1、b, - EIA TEPLOS-8 87 m 3234600 0007383 O m - .- -5s . 00 I u3 O E t TEPAC PU B L I CAT I ON Raster Response Measurement for Monochrome Cathode Ray Tubes TEP105-8 JANUARY 1987 ELECTRONIC INDUSTRIES ASSOCIATION ENGINEERING DEPARTMENT EIA TEPL05- ? 3234600 0007384 2 NOTICE IA Engineering Standards and
2、Publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particu
3、lar need. Existence of such Standards and Pub- lications shall not in any respect preclude any member or non-member of EIA from manufacturing or selling products not conforming to such Standards and Publications, nor shall the existence of such Standards and Publications preclude their voluntary use
4、 by those other than EIA members, whether the standard is to be used either domestically or internationally. Recommended Standards and Publications are adopted by EIA without regard to whether or not their adoption may involve patents on articles, materials, or processes. By such action, EIA does no
5、t assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Recom- mended Standard or Publication. Published by ELECTRONIC INDUSTRIES ASSOCIATION Engineering Department 2001 Eye Street, N.W. Washington, D.C. 20006 PRICE: $5.00 Published in U.S.A. c
6、7 EIA TEPL05-8 87 3234b00 0007385 4 W INDUSTRIAL CATEOIBE RAY TOBE TEST HEXE00 105-8 This publication was formulated under the cognizance of the JT-20 Committee on Electro-Optic Devices and approved by the Tube Engineering Panel Advisory Council (TEPAC). developed for industrial cathode ray tubes. u
7、seful in evaluating cathode ray tubes with respect to parameters which are of interest to users of these devices. It is expected that, at an appropriate time, this material will be forwarded to the US National Committee (USNC) of the IEC as a proposed revision, in part, of IEC 151-14. The TEP-105 se
8、ries of publications comprise a set of test methods They are intended to be i EIA TEPLOS-8 87 m 3234600 0007386 6 m .= =4 TEP 105-8 Page 1. RASTER RESPONSE MEASUREMENT FOR MONOCHROME CATHODE RAY TUBES 1.0 SCOPE The purpose of this test is to measure the resolution capability of a cathode ray display
9、 tube. Raster scan is the most widely used method of displaying information on a CRT. figure of merit related to the resolution of the display tube. The resolution is dependent on: The test described in this section gives a 1. The electron beam distribution as it is focussed onto the phosphor screen
10、. Electron scatter and light scatter due to the granular nature of the phosphor and the aluminum backing of the screen 2, 3. Saturation of the phosphor. 4. Internal reflections within the faceplate and panels mounted onto the faceplate. 5. Optical effects of coatings, etchings, etc., on the faceplat
11、e and panel. Other external influences including ambient light are not addressed in this method. of the viewing system are not considered. As well, the transfer characteristics 2. O TEST EQUIPMENT 2.1 Power supplies are required to operate the cathode ray tube under the specified conditions of volta
12、ge, current and regulation. 2.2 Deflection supplies providing linear sweeps in each deflection coil axis are required to generate the scan lines to be measured. The supply should be capable of producing the scan rate and repetition rate as specified for the cathode ray tube. EIA TEPL05-8 87 m 323460
13、0 0007387 8 m TEP 1 O 5 -8 Page 2 2.3 A slit scan analyzer consisting of optics, slit or aperture, detector (single or multiple), and the necessary power supply and amplifier for the detector must be provided. The sensitivity and spectral response of the detector should be matched to the final use o
14、f the CRT, e.g. human observer, film recording. should be used when the application is a human observer. Complete units, listed alphabetically, available from Celco, Gamma Scientific, Microvision, and Photo Research, (or equivalent) may be used. An oscilloscope or chart recorder is usually necessary
15、 to display the trace profile. The test should be conducted in facilities where ambient light levels can be reduced adequately to prevent interference with the measurements. ambient light should be less than one percent of the peak intensity, i3max. A photopic detector 2.4 2.5 The background or 3.0
16、TEST SETUP 3.1 The CRT shall be operated at the conditions specified. They shall include all tube electrode voltages as well as an operating condition based on either drive, current, luminous output or radiant output. Deflection parameters such as yoke type, raster size, writing speed, retrace blank
17、ing interval and repetition rate shall be specified if applicable. Specifications should realistically represent the conditions of use of the CRT. 3.2 To prevent the maximum allowable power dissipation in the CRT being exceeded, the raster may be displayed at a selected duty cycle less than 100 perc
18、ent. The slit scan analyzer should be oriented such that the scan lines are imaged onto the slit parallel to the slit typically within one degree. selecting the slit width and imaging lens magnification such that a sufficiently narrow area of a scan line is imaged. amplitude is being recorded. slit
19、width be a maximum of one tenth of the projected scan line image in the plane of the slit. On high light output tubes one must be careful to operate the detector in a linear response mode. accomplished through the use of neutral density filters or a variable aperture objective lens. diffraction limi
20、t of the lens when using small apertures. 3.3 Care should be taken in This will assure that a more accurate peak It is recommended that the This may be Do not exceed the v- 3 EIA TEPL05-8 87 W 3234600 0007388 T W TEP105-8 Page 3 3.4 The raster response measurement is generally performed at the cente
21、r of the tube face. It may, however, be desirable to perform the measurements at the edges, corners or other locations on the CRT-face. measure horizontal as well as vertical resolution by either rotating the deflection yoke 90 degrees for center measurements or by interchanging the vertical and hor
22、izontal deflection signals for all screen locations. It may also be advisable to 4.0 TEST PROCEWRE 4.1 The technique involves displaying a specified number of active scan lines on the CRT face and controlling the line spacing to achieve various spatial frequencies. frequency is defined as the number
23、 of active scan lines per unit length. perpendicular direction to the scan lines such that the light pickup device reads the peak intensity of the scan lines as well as the nulls between lines. Do not exceed the slewing rate of the detector, chart recorder or other output device. Spatial A slit or a
24、perture is traversed in a 4.2 A plot or graphic representation is recorded of the peaks and nulls. calculated by the formula: The percentage raster response is then XRR = Bmax - Bmin x 100 6 max Where 6 max = peak intensity of raster line B min = null intensity between raster lines. % RR = percent r
25、aster response 5.0 DATA 5.1 A minimum of two levels of raster response should be measured corresponding to two respective spatial frequencies. 50 percent. The two recommended levels are 10 percent and 5.1.1 An alternative method may be used in which a fixed spatial frequency is specified and the res
26、ulting raster response is measured. 5.2 For each raster response measured at each position on the face of the tube, two measurements should be made - one for horizontal raster lines and one with vertical raster lines. EIA TEPL05-8 87 3234600 0007389 L m TEP105-8 Page 4 5.3 The method of focusing the
27、 CRT must be clearly and completely specified. 6. O PRECAUTIONS 6.1 6.2 6.3 6.4 6.5 6.6 Be careful not to saturate the photodetector system such that its response becomes non linear. The operator must confirm that the raster lines are not over-merged. line spacing and assuring that the raster respon
28、se monotonically increases. this is sufficient. This can be accomplished by increasing the Usually, a visual confirmation of Focussing the image of the slit or aperture onto the CRT image is critical and should be adjusted for the highest peak intensity reading. If a slit is used it must be carefull
29、y aligned such that its major axis is parallel to the direction of line scan typically within one degree. Measurements are dependent on the quality of the deflection yoke, particularly at locations other than the center of the tube face. Although not specified in this document, the following items s
30、hould be considered as they affect the accuracy and repeatability of the measurements: 1. Power supply stability and accuracy. 2. Deflection and video jitter. 3. Mechanical stability of setup. 4. Magnetic, electromagnetic and electrostatic fields in the area of the CRT including those from corrective devices on the CRT or yoke. O a
