1、t IUL-F-2l241 (ETOrd) IVAVORD OS 1650 8 October i948 MILITARY SPECIFICATION FILTERS, COLOR, FINISHED (FOR OPTICAL IIGWRUMEHTS) 1. SCOPE 1.1 Scope. - This specification covers finished color filters for use in optical instruments. filters. It is not intended to cover polarizing 1.2 Classification. -
2、Filters shall be of “crie following types, colors, and grades, as specified (see 6.2): Types: Type I - Solid glass. Type II - Laminated. Colors: Red. Yellow. Aircraft neutral. Light neutral. Dark neutral. Searchlight neutral. Grades: Grade A - Adequate for use near the focal plane of an eyepiece. Gr
3、ade BT - Adequate for use near a telescope objective lens. Grade BR - Adequate for use near a rangefinder objective lens. Grade C - Adequate for use at unit magnification, or with the unaided eye. 2. APPLICABIX DoCWmNTS 2.1 The following documents of the issue in effect on date of invitation for bid
4、s form a part of-this specification. F THIS DOCUMENT CONTAINS a Water Va2orproof, Flexible. ML-3-10377 - Boxes, Veneer, Paper, Covered MIL-L-10547 - Liners, Case Miz-STD-lO5 - Sampling Procedures and Tables for Inspection by Attributes MiL-STD-l - Marking for Shipment and Storage BUIIEAU OF ORDIWCE
5、List of drawings arid drawings called for on the applicable scheduie or contract or order (see 6.2). PUBLICATIONS BUREAU OF ORDNANCE: OP 400 - General. Instructiong for the Design, Mariufacture, asid Inspection OP NavL Ordiaance Equipment. Provided by IHSNot for ResaleNo reproduction or networking p
6、ermitted without license from IHS-,-,-(Copies of specifications, standards, drawings, and publications required by contractors in connection with specific procurement func- tions should be obtained from the procuring activity or as directed by the contracting officer) 3. REQUIREbEHTS 3.1 Preproducti
7、on sanple. - Unless otherwise specified in the contract or order (see 6.2), a preproduction sample is required (see 4.3.1) for each type, color, grade, and size filter called for in the contract or order. Samples shall be manufactured using the methods, procedures, and plant location proposed for th
8、e production lot. Samples shall be inspected as specified under 4.4.4.1, such inspection being for the purpose of determining that the manufacturers production process will produce filters that will meet the requirements of this specification. gf preproduction inspection of filters failing to meet d
9、l requirements of ais specification shell be borne by $he contraictor, Costs 3.2 Viterial and construction. - Type I filters shall consist of a single homogenous plate of stable, non-hygroscopic glass. Type II filters shall consist of a single sheet of colored plastic bonded between two plates of co
10、lorless, stable, non-hygroscopic glass. Filters differing in construction as specified above tKl1 be considered for procurement by the procuring activity. difference in construction before submittal of bids. Approval by the procuring activity must be obtained for such 3.3 be as specified on the appl
11、icable drawings. Shape and dimensions. - The shape and dimensions of filfiers shall 3.4 Color. - 3.4.1 Comparison standards (standard filters). - 3.4.1.1 Filter sets. - For each color of production filters required by the contract or order, the contractor shall furnish the Government inspector a set
12、 of four filters, except as provided for in 3.4.1.5, as color comparison standards. the same as the color requirements specified herein for the production filters that each set of standard filters represents. curves of a set of filters shall be simi1a.r in every respect consistent with specified val
13、ues. Two filters of each set shall have a luminous transmittance equal to the maximum value that any filter of a particular color of production filters furnished under a contract will have and the other tio filters shall have the minimum value that any production filter will have (see 6.3). The colo
14、r requirements of each set of standard filters shall be The spectral transmittance 3.4.1.2 - Data. - Eannce is smaller . Tne 3,5,2.2 Definition. - The definition of a telescope of applicable magni- fication shall not be impaired in any manner when the filter is tested as described in 4. h. 4.3.4.2.2
15、. 3.5.2.3 Deviation. - The deviation at normal incidence shall not exceed 3-1/2 minutes OS am. 3.5.3 Grade BT fllters. - 3.5.3.34 Surface and internal defects, - There shall be no surface or interna2 defects visible over the entire area of the filter Ikten the filter is examined as described in 4.4.
16、4.3.4.3.2. 3.5.3,2 DefiniLion, parallax, and resolution. - The definition of a telescope of applicable magnification shall not be impaired in any manner when the filter is tested as described in 4.4.4.3.4.3.2. In addition, no visible pma;LJax between the target image and the telescope crossline shal
17、l be introduced under the conditions of the test, The limit of resolution sha21, not exceed the applicable value when the filter is tested as described in 4.4.4.3.4. 3* 2. 3.5*3.3 Deviation. - The deviation at normal incidence shall not exceed 10 seconds of am. 3.5.4 Grade BR filters. - 3.5.4.1 Surf
18、ace and internal defects. - There shall be no surface or internai defects visible over the entire area of the filter when the filter is exainlned as described in 4.4.4.3,4.4. 3,5,4.2 Definition, parallax, and resolution. - The definition of a telescope of applicable magnification shall not be impair
19、ed in any manner when the filter is tested as described in 4.4.4.3.4.4.2. In addition, no vifiible parallax, between the target image and the telescope crossline, shall be introduced under the conditions of the test. The 13.mi.t of resolution shaI.1 not exceed the applicable value when the filter is
20、 teste6 as described in 4.4,4,3.4.4.2. 3.5.4.3 Dev5,ation. - The deviation at normal. incidence shd.1 not exceed 10 seconds of am. 3.5.5 Grade C filters. - Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-9 Provided by IHSNot for ResaleNo reproduction
21、 or networking permitted without license from IHS-,-,-3.8 General stability to weathering. - The stability shall be such that ilhen the filter is exposed to accelerated weathering conditions in accordance with 4.k,4,lti, no discoloration, separation, or bubble shall extend more than 2 millimeters in
22、 from the eae, remain essentially uniform over the entire area to within 2 millimeters of the edge, md the spectral transmittance at any wavelength shall not have charged by more than LO-percent of the original value. In addition, the color of each ssecimen shall 3.9 Str.ewth of bonding (%ve II filt
23、ersr. - The strength of bonding shall be such that when Vne filter is exgosed to variations of temperature in accordance with 4. 4.4.1. 2, no discoloration, sep.ration, or bubble shall extend more than 2 millimeters in from the ege. n addition, the color shall remain essentially uniform over-the ent
24、ire area to within 2 millimeters of the edge, and the luminous transmittance shall not have changed by more than 10- percent of its original value. 3.10 Worlatianship. - Iorlimanship shall be of such quality as to produce filters of uniform high quality and as to meet all requirements of the applica
25、ble drawings and this specification. 4. 4.1 Unless otherwise specified herein the supplier is responsible for the QUALITY ASSWfCE PROVISIO1JS AIJD TEST REQIREhEXXCS performance of all inspection requirements prior tm submission for Government inspection and acceptance. utilize his own facilities or
26、any commercial laboratory acceptable to the Government, complete and available to the Government as specified in the contract or order, of the same type, color, grade, and size made from one melt, pressing, or batch as applicable , Ekcept as otherwise specified, the supplier may nspection records of
27、 the examinations and tests shall be kept 4.2 Lot. - For purposes of sampling a lot shd.1 consist of all the filters -ii 4.3.2 For preproduction inspection. - Unless otherwise specified (see 4.3.1.l.), three preproduction sample filters shall be supplied by the con- tractor for each type, color, gra
28、de, and size being pinchased. shall be submi.t;ted to the Government inspector for preproduction inspection at an activztty designated in the contract or order (see 6.2) or by the Bureau.of Ordnance. prior to the approval of the procuring activity or completion of inspection on the preproduction sam
29、ples shall be at the contractors risk. production samples will become the property of the procuring activity and will not be Included in the quantity of,filters called for in the contract Samples Further production of the filters by the contractor Pre- or order . 10 Provided by IHSNot for ResaleNo r
30、eproduction or networking permitted without license from IHS-,-,-Provided by IHSNot for ResaleNo reproduction or networking permitted without license from IHS-,-,-IXL-F-2l.241 (ITOrd) 4.4.3 Cleaning, wrapping, packamcea, accelereted weathering under conditions outlined in Eetliod Ilo. 60u or 6022 pe
31、rmitted subject to the appoval of the prociring activity. pletion of the test examine the filters and remeasure spectral transmittances. Heasre spectral Expose the filters lor Ort least 168 hours (one week) to * OP Specification L-P-406. Other means of accelerated weathering may be pon com- 4.4.4.1.
32、2 Strength of bonding (type II filters), - Type II preproduction filters shall be tested for strength of bonding to determine conformance to 3.9. procedures of 4.4.4.3.2 prior to conducting this test. in an oven and maintain the temperature of the oven at plus 155OF for at leafit 5 hours. to rooin t
33、emperature, the temgerature of the chamber maintained at minus 20% for at least 16 hours. Remove the filters fromthe chatriber and allow them to return to roomteqerature, Mter they have returned to room temperature, the filters shall be examined for conformance to 3.9. Luminous transmittance shall b
34、e redetermined in accordance with the procedures of 4.4.4.3.2. Lmxinous transmittance shall be determined in accordance with the Place the filters Remove the filters from the oven and allow them to retun The filters shall then be placed in a cold chaniber and 4.4.4.2 Periodic tests (type II filters)
35、. - Periodic tests shall be performed on ty-ge 11 PiAters and shall consist of the tests of 4.4.4.1.1 and 4.4.4.1.2. 4.h.4.3 Lot acceptance tests. - 4.1i4.3.1 for spectral transmittance to determine conformance “Co 3.4.2.2.1 and 3.4.2.3.1, respectively. able spectrophotometric equipment of adequate
36、sensitivity and resolving power. Spectral- transmittance. - Red and yellow filters shall be tested The test shall be made with a spectrophotometer or other suit- 4.4.i?er light source of equivalent intensity alternately through the filter under test and the light md dark comparison standards. colora
37、tion of the filter shall lie withinhe limits established by viewing the same source through the comparison standards. The test shall consist of viewing the sun or a high intensity The included in the tests. 4.4.4.3.4.1.1 Surface and internal. defects. - Filters shall be examined for surface and inte
38、rnal defects to detemnine conformance to the requirements of the a2plicable grade in 3.5. Except as specified herein examination shall be made with the level of illumination high enough to render any and all defects plainly visible. focal-length with a minimum apparent field of 45 degrees and shall
39、have a reticle or the image of a reticle in a fixed position at the normi. focal plane of the eyepiece. the observers eye. during these tests. The eyepiece shall be 40 plus or minus 2 millimeter equivalent- The eyepiece shall be focusable to allow for correction of The observers vision shdlbe fixed
40、on the reticle 4.4.4.3.4,i. 2 Definition, parallax, and resolution. - Definition, parallax, and resolution tests shall be made by holding the filter in front of the ob- jective of a telescope that has been accurately focused on the target before insertion of the filter and is not refocused duri= the
41、 test. Red filters or eyepiece when focusing to compensate Tor chromatic aberration of the telescope. The target for the definition and parallax tests shall be a round, sharply defined disc illuminated from the rear by tungsten light having a brightness equivalent to the surface of a comercial100 wa
42、tt, 115 volt inside frosted lap operated at line voltage. The diameter of the disc is not critical. A recommended value is approximately i80 seconds of arc ivided by the magni- fication of the testing telescope. The target for the resolution test shall be of the Foucault resolving-power pattern cont
43、aining horizontalie testLw telescope shall be not less than 0.2 of tlie diameter of the filter or clew aperture, whichever is applicable, measured in milimeters or a value OP 6, whichever is greater. Filters shall be tested in accordance 4.4.4.3.4.2,3 Deviation. - Filters shall be tested for deviati
44、on to etermine conTormance to 3.5.2.3. k.404.3.4.3 Grade BT filters. - k.4.4,3.4,3.1 Surface and internal defects, - Filters shall be examined for surface and internal defects to determine conformance to 3.5.3.1. Exami- nation shall be made by means of a 40 millimeter focal-length eyepiece, with tho
45、 filter being placed within 12 millimeters of the focal plane on the side osposite the eyepiece, 4,t,4.3.4.3.2 Definition, pamllax, .and resolution, - Fiters shall be Filters shall be tested in accordance with the procedures in The magniilication of the testing telescope shall be not tested for defi
46、nition, parallax, and resolution to determine conformance to 3.5.3.2. 4.4.4,3.4.1.2. lesc .1;1iw. 0.8. of the diameter of the filter or clear aperture, whichever is applicable, measured in millimeters. met is determined from the following rule; when the iameter of the filter or the diameter of the c
47、lear aperture in the case of beveled filters is less than 35 millimeters, the limit of resolutkm shall be the next whole nuniber above the quotient obtained by dividing 140 seconds of arc by the diameter of the filter or the dimeter of the clear aperture, whichever is applicable, Hhen the dimeter of
48、 the filter or the dianeter of the clear aperture in the case of beveled filters is 35 to 70 millimeters, the limit of resolution chal1 be the next half number above the quotient obtained by divilw 140 seconds ! ! p- Provided by IHSNot for ResaleNo reproduction or networking permitted without licens
49、e from IHS-,-,-MIL-F-21241 (Kord) 4.4.4.3.4.3.3 Deviation. - Filters shall be tested for deviation to determine conformance to 3.5.3.3. 4.4.4.3.4.4 Grade BR filters. - 4.4.4.3.4.4.1 Surface and internal defects. - Filters shall be examined for surface and internal defects to determine conformance to 3.5.4.1. nation shall be mzde by means of a 40 millinieter focal-length eyepiece wTth Yi?e filter Beiw placed withiri 30 millimeters of the Ioc
