A second light transmit portion of a phase shift mask is formed of a molybdenum silicide nitride oxide, or a molybdenum silicide oxide, or a chromium nitride oxide, or a chromium oxide, or a chromium carbide nitride oxide film converting a phase of transmitted exposure light by 180° and having the transmittance of at least 2% and less than 5%. In the manufacturing method of the second light transmit portion, a molybdenum silicide nitride oxide film, or a molybdenum silicide oxide film, or a chromium nitride oxide film, or a chromium oxide film, or a carbide nitride oxide film is formed by a sputtering method. Consequently, with a conventional sputtering apparatus, the second light transmit portion can be formed, and additionally, etching process of the phase shifter portion is required only once, so that probabilities of defects and errors in the manufacturing process can be decreased.

Phase shift mask and manufacturing method thereof and exposure method using phase shift mask

Double-channel single-frequency laser interferometer

Disclosed is a distance measuring apparatus which includes: a first pulse generating means (135) which generates reference signals; a second pulse generating means (137) which generates subject detection signals; a time measuring section (139) which measures a period of time from a time when a first pulse is generated to a time when a second pulse is generated; a first phase detecting section (141) which detects the first phase of a signal received using a signal at a first frequency; a second phase detecting section (163) which detects the second phase of a signal received using a signal at a second frequency; and a distance calculating section (165) which calculates the distance to the subject on the basis of output from the time measuring section, the first phase detecting section and the second phase detecting section.

Distance measuring apparatus and distance measuring method

In a radar of FM-CW system having a transmitting and a receiving unit 20 and 28 both connected to a transmitting/receiving antenna 26 via a circulator 24, a high frequency switch 22 for transmission, is inserted and turns on and off the path between the transmitting unit 20 and the circulator 24, and in the receiving operation of the receiving unit 28 the high frequency switch 22 for transmission is controlled according to a switch control signal 320a provided from a signal processing unit 30 such as to be held "off" to hold the transmission output of the transmitting unit 20 "off" for a predetermined time, thus reducing sneak noise component between the transmission and reception. Thus it makes possible to reduce sneak noise between the transmission and reception, and readily realize cost reduction without need of separate antennas for the transmission and reception.

Radar of FM-CW system

The invention discloses an orthogonal homodyne laser interferometer and a measurement method thereof. The interferometer is simple and reliable in structure, and comprises a helium-neon laser, a beam splitter prism, a lambda/8 wave plate, a cubic pyramid prism, a measuring cubic pyramid prism, a precision guide rail, a photoelectric detector, a small signal amplification module, a band-pass filter module, an analog-to-digital conversion unit and a computer data processing unit. According to the invention, laser light emitting by the laser is split into reference light and measuring light after passing through the beam splitter prism, the measuring light firstly passes through the lambda/8 wave plate and is then reflected by the measuring cubic pyramid prism so as to acquire a light beam, the light beam passes through the lambda/8 wave plate again and generates interference with a reference light beam reflected by a reference cubic pyramid prism, and finally, two paths of orthogonal polarized light are acquired after passing through a polarization splitting prism; the photoelectric detector receives light signals and converts the light signals into electric signals, and signal conditioning is carried out by an amplification and filtering module; and the analog-to-digital conversion unit is controlled by a computer unit to acquire the conditioned electric signals, the phase is demodulated, and the real-time displacement of the measuring cubic pyramid prism is acquired and displayed.

Orthogonal homodyne laser interferometer and measurement method thereof

PURPOSE:To make it possible to measure a distance with high accuracy, by detecting the phases of beat signals at two points of time different in frequency and further obtaining an extend displacement signal. CONSTITUTION:The beat signal SB obtained in a microwave circuit 1 is amplified by an amplifying circuit 4 to be inputted to phase detection circuits 5, 6 and a distance operation circuit 9 and, at the time t1 when the frequency of a transmission microwave comes to f1, a phase detection order signal SD1 is inputted to the circuit 5 from a modulation circuit 3 and the phase theta1 of the signal SB at this time is outputted from the circuit 5 and a displace amount x3 is measured by a displacement measuring circuit 8. Next, at the time t2 when the frequency of the transmission microwave is increased to come to f2, a phase detection order signal SD2 is outputted to the circuit 6 from the circuit 3 and the phase theta2 of the signal SB at this time is outputted from the circuit 6. Further, extend displacement amount x2 is calculated from the phases theta1, theta2 by an extend displacement amount detection circuit 7. A coarse definite distance RT is calculated from the signal SB by the circuit 9 and, further, a fundamental distance x1 is calculated from the distance RT and the wavelength of the displacement amount x2 by a fundamental distance operation circuit 10. The distance x1 and the displacement amounts x2, x3 are added by an adder 11 to be outputted from an output circuit 12 as output X.

Microwave range finder

PURPOSE:To enable the measurement of the displacement of a rotating shaft affected little by noise by an inexpensive construction wherein a single frequency laser is used, a wave plate and others are provided on the opposite end faces of the rotating shaft, two AC signals having informations on the displacement are taken out, and a phase difference between them is determined. CONSTITUTION:A light of a single frequency emitted from a laser 1 is split onto the right and left sides by a beam splitter 2. The light on the left side is split in two by a beam splitter 3, and a reflected light reaches a photodetector 10 as a reference light. A transmitted light passes, as a measured light, through a rotary 1/4 wave plate 6 fitted to the left end of the rotating shaft of a motor 23, is reflected by a mirror 7 and deflected at an angle of 90 deg. in the direction by a beam splitter 4, and reaches the detector 10. Herein a sine wave signal obtained by the addition of the reference light and the measured light is detected. The light on the right side is subjected to the same operations as the above in similar devices provided at the right end of the rotating shaft, and a sine wave signal is detected in a photodetector 20. The two sine wave signals are sent to a phase difference detector circuit 20 and a phase difference between them is detected therein. The signal obtained from the detection is sent to a displacement operation circuit 22, and an amount of the displacement in the axial direction of the rotating shaft is thereby calculated.

Optical displacement measuring apparatus

PURPOSE:To correct the error generated by the variation in a wavelength caused by the change of the temp. in a light path, by catching the effect due to temp. as the change in the length of an optical fiber and using the same as a correction factor. CONSTITUTION:The expansion and contraction quantity of the optical fiber 9 arranged in the vicinity of the light path between an interferometer 3 and a reflecting mirror 4 is optically measured by an interferometer 8 and a receiver 10 and outputted as an electric signal by a fiber length operation circuit 11. On the basis of this signal, the average temp. distribution in this light path is calculated by an average temp. operation circuit 12 and the measured length value between the interferometer 3 and the reflecting mirror 4 is corrected on the basis of the output from said operation circuit 12 by a displacement quantity correction circuit 13. At this time, since the optical fiber 9 expands and contracts in proportion to temp. and a thermal time constant is small, by calculating the measured length value between the interferometer 3 and the reflecting mirror 4, the temp. distribution of the light path is calculated. On the basis of the temp. distribution thus obtained, the correction of the measured length value is performed to make it possible to perform highly accurate measurement.

Length measuring device by laser beam

PURPOSE:To attempt improvement of torque detecting accuracy, by bringing two laser-beams into interference using 2-frequency laser beams and detecting a twist angle of a torsion bar (torsion spring) by measuring a phase difference of its beat signal. CONSTITUTION:A polarizer (linear light polarizer) 9 is arranged through an angle of 45 deg. relative to perpendicularly intersecting both beams (2-frequency components) the optical axis of which passed a 1/2-wave-length plate 8 and each 45 deg. component is taken out for interference and photo-detectors 10, 11 make photo-electric conversion of both beams after their passage through the polarizer 9. A beam 1 follows a route: 1/2 wave-length-plate 7 polarizer 9 photo-detector 10 and a beam 2: 1/2 wave-length plate 9 photo-detector 11, and a photo-detector output after the photoelectric conversion, is input to an phase identifying apparatus 12. The apparatus 12 identifies a phase difference of both photo-detector outputs and a torque arithmetic operator 13 calculates a torque from the phase difference.

Optical torque detector

PURPOSE:To perform highly accurate measurement in a wide measuring range, by employing an output system due to a Doppler method or phase difference method corresponding to the moving speed of an article to be measured. CONSTITUTION:The orthogonal two-frequency laser beams (l) emitted from a laser head 1 is split by a beam splitter 2 and one of them is photoelectrically converted by a photoelectric converter 5 to become a beat signal V while the other one is photoelectrically converted by a photoelectric converter 6 as a beat signal V' to which a Doppler signal is superposed between an interferometer 3 and a reflecting mirror 4 being an article to be measured. The signals V, V' are inputted to a displacement operation circuit 7a, a phase detection circuit 8 and a speed detection circuit 11. The speed signal VS from the circuit 11 is compared with a speed threshold value V0 by a speed judge circuit 13. The circuit 13 supplies a signal H to an output selection circuit 12 at the time of VS>V0 and supplies a signal L to said circuit 12 at the time of VS<V0. The circuit 12 selects whether either one of the output of the circuit 7a due to the signal H (the measured value due to a Doppler method) and the output of the displacement operation circuit 7c due to the signal L (the value obtained by adding the output of the circuit 7a and the measured value being the output of the circuit 8 due to a phase difference method) is set to a final output.

Murakami Satoshi

Papers

Microwave range finder

Optical displacement measuring apparatus

Length measuring device by laser beam

Optical torque detector

Length measuring apparatus by laser beam