 lines at 60 Hertz) at a rate greater than the flicker frequency of the eye. pendicular to the scanned lines must be as linear as possible and the line retrace shall be blanked, or as may be otherwise specified. Interlaced rast
28、ers should not be used. The test shall be conducted in facilities which can be arranged to meet the illumination conditions specified. The deflection linearity along the axis per- Test Procedure The CRT shall be operated at the conditions specified. The incident illuminance on the tube face shall be
29、 specified. Adjust the CRT voltages, currents, or luminances as specified. If not otherwise specified, the focus voltage (or current) shall be determined as follows. Adjust the focus voltage (or current) for optimum focus at the screen center. Repeat 3.4.1 with the raster rotated 90 degrees. Average
30、 the results obtained in 3.4.1 and 3.4.2 to determine center focus 9 EIA TEPLOS 81 3234b00 0007299 O 3b4.4 3.5 .3,6 3b7 3b8 4. 4.1 4.2 5. 5.1 5.2 105-3 e In applications where changing the axis of the raster is not practical, the center focus may be determined by pulsing a dot pattern or an undeflec
31、ted spot to the required drive level. will be considered optimum when the smallest round spots are generated. screen burn. Focus Pulse duty cycle must be sufficiently low to avoid At the specified electrode voltages and/or currents the raster shall be expanded initially to show spaces between the li
32、nes. Without changing the line length, the line-to-line spacing shall be diminished until the line structure first disappears at the screen center. The shrinking raster line width is determined by dividing the com- pressed raster height by the number of scanned lines. Without changing focus (unless
33、otherwise specified) repeat 3.5 through 3.7 to determine the resolution at the other specified location(s). Precautions It is important in step 3.6 to obtain the condition at which the line structure first merges. produce a pseudo line structure appearance which can again be merged by still further
34、shrinking. Any condition except the first merge will yield false resolution data. If a dot or dot pattern is used to adjust focus, care must be exercised to avoid screen burn by adjusting the pulse duty cycle. Further shrinking of the raster may Special Parameters To Be Specified The incident illumi
35、nance of the unexcited screen shall be specified. The line length at which the resolution test is to be performed shall be specified. -8- EIA TEPLOS 81 m 3234600 0007300 3 m TEST METHOD 105-4 1. 2. 2.1 2.2 22.1 O 2.2.2 METHOD OF TEST FOR PATTERN DISTORTION Purpose This method measures the pattern di
36、stortion .in percent of the scar at a specified percentage of the minimum useful scan of the tube. It includes the total errors of the deflection distortions arising from trace angle, keystone, pin cushion, and barrel effects. Test Equipment Power supplies meeting the voltages, currents, and regulat
37、ion specified shall be used. A transparent overlay on which are. two concentric rectangles and two cross 1 i nes bisecting the rectangles and mutual ly perpendicul ar to their sides shall be used. The sizes of the two rectangles shall be computed as follows: The size of the scan at which the determi
38、nation of pattern distor- tion is to be made shall be computed by multiplying the dimension of the minimum useful scan of each axis by the percentage of scan at which the pattern distortion test is to be made. the dimensions of the inner rectangle. The dimensions of the inner rectangle shall be mult
39、iplied by the maximum allowable percentage of pattern distortion. Each side of the outer rectangle shall be displaced from the edge of the inner rectangle by this computed amount, Example: A cathode-ray tube has a minimum useful scan of 4 inches on 1D2 and 3 inches on 3D4. Pattern distor- tion shall
40、 be less than 2 percent at 75 percent of useful scan. Inner rectangle dimensions, therefore, are These shall .be 75% x 4“ = 3“ 75% X 3“ = 2.25“ 3“ X 2.25“ 2% X 3“ = 0.060 2% X 2.25“ = 0.045“ Outer rectangle dimensions are 3 + 2(0.060) = 3.12“ by 2.25 + 2(0.045) = 2.34“ -9- EIA TEP105 AL 3234b00 O007
41、301 5 W d 3. 3.1 . 3.1.1 3.1.2 3.1.3 3.1.4 3.1.5 3.1.6 3.1.7 3.1.8 3.2 105-4 Test Procedure Method A (Electrostatic Deflection Tubes) The CRT shall be operated at the conditions specified. The overlay shall be fixed in position with respect to the tube face with the center of the rectangles at the c
42、enter of the tube face, or as specified, and with a trace produced by the 1D2 deflection plates aligned with the cross line parallel with the 1D2 scan dimension of the overlay, and approximately equal to it in length. With balanced dc voltages on the 3D4 deflection plates, the trace shall be moved o
43、ut alternately to both edges of the overlay pattern. At some given trace position the entire length of the trace shall fall within the two boundaries which are parallel to the 1D2 axis at the two edges of the rectangles. Note: The center of the trace shall be used in this measurement. Reposition the
44、 trace to pass through the center of the tube. CAUTION: Grid/cathode drive must be reduced to avoid burning the phosphor until the trace of Step 3.1.6 is displayed. Without repositioning the overlay, the trace produced by the 1D2 deflection plates shall be interchanged with one produced by the 3D4 d
45、eflection plates. Repeat steps 3.1.3 and 3.1.4 with 1D2 and 3D4 interchanged in the step procedures. The traces developed by steps 3.1.2 through 3.1.7 shall fall within the inner and outer rectangles of all four sides of the over1 ay. Method B (Electromagnetic Deflection Tubes) (To be developed) -1
46、0- EIA TEPLOS BL m 3234b00 0007302 7 m 105-4 4. 4.1 e 4.2 4.3 5. 5.1 5.2 5.3 Precautions The measurements with a single layer overlay are susceptible to error by parallax, especially in CRTs with thick or non-planar face plates. Care must be exercised to avoid a shift in viewing angle which wi 11 pr
47、oduce erroneous measurements. It is recommended, where practical, that a thick transparent overlay appropriately scribed on both surfaces be used to avoid parallax errors. The width of the trace in this measurement is not a criterion. The center of the trace only shall determine the acceptability or
48、 rejection of the CRT. Care must be exercised to reduce beam current to a value which will not produce phosphor burn. Special Parameters To Be Specified The use of a single layer or double layer (parallax-free) trans- parency s ha1 1 be specified. The size of the pattern at which distortion is to be
49、 measured shall be specified. The percentage of distortion shall be specified. -9 1- 1. 2. 2.2 3. 3.1 3.1.1 3.1.2 3.1.3 3.1.4 3.2 3.2.1 3.2.2 3.2.3 EIA TEPLOS 81 3234600 0007303 7 * TEST METHOD 105-5 METHOD FOR MEASURING SPOT POSITION Purpose To determine the undeflected spot position of the electron beam in a CRT. Test Equipment Power suppl ies meeting the voltages, currents, and regulation specified shall be used. Measuring instruments, overlays, and/or optical aids may be used as required to obtain the accuracy of measurement specified. Test Procedure Method A (Elec
