JPS595979A - Apparatus for displaying rear obstacle for vehicle - Google Patents

Abstract

PURPOSE:To make back running in a narrow place extremely safe, by providing function wherein the min value among distances to an obstacle detected by plural wave receiving means is displayed and the mostly approaching detecting means is selectively displayed. CONSTITUTION:The titled apparatus is constituted from fource ultrasonic wave transmitter receivers 11-14 having charge of the monitoring of the rear specific region of a vehicle and a display instrument 2 provided in the vehicle. The display instrument 2 is provided with a selection circuit 22 selecting the transmitter receivers 11-14, a transmission and reception circuit 23 exciting the selected transmitter receivers 11-14 to generate ultrasonic waves and treating the receiving signal due to reflected waves, a detection circuit 24 for detecting time difference from the transmission of ultrasonic waves to the reception thereof, a memory circuit 26 for storing the transmitter receivers 11-14 wherein a distance obtained by converting the detected time reference to a distance is min. and storing said distance, a display circuit 27 including a display lamp displaying the distance stored by the memory circuit and the transmitter receivers 11- 14 at the time when the selection of the transmitter receivers 11-14 takes round and a control circuit 21 controlling the operation timing of each circuit. When the vehicle is retracted, a driver can accurately know a distance to an obstacle by the display device in the vehicle.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a rear obstacle display device for a vehicle that detects and displays the distance to an obstacle behind the vehicle. This invention relates to an ultrasonic obstacle display device that allows distance to be determined.

This type of device has an ultrasonic transducer mounted on the rear bumper of the vehicle, and a display instrument that converts the ultrasonic reflection time into distance and displays it in a position within the vehicle where the driver can see it when backing up. . Conventional display instruments either turn on a lamp when the distance to an obstacle is less than a set value, or turn on a pergraph depending on the distance to the obstacle.
It was not possible to accurately determine the distance to an obstacle. There are also devices that use multiple transducers to improve reliability, but they do not have a function to select and display the transducer that is closest to the obstacle, so the vehicle approaches the obstacle in an inclined direction. In this case, it was unclear which part of the rear of the vehicle was closest to the obstacle.

In order to solve the above-mentioned problems, the present invention has been developed for use in vehicles, which has a function of digitally displaying the minimum distance to an obstacle detected by a plurality of wave receiving means, and selectively displaying the closest wave receiving means. The present invention attempts to provide a rear obstacle display device.

The present invention will be explained below with reference to the illustrated embodiments.

As shown in FIG. 1, the obstacle display device according to the present invention includes four ultrasonic transducers 11, 12, .
13, 14, and a display instrument 2 installed inside the vehicle. The display instrument 2 includes a selection circuit 22 that selects the four transducers 11 to 14, and a receiver that excites the selected transducer 11 to 14 to generate ultrasonic waves and processes the received signal by reflected waves. A circuit 23, a detection circuit 24 that detects the time difference between transmission and reception of ultrasonic waves, a conversion circuit 25 that converts the detected time difference into distance, and stores the transducers 11 to 14 with the minimum converted distance and their distances. When the selection of the four transducers 11 to 14 has been completed, the distance stored in the memory circuit and the transducer 1
It is equipped with a control circuit 21 that controls the display movement timing for displaying numbers 1 to 14.

The control circuit 2] consists of a reference clock generation circuit 211 and a control signal generation circuit 212, as shown in FIG. The reference clock generation circuit 211 generates a clock signal 211a for operating the control signal generation circuit 212 and a clock signal 211b for distance measurement. clock signal 211
a is a square wave pulse with a period of a m5ec (see FIG. 4), and based on this clock signal 211a, the control signal generation circuit 212 generates control signals 212a and C0, which will be described later.
Generates NT. Furthermore, the period of the upper rudder 60m5ec is the time during which the distance to the obstacle is calculated and stored for the selected transducers 11 to 141, and therefore the transmission and reception of the four transducers 11 to 14 has a period of 240m8eo. It will be held in

In FIG. 2, the selection circuit 22 consists of four selection switches 221% 222, 223, and 224 that selectively connect the transducers 11 to 14 to the next stage transceiver circuit 23.
In response to the control signal 212a issued from the control signal generation circuit 1 212, the selection switches 221 are sequentially closed.

The transmitting/receiving circuit 23 includes a transmitting/receiving switch 231, a transmitting pulse generator 232, a transmitting/receiving switching circuit 233, an amplifier circuit 234,
Bandpass filter 235, detector 236, comparator 23
Consists of 7. The transmission/reception changeover switch 231 receives the control signal 2.
Output signal 233 of the transmission/reception switching circuit 233 synchronized with 12a
a, the transmitting side and the receiving side are selectively closed. When the transmitting side is closed, the output bus from the transmission bus generator 232 is sent to the transducers 11 to 14 selected by the selection circuit 22, and ultrasonic waves are transmitted. If the receiving side is still closed, the transducer 11~
The echo signal of the reflected wave detected in 14 is transmitted to the amplifier circuit 234.
sent to.

The time difference detection circuit 24 is a circuit that receives a signal 232a synchronized with the transmission circuit of the transmission pulse generator 232 and outputs a signal 24a (see FIG. 4) that remains at "1" level until it receives an echo signal 237a due to a reflected wave. It is.

The conversion circuit 25 converts the AND gate 2 using the signal 24a.
51 is open, the distance measurement clock signal 211b
This circuit converts this clock signal 211b into a distance signal ST expressed by a 2-digit, 6-bit BCD code using a built-in counter, and outputs the signal. In this embodiment, the distance display range is 2.5 m, so 2.
In order to display up to 100IOIJ, which is a 5m BCD code, the signal generator ST requires 6 bits.

As shown in FIG. 3, the storage circuit 26 includes a transducer storage circuit 261 that stores the transducers 11 to 14 with the minimum distance, a distance storage circuit 262 that stores the minimum distance value, and a distance storage circuit 262 that stores the minimum distance value, and a distance storage circuit 262 that stores the minimum distance value. It consists of a value comparison circuit 263.

2611.2612.26 in the transducer storage circuit 261
13.2614.2615.2616 and 2617 are 1-bit data latches, and 261E is a 4-bit data latch, which stores the input signal of the D terminal at the timing of the pulse that enters the C terminal, and transfers it to the corresponding C terminal. This is what is output. Furthermore, the output of the C terminal is reset by a pulse input to the R terminal. The Q terminal outputs a complementary signal to the Q terminal output signal.

In the distance storage circuit 262, 2621 and 2622 are 6-bit data latches, which operate in the same way as the data latches described above.

2631.2632.263 in distance value comparison circuit 263
3.2634.2635.2636 are each 4-bit digital comparators, and in order to compare 6-bit distance values, comparator 2631 and comparator 2 are used.
632, comparator 2633 and comparator 2634
, comparator 2635. ! : Converters 2636 are connected in rows and used integrally. The comparators 2631 to 2636 compare the input of the A terminal and the input of the B terminal, and if the input of the A terminal is larger than the input of the B terminal, r A>B. If it is equal to [A=BJ terminal, and if the input of A terminal is smaller than the input of B terminal, [A<BJ terminal], a level "1" is output. Here, the A terminal of the comparator 2633.2634 has a BOD code [100101
J, and the comparator 2635.2636 (7) B terminal indicates 0.3m.
are set respectively. In addition, a signal that becomes "1" level when the gear position of the transmission is in forward motion is added to the input terminal G of the ORG) 263B.

The storage circuit 26 described above is operated by the control signal 0ONT output from the control signal generation circuit 212. The control signal 0ONT has seven types of control signals L0, Ll, Ll, B
8, B4, L, , R.

The display circuit 27 includes a seven segment light emitting diode numeric display 2721.2731, an EICD-seven segment display decoder 272.273, and a lamp 2711.
．． 2'F12.2'713.2714.2715, a lambto fiber 271, a piezoelectric buzzer 276, etc.

When a "1" level signal is applied to the B terminal of the decoder 272.273, the numeric display 2721.2731
goes out. 2 KH to terminal E of AND game 1275
A square wave of about z is input, and when this gate 275 is opened, the square wave is applied to a piezoelectric buzzer 276, causing the buzzer 276 to sound. Further, the input terminal F of the AND gate 274 is supplemented with the complementary signal of the terminal G of the above-mentioned OR gate 263B ("l" level /I/ at the time of retraction).

An exploded perspective view of the display instrument 20 equipped with the above circuit is shown in FIG. A in the figure is an aluminum decorative board, with a hole AI in the lower half and a lamp 2711.2 in the upper half.
712.2'F 13.2'714 is installed. B
is a transparent column acrylic board, C is a printed board, the letters ``Ato'' and rmJ are etched, and the letters ``5'' are etched.
TOP" is obtained by etching the periphery C1 of the rectangle, leaving the text portion intact. Further, C2 is a hole. D is a resin chassis, and lamps P%Q, 2 are placed in a concave portion D2 formed in a concave shape to serve as a reflector on the front plate D1.
715 is installed. Here, lamps P and Q are for spring μ illumination. Number display 2721.273 in hole D4
1 is fitted. In addition, there is a lamp 2711 on the top of the front plate D1.
-2714 is provided with a punch hole D3 through which it is inserted.

The circuit components constituting each of the circuits described above are mounted on a printed circuit board (not shown) and housed in the rear part of the chassis D.

Therefore, if the decorative board A is stacked on the front board D1 of the chassis D and the acrylic board B1 and the printed board C are inserted between them,
The distance of closest approach is displayed by indicators 2721 and 2731 through the hole C2 and the acrylic plate B, and the transducers 11 to 14 indicating the distance of closest approach are displayed by lamps 2711 to 2714. Also, when the lamp 2715 lights up, 1-5TO
The letters PJ are displayed through the acrylic board B.

The operation of the obstacle display device having the above configuration will be explained below based on FIG. 4.

The left half of the timing chart in this figure shows the case where the transducer 12 approaches the closest, and the right half shows the case where the transducers 12 and 14 approach the closest at the same distance.

In the first cycle T1 of the clock signal 211a,
When the selection switch 221 is closed by the control signal 212a and the transducer 11 is selected, the output signal 233a of the transmission/reception switching circuit 233 synchronized with the control signal 212a causes the transmission side 1 of the transmission/reception switching switch 231 to be closed. Output pulses are sent from the transmission pulse generator 232 to the transducer 11. After sending out the output cover/l/nu, press the sending/receiving switch 2.
3; L immediately switches to the receiving side. The received echo signal is amplified to an appropriate voltage level by an amplifier circuit 234, noise is removed by a bandpass filter 235, and then passed to a detector 23.
6, and when it reaches a constant value of 1v or more, the comparator 23'? It is output as a signal 23'7a.

The time difference detection circuit 24 receives a signal 232a synchronized with the start of transmission.
According to the arrival time difference between the echo signal 23'7a and the echo signal 23'7a,
'' level is output. The conversion circuit 25 that receives the signal 24a outputs a distance signal DIST of the ECD code proportional to the signal 24a. The distance direct signal DIST is input to the A terminal of the comparators 2631 and 2632, and compared with the distance signal input to the B terminal. The distance signal input to this B terminal was latched by the latch 2621 during the previous cycle.
This is the signal stored in the Q terminal and output from its Q terminal. When the distance signal at the A terminal is equal to or smaller than the distance signal at the B terminal, the latch 2632 outputs [A=Bj terminal, or "A<BJ terminal output reaches Ill level μ".
Therefore, the Lm signal becomes 11'' level. latch 2
The output of terminal Q of 611 becomes "L" level μ at the timing of control signal LL. This output signal is ANDG)26
1B and reaches the input terminal D1 of the latch 261E.

For the first psych/I/Tl of clock signal 211↓1a, the control signal Lo is output from the control signal generation circuit 212 regardless of the LE multiplied signal level μ, and at this timing, the distance signal generator ST is activated by the latch 2621. is memorized.

Similarly, ultrasonic waves are transmitted and received at the next psyche μTj after the clock signal 211a, and a signal 24a is obtained. Here, the duration of signal 2.4a is assumed to be 7. Since this time l is shorter than the duration of signal 24a at psych/L'Tt, the BCD converted distance signal ST is smaller than the distance signal ST stored in latch 2621 at psych iVT+. Therefore, comparator, rater 2
632 (7) [A<'The output of the BJ terminal is not at the "1" level, and the LE multiplied signal remains at the "1" level μ. In this state, the control signal is L! When input, the output of the terminal Q of the latch 2612 becomes "1" level. This output signal is AND
2610, input terminal D of 261E
Reach 2. At this time, the output of the terminal Q of the latch 2612 is "
0'' level, the game l-261B closes and the latch 264E closes.
The signal at the input terminal D1 becomes "0" level. Signal LE
is at the "1" level, the control signal Lo is output from the signal generating circuit 212, and at this timing, the distance signal ST during cycle/I/T2 is stored in the latch 2621 instead of the distance signal during cycle TI. be done.

In psych/L'Ti, the duration of signal 24a is longer than the duration in psych yv T z , so signal L
E becomes "0" level. Therefore, even if the control signal L8 is input, the output of the terminal Q of the latch 2613 remains at the "0" level. Furthermore, since the control signal Lo is not output, the distance signal operator ST stored in the latch 2621 also remains unchanged.

The duration of the signal 24a at psyche/L' T 4 is similar to that at psyche/l' T s and is similar to the duration at psyche/I'Ti. Therefore, the output of the terminal Q of the latch 2614 remains at "0" level.
The distance signal operator ST stored in 21 also remains unchanged.

The distance signal DTS 'I' stored in the latch 2621 is output from the latch 26 at the timing of the control signal LB output from the signal generation circuit 212 during this psych/1'T4.
22 and stored, and displayed on display devices 2721.2731 via decoders 272.273. At the same timing, 2611 latch terminals DI, D2, D3
, D4 are stored in the latch 261E and appear at its output terminals Q1, Q2, Q3, and Q4. In the example described above, only the input to the terminal D2 is at the Ill level, so the output from the corresponding terminal Q2 is at the "1" level, and the lamp 2712 indicating the transducer 12 is lit via the lamp driver 27]. As described above, among the four transducers 1.1 to 1-4, the lamp corresponding to the transducer 11 to 14 that detected the minimum distance is lit, and the detected distance is 2 digits. Displayed in numbers.

If equal minimum distances are detected in the two transducers 12.14, the latch 261 is activated at the second cycle/l' T t.
The Q terminal output of latch 2614 becomes rlj level in the fourth cycle /I/T4. In this fourth cycle/L'T4, the second cycle/l/T2
Since the distance signal DIST stored in the latch 2621 and the newly input distance signal DIST are the same, the output signal EQ of the "A-B" terminal of the comparator 26F52
, becomes "1" V-pel, and at the timing of the control signal L4, the output of the terminal Q of the latch 2617 other than the latch 2614 becomes "1" level ~, and the gate 261C! is not closed, and the input signal at terminal D2 of latch 261E remains at rlJ level. Therefore, at the timing of the signal Lm, the output signals of the terminals Q2 and Q4 corresponding to the input terminals D2 and D4 of the latch 261E become "1" level, and the lamp 2712.2'71 corresponding to the transducer 12.14
- lights up.

The distance detected by transducers 11 to 14 is all 2.5.
If it is longer than m, the comparator 2634's "A<B"
” terminal output becomes “1” level, display 2'721
, 2731 is turned off.

5 Also, if the minimum distance detected by the transducers 11 to 14 is 0.
If it is shorter than 3m, l' of comparator 2636
-A<B The output of the J terminal becomes "1" level, the lamp 2715 lights up, "5TOP" is displayed on the display instrument 2, and the buzzer 276 sounds.

When the gear of the otaku transmission is set to forward, the input of the G terminal of 263B becomes "1" level,
Display 2q21.2731 goes out.

In the above embodiments, all the device circuits are constructed of hardware, but this may be replaced by a microcomputer and its interface circuit. A flowchart in this case is shown in FIG. In this case, selection circuit 2
2. Transmission/reception circuit 23, detection circuit 24, and conversion circuit 25
A sag μm change corresponding to the sag μm is performed by interrupt processing every aom5ec.

In addition, in the embodiment, a single transmitting/receiving circuit, a detection circuit, and a conversion circuit are installed for multiple transducers, and these circuits are commonly used to sequentially transmit and receive waves from each transducer. Although the configuration is such that the distances of the transducers are sequentially compared, the above circuits may be provided in each of the transducers and the distances may be compared simultaneously.

Furthermore, although multiple transducers are used in the embodiment, a single transducer and a plurality of transducers are used instead, the reflected waves of the transducer are detected by the receiver, and the distance between each receiver is The configuration may be such that the receiver that shows the shortest distance and its distance are selectively displayed by calculating the shortest distance.

As described above, according to the present invention, when the vehicle is reversing, the driver can accurately know the distance to the obstacle using the display inside the vehicle, and can also get closer to the obstacle at the rear of the vehicle. Since you can see where the vehicle is moving, backing up in narrow spaces becomes extremely safe.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the overall configuration of the obstacle display device according to the present invention, Fig. 2 is a detailed block diagram of the selection circuit, transmission/reception circuit, detection circuit, conversion circuit, and control circuit, and Fig. 3 is a storage circuit and display. 4 is a time chart of various signals, FIG. 5 is an exploded perspective view of a display instrument, and FIG. 6 is a flow chart when the above circuit is replaced with a microcomputer program. 11.12.13.14... Ultrasonic transducer (
(wave transmitting means and wave receiving means) 2... Display instrument 23... Transmitting/receiving circuit (transmitting means and wave receiving means)
24...Detection circuit (detection means) 25...
・Conversion circuit (conversion means) Ward 26...Memory circuit (memory means)
. 27...Display circuit (display means)
Yabu's agent Patent attorney Kimima Ito 19 -1- Figure 5 Figure 6 438-

Claims (1)

[Claims] A plurality of ultrasonic wave receiving means arranged in parallel at the rear of the vehicle, an ultrasonic wave transmitting means provided integrally with or independently of these ultrasonic wave receiving means, and the above-mentioned wave transmitting means are excited to generate ultrasonic waves.I7 a transmitting means for processing the received signal of the reflected wave by the receiving means, a detecting means for detecting a time difference between transmission and reception of the ultrasonic wave, and a conversion means for converting the detected time difference into distance. A vehicle comprising: a delivery means having the minimum converted distance; a storage means for storing the distance; a reception means having the minimum distance stored in the storage means; and a display means for displaying the distance in digital numbers. Rear obstacle display device for use.