Ultrasonic distance detector

• US 4,490,716 A
• Filed: 11/13/1981
• Issued: 12/25/1984
• Est. Priority Date: 11/14/1980
• Status: Expired due to Term

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Ohtsuka, Mitsugi, Maeno, Tsuyoshi, Tsuda, Tadashi, Hiramatsu, Seiichirou
• Primary Examiner(s): Groody, James J.
• Application Number:
  US06/321,224
• Time in Patent Office: 1,138 Days
• Field of Search: 340/32-34, 340/52 H, 340/904, 340/902, 340/901, 367/108, 367/909, 367/107
• US Class Current: 340/904
• CPC Class Codes: G01S 15/04 Systems determining presence of a target
• CPC Class Codes: G01S 15/42 Simultaneous measurement of distance and other co-ordinates indirect measurement G01S15/46
• CPC Class Codes: G01S 15/87 Combinations of sonar systems
• CPC Class Codes: G01S 15/931 of land vehicles
• CPC Class Codes: G01S 7/56 Display arrangements short-range imaging G01S7/52053
• CPC Class Codes: Y10S 367/909 Collision avoidance

Abstract

An ultrasonic detector for roadway vehicles comprises an array of electroacoustic transducers mounted on the rear of the vehicle. The transducers are sequentially driven by a transmitter circuit to transmit a pulsed, laterally shifting ultrasonic energy toward an object located behind the vehicle in one of plural regions defined by partially overlapped directivity patterns of adjacent transducers. A receiver circuit is coupled to the transducer array to receive echos returning from the object during the interval between successive beam transmissions. A logic circuit detects the lateral position of and the distance to the object for giving relevant indications on a display unit, the audible tone being variable depending on object distance. An audible warning device is optional.

Claims

1. An ultrasonic alarm system for detecting at least one object located with respect to a moving vehicle, comprising:

a first array of ultrasonic transmitting transducers for emitting ultrasonic energies in respective directivity patterns;

a second array of ultrasonic receiving transducers disposed alternatively with said ultrasonic transmitting transducers and actuatable in timed alternate relation to said ultrasonic transmitting transducers for receiving ultrasonic echoes reflected from any objects located in laterally overlapping detecting regions defined in said directivity patterns;

first means for sequentially energizing said ultrasonic transmitting transducers to emit the ultrasonic energies successively in said directivity patterns;

second means for sequentially receiving echo signals indicative of said ultrasonic echoes from said ultrasonic receiving transducers;

third means for generating first signals representative of sequential operations of said ultrasonic transmitting transducers;

fourth means for generating second signals of varying durations indicative of different distance ranges in each of said laterally overlapping detecting regions;

display means comprising a matrix of light-emitting elements; and

display control means responsive to said echo signals and said first signals for energizing rows of said light-emitting elements to indicate any objects in said laterally overlapping detecting regions and responsive to said echo signals and said second signals for energizing columns of said light-emitting elements to indicate any objects in said distance ranges, said display control means comprising;

a plurality of AND gates each having first input terminals receptive of said echo signals, second input terminals receptive of said first signals, and an output terminal for issuing position signals, and a plurality of groups of D-type flip-flops, said D-type flip-flops in each group having input terminals receptive of said second signals, respectively, clock terminals receptive of one of said first signals, and output terminals for issuing energization signals to one of said columns of said light-emitting elements.

2. An ultrasonic alarm system according to claim 1, including an audible alarm generator responsive to said energization signals for generating an audible warning having a variable tone dependent on the position of the objects in said distance ranges.

3. An ultrasonic distance detector for detecting an object moving with respect thereto, comprising:

first and second ultrasonic transmitting transducers arranged in a laterally spaced apart relationship for transmitting ultrasonic energies of identical directivity pattern from each transmitting transducer;

an ultrasonic receiving transducer located between said transmitting transducers and having a directivity pattern which partially overlaps the directivity patterns of said transmitting transducers to define laterally spaced apart first and second object detecting regions for receiving an ultrasonic echo returning from an object located therein;

a transmitter circuit for sequentially activating said first and second transmitting transducers with a burst of ultrasonic pulses to transmit pulsed ultrasonic energy from each transmitting transducer and laterally shift the point of transmission to the other transmitting transducer;

a receiver circuit, coupled to said receiving transducer, for allowing it to receive said echo during an interval between successive energy transmissions from said first and second transmitting transducers;

actuation signal generator means for generating an actuation signal indicative of energization of one of said first and second ultrasonic transmitting transducers as sequentially activated by said transmitter circuit;

display means including a first display area for displaying a distance up to an object in said first object detecting region and a second display area for displaying a distance up to an object in said second object detecting region, said display means including a plurality of light-emitting elements arranged in a two-dimensional pattern of horizontal rows indicative of positions of the objects in said first and second object detecting regions and vertical columns comprising said first and second display areas, respectively, for representing the distances to the objects in said first and second object detecting regions; and

display control means for deriving the distance to the object from a time interval which runs from the time when the ultrasonic energy is transmitted from one of said first and second ultrasonic transmitting transducers by said transmitter circuit to the time when the ultrasonic echo is received by said receiver circuit, and for effecting a display of the derived distance on one of said first and second display area which corresponds to said actuation signal from said actuation signal generator means;

said ultrasonic distance detector including reference signal generator means for generating first and second reference signals representative of first and second distance ranges, respectively, in the direction of emission of the ultrasonic energies in timed relation to the emission of the ultrasonic energies from said first and second ultrasonic transmitting transducers, said display control means including means for comparing a signal from said receiver circuit indicative of reception of the ultrasonic echo with said first and second reference signals from said reference signal generator means to determine whether the object is located in said first or second distance range, and means for energizing those light-emitting elements which correspond to the determined distance range, if any, and to the object detecting region indicated by the actuation signal generator means; and

said ultrasonic distance detector including means for varying the reference signal corresponding to the determined distance range, if any, in order to increase the determined distance range and for restoring said reference signal representative of the original distance range when no object is detected in said distance range.