JPH0518787A - Display device - Google Patents

Abstract

PURPOSE:To make the indicated values of an analog display part and a digital display part for displaying the same content coincide or approximate to each other by providing the indicating characteristic of the digital display part with the hysteresis characteristic of the analog display part. CONSTITUTION:When signal pulses corresponding to the specific vehicle speed are supplied to an arithmetic control circuit 13 through a waveform shaping circuit 11 and an interface 12 in a delivery adjusting stage, a pointer is driven at a deflection angle corresponding to a false vehicle speed pulse signal in an analog display part 15, while the value corresponding to the indicated value is digital-displayed in a digital display part 20. Pulses are then inputted from the up-terminal or down-terminal of an indication correcting circuit 16 so as to match the indicated value of the display part 15. When the indicated value of the display part 15 and that of the display part 20 coincide with each other, a latch signal is inputted from a latch terminal, so that the circuit 13 stores the inputted pulse signal as a specific vehicle speed correction signal into an E<2>PROM 18, and performs signal processing by a built-in program at the actual travel time to make the indicated values of the display part 15, 20 coincide with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device for displaying the same contents on an analog display housed in, for example, a front meter case of a driver's seat and a digital display projected on a windshield.

[0002]

2. Description of the Related Art A conventional display device of this type is shown in FIG. In the figure, 1 is a vehicle speed sensor, 2 is a waveform shaping circuit for shaping the vehicle speed pulse signal from the vehicle speed sensor 1, 3 is a control circuit, 4 is a driver, 5 is provided in an upper recess of an instrument panel of a vehicle, and a front A digital display unit for projection display on glass, 6 a waveform shaping circuit for shaping the vehicle speed pulse signal from the vehicle speed sensor 1 to obtain a vehicle speed pulse, and 7 an F / V conversion circuit for F / V converting the vehicle speed pulse signal , 8 is F / V
From the analog signal from the conversion circuit 7, the SIN approximate signal and C
A SIN / COS conversion circuit that generates an OS approximate signal,
The SIN / COS conversion circuit 8 divides the measured frequency into sine and cosine, and the SIN approximate signal is passed through the SIN function generating circuit to the PWM chopper in the first pulse width modulation circuit constituting the pulse width modulation circuit 10. And C
In this configuration, the OS approximation signal is PWM choppered in the second pulse width modulation circuit that constitutes the pulse width modulation circuit 10 via the COS function generation circuit. An analog display unit 9 is housed in a meter case arranged in front of the driver's seat of the vehicle and driven by a PWM chopper-supplied SIN approximate signal and COS approximate signal supplied via a pulse width modulation circuit 10. It is a cross coil movement as.

Next, the operation of the above configuration will be described. The vehicle speed pulse signal from the vehicle speed sensor 1 is a waveform shaping circuit 6, F-V.
It is converted into a voltage signal via the conversion circuit 7. The converted voltage signal is converted into a pulse signal whose duty changes corresponding to the voltage value through the SIN / COS conversion circuit 8 and the pulse width modulation circuit 10 so as to drive the crossing coil movement 9, and the crossed signal is crossed. It is supplied to the coil movement 9.

On the other hand, the vehicle speed pulse signal is supplied to the digital display section 5 via the other waveform shaping circuit 2, the control circuit 3 and the driver 4 and is digitally displayed. The control circuit 3 performs signal processing according to the flowchart shown in FIG. That is, when the power is turned on, the process proceeds from the start step to the period measurement (step ST6-1), the vehicle speed pulse signal is counted, and further the data speed is averaged (step ST6-2) to average the vehicle speed every predetermined time. Is calculated and displayed digitally (step ST6-3)
Then, it is determined whether or not a predetermined time has elapsed since the previous display signal was supplied to the digital display unit 5, and if the predetermined time has not elapsed, the process returns to the cycle measurement (step ST6-1). If the predetermined time has elapsed, the measured value is converted into an integer (step ST6-4), and is supplied to the digital display unit 5 from the control circuit 3 by the display data transfer (step ST6-5) to measure the period. (Step ST6-
Return to 1).

[0005]

However, in such a conventional display device, there is a difference in resolution between the digital display section 5 and the analog display section 9, and a cross coil as the analog display section 9. There is a display error due to the difference (hysteresis angle) between the control angle of the electronic circuit of the movement and the indicated angle due to mechanical loss due to the bearing and the like. Therefore, when the digital display unit 5 and the analog display unit 9 perform display with the same signal input, there is a problem that the display contents of both display units are different and do not match.

The present invention has been made in view of such a conventional problem, and an object thereof is to make the indicated values of the analog display unit and the digital display unit displaying the same contents coincident with or close to each other.

[0007]

A display device according to the present invention has a structure in which a pointing characteristic of a digital display section has a hysteresis characteristic of an analog display section.

[0008]

In the display device according to the present invention, the display characteristics of the digital display section have a predetermined hysteresis characteristic so that the indicated values of the analog display section and the digital display section are approximated.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention. First, the configuration will be described. In FIG. 1, 1 is a vehicle speed sensor for detecting a vehicle speed, 11 is a waveform shaping circuit for inputting a vehicle speed pulse signal from the vehicle speed sensor 1 and shaping the waveform of the input vehicle speed pulse signal, 12 is an interface, 13 Is an arithmetic control circuit.

Reference numeral 14 is a SIN / COS conversion circuit to which a part of the output of the arithmetic control circuit 13 is supplied, and 15 is a SIN / CO conversion circuit.
A cross coil movement that constitutes an analog display unit is excited by the SIN approximate signal and the COS approximate signal from the S conversion circuit 14, and 16 is a finger degree correcting input circuit which is a finger degree correcting means. The input circuit 16 is provided with external terminals for up, down, and latch, and the operation control circuit 1 is connected to the external terminals for up, down, and latch.
Reference numeral 3 denotes a correction signal, that is, data for correcting an instruction error at each point of the indicated value of the analog display unit 15 based on the display characteristics of the digital display unit 20, an error factor of the cross coil itself, a deviation of the dial, and the like. Is entered. Further, correction data for causing the digital display unit 20 to have a hysteresis characteristic according to the rising and falling instruction characteristics of the analog display unit 15 is input.

Reference numeral 17 denotes an interface connected to the output terminal of the finger input correction input circuit 16, and reference numeral 18 is used to write correction signals sent from the interface 17 to the arithmetic control circuit 13 at each point of the indication characteristic of the digital display section 20. E ² PROM, 19 is a driver to which a digital display signal output from the arithmetic control circuit 13 is supplied, and 20 is a digital display section.

Note that the finger input correction input circuit 16 and the interface 17 are used only when setting correction data in the E ² PROM 18, and after setting, they are removed from the apparatus. In addition, the arithmetic control circuit 13 and the SIN
The COS conversion circuit 14 and the pulse width modulation circuit 21 form a signal processing circuit and are substituted by, for example, an internal device of a microcomputer.

Next, the operation of the above structure will be described. First, at the factory shipment adjustment stage, the waveform shaping circuit 11 outputs a specific pseudo vehicle speed pulse signal, for example, 20 Km / h, 60 Km / h,
The waveform shaping circuit 1 outputs a pulse signal corresponding to 100 km / h.
1. When supplied to the arithmetic and control circuit 13 via the interface 12, the pointer is rotationally driven at the deflection angle corresponding to the analog vehicle speed pulse signal input to the analog display unit 15,
While being displayed, a value corresponding to the indicated value is also digitally displayed on the digital display section 20.

Therefore, the person who makes the adjustment is the analog display unit 1.
Up of the finger input correction input circuit 16 so as to match the indicated value of 5.
When a pulse is input from the terminal or the down terminal and the two values match, the arithmetic control circuit 13 inputs the latch signal from the latch terminal, and the arithmetic control circuit 13 outputs the input pulse as a correction signal of, for example, 20 Km / h. ² PROM
Remember in 18. This operation is performed at several points between the minimum scale and the maximum scale while increasing the indicated value and performing the same operation while decreasing the indicated value to pair the vehicle speed pulse signal supplied from the vehicle speed sensor 1 and its correction value. E ² PROM
18 is stored as a reference table.

E ² PROM stored as described above
When a device equipped with 18 is mounted on a vehicle and travels, a vehicle speed pulse signal from the vehicle speed sensor 1 is supplied to the arithmetic control circuit 13, and the signal is processed and displayed as follows by the built-in program.

That is, in FIG. 2, when the power is turned on, from the start step to the cycle measurement step ST1-
1, the vehicle speed at each time is calculated in the data averaging step ST1-2, and the next control angle converting step ST1.
-3, the rotation angle of the pointer of the cross coil movement 15 is calculated, and the SIN / CO with respect to the rotation angle calculated in the SIN / COS / PWM value calculation step ST1-4 is calculated.
The S output control PWM value is calculated.

In the PWM output control step ST1-5, a pulse signal subjected to duty control is supplied to the cross coil movement 15. Then, in the digital display control step ST1-6, if the predetermined time, for example, 0.3 seconds, has not elapsed from the previous display output, the cycle measurement step S
Returning to T1-1, if the predetermined time has elapsed, the measurement value is converted into an integer in the step ST1-7 for converting the measurement value into an integer, and then the process proceeds to the hysteresis processing step ST1-8. That is, in the hysteresis processing step ST1-8, it is judged whether the measured value is up to down or equal (0) with respect to the current display value (step ST1-8-1), and the dow
The measured value is incremented by 1 only at the time of n (step ST1-8
-2), that is, the hysteresis angle Δθ is shifted, and the others are used as new display values without changing the measured values (step ST
1-8-3, ST1-8-4), display data is transferred (step ST1-9) and displayed.

Generally, since the hysteresis angle Δθ of the cross coil movement 15 is about 1 ° to 2 °, the instrument displaying 0 to 180 Km / h at a deflection angle of 270 ° as shown in FIG. Δθ≈1 Km / h. Therefore, in the case of the conventional device which does not perform the hysteresis processing as shown in FIG. 6, the characteristics of the display value of the analog display unit 15 and the display value of the digital display unit 20 are as shown in FIG.
+1 in the ascending (up) direction and -1 in the descending (down) direction
Therefore, the maximum instruction difference is ± 1 and the error is large.

However, according to the present invention, by performing the hysteresis process as shown in FIG. 4, the correlation between the digital display value and the analog display value with respect to the input signal is the operating point exhibiting the same value N, and is digital in the up direction. Adjustment is made so that the analog display value of 1/2 separation power (0.5 Km / h) of the display value is higher and the analog display value is lower in the down direction. As a result, both up / down have a maximum indication difference of ± 0.5 Km / h, and the display error between the digital display value and the analog display value is half that of the conventional device.

[0020]

As described above, according to the present invention, the signal processing circuit for creating the analog display signal and the digital display signal based on the detection output from the vehicle speed sensor and the display signal from the signal processing circuit are respectively provided. In a display device having an analog display unit and a digital display unit for displaying separately, the analog display unit having a rising instruction characteristic and a descending instruction characteristic different from the rising instruction characteristic, the rising and falling instruction characteristics of the digital display unit are Since it has a hysteresis characteristic in accordance with the rising and falling instruction characteristics of the analog display section, there is an effect that the instruction values of the analog display section and the digital display section can be approximated.

[Brief description of drawings]

FIG. 1 is a block diagram showing a display device according to an embodiment of the present invention.

FIG. 2 is a flow chart for explaining the operation of the device of the present invention.

FIG. 3 is a diagram showing an operation range of an instrument instruction.

FIG. 4 is a relationship diagram of digital display with respect to an input signal according to the device of the present invention.

FIG. 5 is a block diagram showing a conventional display device.

FIG. 6 is a flowchart illustrating the operation of the conventional device.

[Explanation of symbols]

 10 vehicle speed sensor 15 analog display unit 20 digital display unit 21 signal processing circuit

Claims (1)

Claim: What is claimed is: 1. A signal processing circuit (13, 14, 21) for producing an analog display signal and a digital display signal based on a detection output from a vehicle speed sensor (1), and the signal processing circuit (13, 14, 21). An analog display unit (15) and a digital display unit (16) for individually displaying display signals from the respective display units (13, 14, 21), the analog display unit (15) having a rising instruction characteristic and the rising instruction characteristic. In a display device having different descending instruction characteristics, the ascending and descending instruction characteristics of the digital display section (16) are different from each other in the analog display section (15).
A display device having a hysteresis characteristic according to the rising and falling instruction characteristics of the display device.