JP3160014B2 - Display device - Google Patents

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 a meter case in front of a driver's seat and a digital display projected on a windshield, for example.

[0002]

2. Description of the Related Art As a conventional display device of this type, for example, there is one as 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 concave portion of an instrument panel of the vehicle, A digital display unit for projecting and displaying on a glass, a waveform shaping circuit 6 for waveform shaping a vehicle speed pulse signal from the vehicle speed sensor 1 to obtain a vehicle speed pulse, and an F / V conversion circuit 7 for F / V converting the vehicle speed pulse signal. , 8 is F / V
From the analog signal from the conversion circuit 7, the SIN approximation signal and C
A SIN / COS conversion circuit that generates an OS approximation signal,
The SIN / COS conversion circuit 8 divides the measured frequency into a sine and a cosine, and converts the SIN approximation signal into a PWM chopper in a first pulse width modulation circuit constituting the pulse width modulation circuit 10 via a SIN function generation circuit. And C
In this configuration, the OS approximation signal is subjected to PWM chopper in a second pulse width modulation circuit constituting the pulse width modulation circuit 10 via a COS function generation circuit. Reference numeral 9 denotes an analog display unit housed in a meter case disposed in front of the driver's seat of the vehicle and driven by a PWM choppered SIN approximation signal and a COS approximation signal supplied via a pulse width modulation circuit 10. As a cross coil movement.

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

On the other hand, the vehicle speed pulse signal is supplied to a digital display unit 5 via the other waveform shaping circuit 2, control circuit 3, and 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 cycle measurement (step ST6-1), the vehicle speed pulse signal is counted, and the vehicle speed averaged at predetermined time intervals by data averaging (step ST6-2). Is calculated and displayed digitally (step ST6-3).
It is determined whether or not a predetermined time has elapsed since the last time the display signal was supplied to the digital display unit 5. 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 by converting the measured value into an integer (step ST6-4), and is supplied from the control circuit 3 to the digital display unit 5 through display data transfer (step ST6-5), and the period measurement is performed. (Step ST6-
Return to 1).

[0005]

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

The present invention has been made in view of such a conventional problem, and has as its object to match or approximate indicated values of an analog display unit and a digital display unit that display the same contents.

[0007]

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

[0008]

According to the display device of the present invention, the display characteristics of the digital display unit have a predetermined hysteresis characteristic, and the indicated values of the analog display unit and the digital display unit 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 one embodiment of the present invention. First, the configuration will be described. In FIG. 1, reference numeral 1 denotes a vehicle speed sensor for detecting a vehicle speed; 11, 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, an interface; Is an arithmetic control circuit.

Reference numeral 14 denotes a SIN / COS conversion circuit to which a part of the output of the operation control circuit 13 is supplied, and 15 denotes a SIN / COS conversion circuit.
A cross-coil movement which constitutes an analog display unit which is excited by the SIN approximation signal and the COS approximation signal from the S conversion circuit 14, respectively. Reference numeral 16 denotes a finger correction input circuit which is finger correction means. The input circuit 16 is provided with external terminals for up, down, and latch.
3 shows a correction signal, that is, data for correcting an indication error at each point indicated by 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 displacement of the dial, and the like. Is entered. Further, correction data for causing the digital display unit 20 to have a hysteresis characteristic in accordance with the ascending and descending instruction characteristics of the analog display unit 15 is input.

Reference numeral 17 denotes an interface connected to the output terminal of the finger correction input circuit 16, and reference numeral 18 denotes a correction signal sent from the interface 17 to the arithmetic and control circuit 13 at each point of the indicated characteristic of the digital display unit 20. An 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 unit.

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

Next, the operation of the above configuration will be described. First, at the factory shipment adjustment stage, the waveform shaping circuit 11 supplies a specific similar vehicle speed pulse signal, for example, 20 km / h, 60 km / h,
A pulse signal corresponding to 100 km / h is converted to a waveform shaping circuit 1
1. When supplied to the arithmetic and control circuit 13 via the interface 12, the hands of the analog display unit 15 are driven to rotate at a deflection angle corresponding to the input analog vehicle speed pulse signal,
On the other hand, a value corresponding to the indicated value is also digitally displayed on the digital display unit 20 while being displayed.

[0014] Therefore, the person who adjusts the analog display unit 1
5 of the finger 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 values match, a latch signal is input from the latch terminal, so that the arithmetic and control circuit 13 converts the input pulse to a correction signal of, for example, 20 km / h. ² PROM
Store it 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 with its correction value. E ² PROM
18 is stored as a reference table.

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

That is, in FIG. 2, when the power is turned on, a cycle measuring step ST1-
The vehicle speed at each time is calculated in a data averaging step ST1-2, and the control angle conversion step ST1 is performed.
In -3, the rotation angle of the pointer of the cross coil movement 15 is calculated, and SIN · CO with respect to the rotation angle calculated in the SIN · COS · PWM value calculation step ST1-4.
An S output control PWM value is calculated.

In the PWM output control step ST1-5, the pulse signal subjected to the duty control is supplied to the cross coil movement 15. In the digital display control step ST1-6, if a predetermined time, for example, 0.3 seconds has not elapsed from the previous display output, the cycle measurement step S1
Returning to T1-1, if the predetermined time has elapsed, the measurement value is converted to an integer in the measurement value conversion step ST1-7, and then the process proceeds to the hysteresis processing step ST1-8. That is, in the hysteresis processing step ST1-8, it is determined whether the measured value of the current display value is up or down or equal (0) (step ST1-8-1).
Only at the time of n, the measured value is incremented by 1 (step ST1-8).
-2), that is, the hysteresis angle is shifted by △ θ, and the other values are used as new display values as they are as measured values (step ST).
1-8-3, ST1-8-4), display data transfer is performed (step ST1-9), and display is performed.

Normally, the hysteresis angle △ θ of the crossed coil movement 15 is about 1 ° to 2 °. Therefore, as shown in FIG. Δθ ≒ 1 km / h. Therefore, in the case of the conventional device that does not perform the hysteresis process 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.
Ascending (up) direction is +1 and descending (down) direction is -1.
And the maximum indicated difference of ± 1 results in a large error.

According to the present invention, the correlation between the digital display value and the analog display value with respect to the input signal is obtained by performing the hysteresis processing as shown in FIG. Adjustment is made so that the analog display value of 1/2 resolution (0.5 km / h) of the display value is higher and lower in the down direction. As a result, both the up / down have a maximum indicated difference of ± 0.5 km / h, and the display error between the digital display value and the analog display value is halved compared to the conventional device.

[0020]

As described above, according to the present invention, a signal processing circuit for generating an analog display signal and a digital display signal based on a detection output from a vehicle speed sensor, and a display signal from the signal processing circuit, respectively. An analog display unit and a digital display unit for displaying separately, wherein the analog display unit has an ascending instruction characteristic and a descending instruction characteristic different from the ascending instruction characteristic. Since the analog display section has a hysteresis characteristic in accordance with the ascending and descending instruction characteristics, the indicated values of the analog display section and the digital display section can be approximated.

[Brief description of the drawings]

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

FIG. 2 is a flowchart for explaining the operation of the apparatus of the present invention.

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

FIG. 4 is a diagram showing a relationship between an input signal and a digital display by 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]

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

Continuation of the front page (56) References JP-A-53-41276 (JP, A) JP-A-4-89522 (JP, A) Japanese Utility Model Application No. Sho 60-88216 (JP, U) Japanese Utility Model Application Utility Model No. Sho 58-2714 (JP) , U) Fully open sho 56-9011 (JP, U) Fully open sho 55-135913 (JP, U) Fully open sho 55-86965 (JP, U) Fully open sho 50-6669 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01D 7/00 302

Claims (1)

(57) [Claims] A signal processing circuit (13, 14, 21) for generating 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 section (15) and a digital display section (16) for respectively displaying the display signals from the display section, respectively, wherein the analog display section (15) has an ascending instruction characteristic and a descending instruction characteristic different from the ascending instruction characteristic. In the display device, the ascending and descending instruction characteristics of the digital display section (16) are controlled by the analog display section (15)
A display device having a hysteresis characteristic in accordance with the upward and downward instruction characteristics.