Stanley Electric Co., Ltd

Kazuhisa Iwasaki

Toru Tanabe

Shigeru Kimura

Hideki Kitamura

Takao Seto

Yasushi Senoo

Kazuhiko Sugimura

Yukio Ohmamyuda

Yukio Omamyuda

A warning apparatus for warning of possible rear-end collision of a given vehicle having the warning apparatus with another vehicle preceding the given vehicle includes: a computer; a distance sensor for measuring a vehicle-to-vehicle distance to the another preceding vehicle; and a velocity sensor for measuring the velocity of the given vehicle. The computer computes a relative velocity of the given and the another preceding vehicle from a differential of the vehicle-to-vehicle distance and then computes an anticipated rear-end collision time by dividing of the vehicle-to-vehicle distance by the relative velocity of the given vehicle. The computer corrects the anticipated rear-end collision time in response to an acceleration and the relative velocity. The computer produces a warning of signal and an alarm is provided in response to the corrected anticipated rear-end collision time. A method of warning of a possible rear-end collision comprises the step of: detecting a vehicle-to-vehicle distance between a given vehicle and the another vehicle preceding the given vehicle; detecting a velocity of the given vehicle; computing an anticipated rear-end collision time T.sub.a of the given vehicle with the another vehicle, with an equation: ##EQU1## and producing a warning in response to the computed anticipated rear-end collision time T.sub.a.

Apparatus and method of warning rear-end collision

An optical distance measuring apparatus operable in accordance with an optical intensity modulating process to optically measure a distance between a driver's vehicle and a vehicle running ahead of his vehicle includes a light emitting portion serving as a light source to emit a distance measuring light beam, an optical lens system, a light receiving portion for receiving a reflected light reflected from the vehicle running ahead of the driver's vehicle through the optical lens system, and a processing system for correcting phase delay between the distance measuring light beam and the reflected light beam utilizing reference light beams emitted from a plurality of reference light sources to determine the distance. A processing system for determining the distance based on a time difference between the time when the distance measuring light beam is emitted from the light emitting portion and the time when the reflected light beam is received by the light receiving portion may be substituted for the processing system for the correcting phase delay between the distance measuring light beam and the reflected light beam. In addition, the system includes an apparatus for mounting on a vehicle body optical distance measuring apparatuses, each operable as a light emitting/receiving portion.

Optical distance measuring apparatus

A light-wave distance measuring apparatus has an intermittent controller for continuously changing periods of time during which a light intensity modulator 1 transmits and interrupts transmitting a light intensity modulated signal so as to avoid a synchronization of the light intensity modulated signal of the a first tranmitting apparatus with a light intensity modulated signal transmitted from a second light-wave distance measuring apparatus. The operation of the intermittent controller prevents a misfunction of the apparatus. Provisions of a self-speed detector, a time marker and a light transmission interval measuring circuit enables the apparatus to detect the speed of a target object. Thus, the apparatus is suitable for mounting on a vehicle. The apparatus operates accurately even when both the vehicle and the target object are moving. The apparatus also accurately operates without interference even when other similar light-wave distance measuring apparatus for vehicles are used in a small area.

Light-wave distance measuring apparatus for vehicle

A vehicular optical radar apparatus comprising a light emitting portion for irradiating a signal light on an object ahead and a light receiving portion for receiving a reflected light from the object. At least one of a light emitting lens and a light receiving lens are deformation-worked so that a distance between optical centers of the light emitting and receiving portions can be moved closer together, and an angle formed between an incident axis of incoming light and so that an outgoing light becomes small.

Vehicular optical-radar apparatus

A light source is constituted by a plurality of light emitting units which are arranged opposite to a light irradiating lens such that light emission from a part of the light source is changed to light emission from the whole surface of the light source and vice versa. In addition, a light irradiating apparatus having a light emitting diode used therefor as a light source comprises optical fiber(s) arranged between the light emitting diode and a light emitting lens such that a light emitted from the light emitting diode can be conducted to the light irradiating lens is disclosed. One end of each optical fiber is located at the position in the vicinity of the light emitting diode and other end of the same is located at the position substantially coincident with the focus of the light irradiating lens. In another embodiment, an optical fiber employable for an optical radar system has an outlet end of the optical fiber which is formed by two inclined surfaces in a wedge-shaped configuration. An inlet end of the optical fiber is formed at a right angle relative to an optical axis of the optical fiber.

Light irradiating apparatus having light emitting diode used as light

To measure a distance between two running vehicles a measurement signal is first generated by irradiating a light beam toward an article to be measured and then receiving the reflected light beam from the article. A reference signal and the measurement signal generated in the above way are input to a digital mix-down circuit which comprises two-stage flip-flop circuit to determine a phase difference between the reference signal and the measurement signal. The apparatus includes a clock delay circuit for delaying the high-going (rising) edge of the measurement signal while the reference signal is going high at an output terminal of a flip-flop circuit on the input side of the digital mix-down circuit, and a data delay circuit for delaying the down-going (falling) edge of the reference signal input into a data terminal of the flip-flop circuit. Usually, the clock delay circuit is electrically connected to the digital mix-down circuit via the data delay circuit, while the data delay circuit is electrically connected directly to the digital mix-down circuit. Alternatively, both the clock delay circuit and the data delay circuit may be electrically connected directly to the digital mix-down circuit.

Apparatus for measuring a distance between two running vehicles using

A two-eyed type optical distance measuring apparatus operable in accordance with a phase difference detecting process to optically measure a distance between the apparatus and an object to be measured is disclosed. To determine the distance between the apparatus and the object to be measured, a phase difference between the phase of a reflected light beam reflected from the object to be measured and the optical phase of a reference light beam derived from partial division of a distance measuring light beam emitted from a light source is detected and calculated. The apparatus includes as essential components a light source disposed in a housing on the light emitting side to emit a modulated distance measuring light beam therefrom toward the object to be measured, a light receiving element positioned in a housing on the light receiving side and a reference light introducing mechanism for introducing a part of the modulated distance measuring light beam emitted from the light source into the light receiving element via an optical fiber. To prepare the reference light beam, a shade is arranged at the intermediate part of the housing on the light emitting side. In addition, an iris mechanism is disposed on the incident side of the optical fiber to variably adjust an optical quantity of the reference light beam.

An optical distance measuring apparatus operable in accordance with a phase difference detecting process, comprises a processing system including a central processing unit and first and second local oscillating circuits which serve to detect and calculate a phase difference between the electrical phase of a modulated signal outputted from a reference oscillator electrically connected to a light source via a modulating circuit and the electrical phase of a demodulated signal outputted from a demodulating circuit electrically connected to a light receiving portion so as to determine a distance between the apparatus and an object to be measured based on the detected phase difference with reference to the electrical phase of a reference signal outputted from the reference oscillator. A first local oscillating signal is outputted from the first local oscillating circuit and it is then subjected to frequency conversion together with the demodulated signal in a mixer so as to output a first intermediate frequency, while a second local oscillating signal is outputted from the second local oscillating circuit and it is then subjected to frequency conversion in a mixer together with the demodulated signal so as to output a second intermediate frequency signal. One of the first and second intermediate frequency signals is selected depending on the present distance between the apparatus and the object to be measured.

An optical distance measuring apparatus is disclosed which is operable in accordance with a phase difference detecting process wherein a processing system including a central processing unit and a digital type mix-down circuit detects and calculates a phase difference between the electrical phase of a signal output from a light receiving portion in response to receipt of a reflected light beam and the electrical phase of a reference signal output from a reference oscillator so as to determine a distance between the apparatus and a object spaced at a distance to be measured with reference to the electrical phase of a local oscillation signal output from a local oscillator. A second circuit system of the processing system on the light receiving side includes a ladder resistance type attenuation circuit, a multiplexer, an veriable gain current amplifier, a wave shape correcting circuit and a signal amplitude detecting circuit. When the signal amplitude detecting circuit detects that the signal derived from the reflected light beam has an amplitude in excess of a predetermined value, the central processing unit controls the multiplexer so as to reduce a magnitude of the amplitude. In addition, an optical distance measuring apparatus operable in accordance with a time difference detecting process is disclosed.

Growing community of inventors

Yokohama, Japan

Kazuhisa Iwasaki