1. An inspection apparatus comprising:
an inspection-signal supply terminal adapted to be disposed on one of the surfaces of a circuit board formed with a plurality of conductive patterns to be inspected, said conductive patterns being arranged such that the contact terminals of said conductive patterns are disposed parallel to each other, and arranged at a fine pitch with the distance between each of said conductive patterns being equal, so as to supply an inspection signal to each of said conductive patterns therethrough, said inspection-signal supply terminal having a width equal to or less than that of the layout pitch of said conductive patterns;
scanning means for scanningly moving said inspection-signal supply terminal across and inspection-signal supply region including respective portions of said conductive patterns; from each of said conductive patterns in response to said inspection signal supplied from said
a sensor section adapted to be disposed on the other surface of said circuit board of at least at a position opposed to said inspection-signal supply terminal so as to detect a signal from each of said conductive patterns in response to said inspection signal supplied from said inspection- signal terminal to each of said conductive patterns, said sensor section having a width equal to or greater than that three times greaterr than the layout pitch of said conductive patterns;
signal control means for feeding the inspection signal to said inspection-signal supply terminal being scanningly moved by said scanning means, and picking up the detected signal from said sensor section disposed on the other surface of said circuit board; and
determination means for determining if each of said conductive patterns supplied with the inspection signal includes a short-circuit, according to whether the level of said detected signal picked up by said signal control means is different from a signal level in a normal state.
2. The inspection apparatus as defined in claim 1, wherein said sensor section is an electrode with a surface having an area capable of entirely covering the other surface of said circuit board corresponding to said inspection-signal supply region of said conductive patterns, wherein said electrode is adapted to be fixedly positioned in a capacitive coupling relationship with said conductive patterns serving as corresponding electrodes, so as to detect the signal from each of said conductive patterns.
3. The inspection apparatus as defined in claim 1, wherein if one of said conductive patterns provides a signal level exceeding a threshold greater than a signal level to be detected by said sensor section when said one conductive pattern is independent of any other conductive patterns, said determination means is operable to determine that said one conductive pattern is short-circuited to the conductive pattern adjacent thereto.
4. The inspection apparatus as defined in claim 2, wherein if one of said conductive patterns provides a signal level exceeding a threshold greater than a signal level to be detected by said sensor section when said one conductive pattern is independent of any other conductive patterns, said determination means is operable to determine that said one conductive pattern is short-circuited to the conductive pattern adjacent thereto.
5. An inspection method for use with an inspection apparatus including an inspection-signal supply terminal having a width equal to or less than that of the layout pitch of conductive patterns formed in a circuit board, said conductive patterns being arranged such that the contact termainals of said conductive patterns are disposed parallel to each other, and arranged at a fine pitch with the distance between each of said conductive patterns being equal and a sensor having a width equal to or greater than that three times greater than the layout pitch of said conductive patterns, said method comprising:
disposing said inspection-signal supply terminal on one of the surfaces of said circuit board and scanningly moving said inspection-signal supply terminal across an inspection-signal supply region including respective portions of said conductive patterns to supply an inspection signal to each of said conductive patterns therethrough, while disposing said sensor section on the other surface of said circuit board at least at a position opposed to said inspection-signal supply terminal to detect a signal from each of said conductive patterns in response to said inspection signal supplied from said inspection-signal supply terminal to each of said conductive patterns; and
picking up the detected signal from said sensor section, and determining if each of said conductive patterns supplied with the inspection signal includes a short-circuit, according to whether the level of said detected signal is different from a signal level in a normal state.
6. The inspection method as defined in claim 5, wherein said sensor section is an electrode with a surface having an area capable of entirely covering the other surface of said circuit board corresponding to said inspection-signal supply region of said conductive patterns, wherein said electrode is fixedly positioned in a capacitive coupling relationship with said conductive patterns serving as corresponding electrodes, to detect the signal from each of said conductive patterns.
7. The inspection method as defined in claim 6, which includes determining that, if one of said conductive patterns provides a signal level exceeding a threshold greater than a signal level to be detected by said sensor section when said one conductive pattern is independent of any other conductive patterns, said one conductive pattern is short-circuited to the conductive pattern adjacent thereto.
8. The inspection method as defined in claim 5, which includes determining that, if one of said conductive patterns provides a signal level exceeding a threshold greater than a signal level to be detected by said sensor section when said one conductive pattern is independent of any other conductive patterns, said one conductive pattern is short-circuited to the conductive pattern adjacent thereto.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A process for preparing 2,3,3,3-tetrafluoropropene (1234yf), comprising:
(i) contacting 1,1,2,3-tetrachloropropene (1230xa) with hydrogen fluoride HF in the gas phase in the presence of a fluorination catalyst under conditions sufficient to produce a reaction mixture;
(ii) separating the reaction mixture into a first stream comprising HCl and 2,3,3,3-tetrafluoropropene (1234yf), and a second stream comprising HF, 2-chloro-3,3,3-trifluoro-1-propene (1233xf), and 1,1,1,2,2-pentafluoropropane (245cb); and
(iii) recycling at least a part of the second stream back to step (i).
2. The process of claim 1, wherein the reaction mixture obtained in step (i) comprises 2,3,3,3-tetrafluoropropene (1234yf) and 1,1,1,2,2-pentafluoropropane (245cb) in a molar ratio ranging from 1:5 to 3:1.
3. The process of claim 2, wherein the reaction mixture obtained in step (i) comprises 2,3,3,3-tetrafluoropropene (1234yf), 1,1,1,2,2-pentafluoropropane (245cb), and 1,1,1,2-tetrafluoro-2-chloropropane (244bb), wherein the molar ratio of 245cb to 244bb ranges from 1:1 to 70:1.
4. The process of claim 1, wherein the molar ratio of HF to 1230xa in step (i) ranges from 3:1 to 150:1.
5. The process of claim 1, wherein step (i) is carried out at a pressure ranging from 3 to 20 bars.
6. The process of claim 1, wherein step (i) is carried out at a temperature ranging from 200 to 450\xb0 C.
7. The process of claim 1, wherein step (i) is carried out with a contact time ranging from 6 to 100 sec.
8. The process of claim 1, wherein step (i) is carried out in the presence of O2 andor Cl2.
9. The process of claim 8, wherein the ratio of O2 andor Cl2 to 1,1,2,3-tetrachloropropene (1230xa) ranges from 0.05 to 15 mole %.
10. The process of claim 1, wherein step (ii) comprises a distillation.
11. The process of claim 1, further comprising separating the first stream into HCl and 2,3,3,3-tetratluoropropene (1234yf).
12. The process of claim 1, wherein step (i) is carried out in the presence of a polymerization inhibitor.
13. The process of claim 12, wherein the polymerization inhibitor comprises p-methoxyphenol, t-amylphenol, limonene, d,1-limonene, a quinone, a hydroquinone, an epoxide, an amine, or a mixture thereof.
14. The process of claim 1, wherein the fluorination catalyst comprises a catalyst comprising Ni\u2014Cr.
15. The process of claim 1, wherein the fluorination catalyst is supported on a support comprising fluorinated alumina, fluorinated chromia, fluorinated activated carbon, graphite carbon, or a mixture combination.
16. The process of claim 1, wherein the fluorination catalyst comprises a chromium catalyst.
17. The process of claim 1, wherein the fluorination catalyst comprises a co-catalyst selected from Ni, Co, Zn, Mn, Mg, or a mixture thereof.
18. The process of claim 17, wherein the amount of the co-catalyst ranges from about 1 to 10 wt % of said fluorination catalyst.
19. The process of claim 1, further comprising activating the fluorination catalyst with a fluorine-comprising compound.
20. The process of claim 1, wherein said process is continuous.