EP0421437A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Scanning tunneling microscope having proper servo control function
Assignee: Olympus Corp
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Filing: 1990-10-04
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Granted: —
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Expires: 2010-10-04
Abstract
Abstract A scanning tunneling microscope includes a piezoelectric driver (15) expanding and contracting according to a voltage applied thereto to adjust the distance between a sample (17) and a probe (16). A servo circuit outputs a servo voltage (19) to control the expansion and contraction of the piezoelectric driver (15) to keep a tunnel current flowing between the sample (17) and the probe (16) at a constant value. A correction voltage generating circuit (31) generates a given correction voltage to correct a voltage to be applied to the piezoelectric driver (15). An adding circuit (33) adds the servo voltage and the correction voltage together and supplies an added output to the piezoelectric driver (15). A control circuit (1) controls the correction voltage according to the servo voltage to set the added output to a given reference voltage.
Inventors
- 👤 Hirofumi Miyamoto
- 👤 Takao Okada
- 👤 Tsugiko Takase
- 👤 Shuzo Mishima
- 👤 Hiroko Ota
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 12:35
CPC Classifications
G; G01; G01Q; G01Q60/00; G01Q60/10; G01Q60/16; B; B82; B82Y; B82Y35/00; Y; Y10; Y10S; Y10S977/00; Y10S977/84; Y10S977/849; Y10S977/85; Y10S977/851
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
189 words
A scanning tunneling microscope characterized by comprising: a piezoelectric driver (15) capable of expanding and contracting to adjust a distance between a probe (16) and a sample (17) according to a voltage applied thereto, the distance including a distance at which a tunnel current can flow between said probe (16) and said sample (17); a servo circuit (19) for outputting a servo voltage for controlling expansion and contraction of said piezoelectric driver (15) to keep the tunnel current at a constant value; correction voltage generating means (31) for generating a given correction voltage to correct a voltage to be applied to said piezoelectric driver (15); adding means (33) for adding the servo voltage output from said servo circuit (19) and the correction voltage supplied from said correction voltage generating means (31) to each other to supply an added output to said piezoelectric driver (15); and control means (1) for controlling the correction voltage supplied from said correction voltage generating means (31) based on the servo voltage output from said servo circuit (19) so as to keep the added output from said adding means (33) at a given reference voltage.
Claim 2
Dependent Claim
189 words
A scanning tunneling microscope characterized by comprising: a piezoelectric driver (15) capable of expanding and contracting to adjust a distance between a probe (16) and a sample (17) according to a voltage applied thereto, the distance including a distance at which a tunnel current can flow between said probe (16) and said sample (17); a servo circuit (19) for outputting a servo voltage for controlling expansion and contraction of said piezoelectric driver (15) to keep the tunnel current at a constant value; correction voltage generating means (31) for generating a given correction voltage to correct a voltage to be applied to said piezoelectric driver (15); adding means (33) for adding the servo voltage output from said servo circuit (19) and the correction voltage supplied from said correction voltage generating means (31) to each other to supply an added output to said piezoelectric driver (15); and control means (1) for controlling the correction voltage supplied from said correction voltage generating means (31) based on the servo voltage output from said servo circuit (19) so as to keep the added output from said adding means (33) at a given reference voltage.
Claim 3
Dependent Claim
47 words
The microscope according to claim 1, further comprising an approach detection/instantaneous contraction circuit (32) for selecting one of the added output and a maximum contraction voltage for setting said piezoelectric driver (15) into the maximum contracted state and outputting the selected voltage to said piezoelectric driver (15).
Claim 4
Dependent Claim
55 words
The microscope according to claim 2, characterized in that said approach detection/instantaneous contraction circuit (32) includes a switching circuit (132) for selecting one of the added output and the maximum contraction voltage, and a flip-flop circuit (133) for setting said switching circuit (132) to the maximum contraction selecting position when a tunnel current is detected.
Claim 5
Dependent Claim
73 words
The microscope according to claim 1, further comprising an A/D converting section (7) having an A/D converter (7a) for converting said servo voltage to digital data and supplying the digital data to said control means (1) and a real time line memory (7b) for storing the digital data; and a monitor TV (34) for reading out the digital data from said memory (7b) and displaying the digital data on a real time basis.
Claim 6
Dependent Claim
32 words
The microscope according to claim 4, characterized in that said A/D converting section (7) further includes a variable amplifier circuit (7c) for variably amplifying said servo voltage from said servo circuit (19).
Claim 7
Dependent Claim
58 words
The microscope according to claim 5, characterized in that said variable amplifier circuit (7c) includes an analog multiplexer (71) for outputting a voltage signal corresponding to the selected signal from said control means (1) in response to said servo voltage and an inverting type amplifier (72) for inverting and amplifying the voltage signal from said analog multiplexer (71).
Claim 8
Dependent Claim
57 words
The microscope according to claim 1, characterized in that said control circuit (1) includes a modulation pattern generating circuit (1b) for generating modulation pattern data for finely modulating the distance between said probe (16) and said sample (17), and the correction signal from said correction signal generating means (31) is controlled according to the modulation pattern data.
Claim 9
Dependent Claim
34 words
The microscope according to claim 1, characterized in that said correction voltage generating means (31) includes a D/A converter (31) for converting digital data from said control means (1) to an analog correction voltage.
Claim 10
Dependent Claim
29 words
The microscope according to claim 2, further comprising a high voltage amplifier circuit (20) for amplifying an output from said approach detection/instantaneous contraction circuit (32) to a high voltage.
Claim 11
Dependent Claim
120 words
The microscope according to claim 1, further comprising a scanning circuit (5) for scanning said probe (16) along said sample (17), said scanning circuit (5) including means (51, 52, 53, 54) for causing said probe (16) to scan at least a first scanning range corresponding to a portion of said sample (17) to be observed and a second scanning range including the first scanning range and setting the size of said first scanning range; and adding means (55, 56) for adding output data from said setting means (51, 52, 53, 54) and data relating to a reference position of said first scanning range, corresponding to a reference position of said second scanning range, to each other in a digital manner.
Claim 12
Dependent Claim
73 words
The microscope according to claim 10, characterized in that said setting means includes a counter circuit (51) for effecting the count up/down operation according to a scanning starting signal from said control means (1) and a bit shift circuit (52) for shifting an output from said counter circuit (51) by a desired number of bits to the least significant bit side according to scanning range setting data supplied from said control means (1).
Claim 13
Dependent Claim
113 words
The microscope according to claim 11, characterized in that said scanning circuit (5) includes an upper digit side latch circuit (53a) for holding high-order bits of said reference data and a lower digit side latch circuit (53b) for holding low-order bits thereof, and said adding means (55) includes an upper digit side adder (55a) for adding high-order bits output from said upper digit side latch circuit (53a) and high-order bits output from said bit shift circuit (52a) to each other, and a lower digit side adder for adding (55b) low-order bits output from said lower digit side latch circuit (53b) and low-order bits output from said bit shift circuit (52a) to each other.
References Cited (Backward Citations)
No citation records indexed.
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