1. Motioning equipment for electron column comprising:
the electron column for emitting electron beam on a sample;
a chamber for receiving the electron column and maintaining the electron column in an ultra-high vacuum;
a support for supporting the chamber;
a driving means for driving the support to move the electron column in real time;
the sample on which the electron beam emitted from the electron column is irradiated; and
a vacuum chamber for maintaining the sample in a low or high vacuum.
2. The motioning equipment according to claim 1, wherein the support is further attached with means for providing at least one of vertical motion and tilting to each microcolumn in real time.
3. The motioning equipment according to claim 1, further comprising a rotating plate for rotating the sample.
4. The motioning equipment according to claim 1, wherein the chamber is coupled to an external pumping apparatus through flexible tubes to maintain an ultra-high vacuum.
5. The motioning equipment according to claim 2, further comprising a rotating plate for rotating the sample.
6. The motioning equipment according to claim 2, wherein the chamber is coupled to an external pumping apparatus through flexible tubes to maintain an ultra-high vacuum.
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. Scale reading apparatus comprising:
a scale and readhead moveable relative to one another, said scale having scale markings arranged to form a first incremental pattern having a first scale pitch and at least one scale marking arranged to form a second incremental pattern having a second scale pitch, different to said first scale pitch;
first detecting means to detect said first incremental scale pattern;
second detecting means to detect said second incremental pattern;
wherein both first and second detector means are provided in the same readhead.
2. Scale reading apparatus according to claim 1 wherein scale markings of said first incremental pattern are in a first scale track and said at least one scale marking of said second incremental pattern is in said second scale track.
3. Scale reading apparatus according to claim 2 wherein said at least one scale marking of said second incremental pattern is also provided in a third scale track.
4. Scale reading apparatus according to claim 3 wherein the arrangement of the scale markings in said second and third scale tracks and their associated detecting means are such that the output signals from said detecting means are in quadrature.
5. Scale reading apparatus according to claim 1 wherein the scale markings of said first incremental pattern and the at least one scale marking of said second incremental pattern are located in the same scale track.
6. Scale reading apparatus according to claim 1 wherein the scale is a rotary scale.
7. Scale reading apparatus according claim 6 wherein the at least one scale marking of the second incremental pattern comprises one scale marking resulting in one marking per revolution.
8. Scale reading apparatus according to claim 1 wherein the first pitch is smaller than the second pitch.
9. Scale reading apparatus according to claim 8 further including a comparator to compare the speed of relative motion between the scale and readhead or a property of the system related to said speed to a threshold and thereby select the output from one of the first and second detecting means appropriate to said speed.
10. Scale reading apparatus according to claim 8 wherein the comparator compares the speed of relative motion between the scale and readhead to a threshold and wherein if the speed is above the threshold, the output from the second detecting means is used.
11. Scale reading apparatus according to claim 10 wherein the comparator compares the speed of relative motion between the scale and readhead to a threshold and wherein if the speed is below the threshold, the output from the first detecting means is used.
12. Scale reading apparatus according to claim 1, the scale including at least one reference mark.
13. Scale reading apparatus according to claim 12 wherein the at least one reference mark comprises a scale marking in said second pattern.
14. A method for detecting the relative position or speed of a scale and readhead of a scale reading apparatus comprising a scale, said scale having scale markings arranged in a first incremental pattern having a first scale pitch and at least one scale marking arranged in a second incremental pattern having a second scale pitch, said first scale pitch being different to said second scale pitch, and a readhead comprising first detecting means to detect said first incremental scale pattern and second detecting means to detect said second incremental pattern, the method comprising the steps of:
outputting signals from the first and second detector means.
15. A method according to claim 14 wherein the method includes the step of outputting a signal which indicates the validity of the first and second signals.
16. A method according to claim 14 wherein the method includes the step of comparing the speed of relative motion between the scale and readhead or a property of the system related to said speed to a threshold and thereby selecting the output from one of the first and second detecting means appropriate to said speed.
17. A method according to claim 16 wherein if the relative speed of the scale and readhead is above said threshold, the output from the second detecting means is used.
18. A method according to claim 16 wherein if the relative speed of the scale and readhead is below said threshold, the output from the first detecting means is used.
19. A method according to claim 14 wherein the first pitch is less than the second pitch.
20. A method according to claim 14 wherein a reference mark is provided and the method includes the step of using the reference mark to identify the position of the readhead with respect to the scale before returning to the output of the first detector from the output of the second detector.
21. A scale reading system comprising a scale and readhead moveable relative to each other;
and a communications link outputting data from the readhead;
wherein data of two different resolution levels is sent down the same communications link.
22. A scale reading system according to claim 21 wherein the data is sent down the communication link as a words comprising series of data bits.
23. A scale reading system according to claim 22 wherein one or more bits indicate the resolution level of a word.
24. A scale reading system according to claim 21 wherein at high resolution, a first portion of the data bits in the word are valid.
25. A scale reading system according to claim 24 wherein the first portion comprises all the data bits.
26. A scale reading system according to claim 21 wherein at low resolution, a second portion of the data bits in the word are valid.
27. A scale reading system according to claim 21 wherein the data relates to the relative position of the scale and readhead.
28. A scale reading apparatus comprising:
at least one scale marking;
a readhead with a transducer system to detect the at least one scale marking and to produce signals relating to the at least one scale marking; and
configuring means, which selects a signal decoding method to produce an output from the signal relating to the chosen function of the scale
29. A scale reading apparatus according to claim 28 wherein the configuring means acts on the signal to produce an output relating to one of an incremental function or at least one alternative function.
30. A scale reading apparatus according to claim 29 wherein the at least one alternative function comprises a limit mark function.
31. A scale reading apparatus according to claim 29 wherein the at least one alternative function comprises a reference mark function.
32. A scale reading apparatus according to claim 29 wherein the at least one alternative function comprises an absolute scale function.
33. A scale reading apparatus according to claim 28 wherein the configuring means is located on the readhead.
34. A scale reading apparatus according to claim 33 wherein the configuring means comprises a switch or pins located on the readhead.
35. A scale reading apparatus according to claim 28 wherein the configuring means is located externally from the readhead.
36. A scale reading apparatus according to claim 35 wherein the configuring means is provided by software.
37. A scale reading apparatus according to claim 28 wherein the transducer system detects individual scale markings of the at least one scale marking.
38. A scale reading apparatus according to claim 28 wherein the scale is provided with a fine incremental scale pattern and the readhead is provided with a fine incremental transducer system to detect relative motion between the fine incremental scale pattern and the readhead.
39. A scale reading apparatus according to claim 38 wherein the at least one scale marking is arranged to form an incremental scale and the configuring means configured to produce an incremental output, wherein the pitch of said at least one scale marking is larger than the pitch of scale marks in the fine incremental scale track.
40. A scale reading apparatus according to claim 38 wherein when the apparatus includes a comparator to compare the speed of relative motion between the scale and readhead or a property of the system related to said speed to a threshold to a threshold and thereby select the output from one of the at least one scale marking transducer system and fine pitch incremental transducer appropriate to said speed.
41. A scale reading apparatus according to claim 41, wherein at least one reference mark is provided and wherein on returning to the output from the fine incremental transducer, a reference mark is used to verify the position of the scale relative of the readhead.