Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.