JPH039213A - Odometer - Google Patents

Abstract

PURPOSE:To easily confirm the number of display digits and to easily read display contents by making a display of digits which are not used to indicate a travel distance different in brightness from a display of digits which indicate the travel distance. CONSTITUTION:When a three-digit travel distance is displayed, signal train data SG2 corresponding to the travel distance and a shift lock signal SG1 are outputted to a display driver IC3. When digits which are not used to indicate the travel distance display 0, signal train data SG3 and a shift lock signal SG1 are outputted to a display driver IC4. When the signal train input is com pleted, a mu-CPU1 makes a three-digit display on a fluorescent display tube 2 through a driving circuit 10. At this time, a blank signal SG5 is outputted and when the driver IC4 outputs a blank signal SG6 which makes an illumina tion time shorter than that of the driver IC3, the digits of the display are un changed in brightness and digits of 0 are decreased in brightness.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an odometer, and more particularly to an electronic odometer or trip meter.

[Prior Art] In conventional electronic odometers, the upper digits that are not used for display are left as "O" because of the convention of mechanical odometers and the importance of the number of displayed digits. That is, general 1
If the number of miles traveled is small compared to the maximum 6-digit display in km or 1 mile units, rOJ is displayed in the upper digits that are not used for display, similar to a mechanical odometer, for example.

On the other hand, in electronic trip meters, if there is rOJ in the upper digits that are not used for display, there are problems such as difficulty in reading the mileage.
The rOJ at the beginning of the 1-mile unit was displayed in up to 4 digits and was erased. In general, JP-A-58-123417 and JP-A-58-189510 disclose a technique for displaying an odometer and a trip meter on one display section, and this technique is used to distinguish between the displayed contents. Therefore, the upper digits not used for display were displayed as rOJ or turned off.

[Problems to be Solved by the Invention] However, these devices do not make it easy to check the number of digits displayed, nor do they make it easy to read the displayed content, so it is difficult to say that they are technically satisfactory. Ta.

An object of the present invention is to provide an odometer in which the number of displayed digits can be easily confirmed and the displayed contents can be easily read.

[Means for Solving the Problems] The present invention provides an odometer equipped with a display element group forming a number of digits corresponding to a maximum mileage distance, in which the display element group of the digit indicating the current mileage is The gist of the present invention is an odometer in which a drive circuit is provided to change the brightness of at least one of the display elements of the digits that are not used to display the remaining mileage.

[Operation] The brightness of at least one of the display element groups of the digits that are not used to display the remaining mileage is changed relative to the display element group of the digit that displays the current mileage.

[Example] An example embodying the present invention will be described below with reference to the drawings.

FIG. 1 shows an electronic odometer and trip meter circuit using a common display. The circuit is a distance sensor (
a microcomputer (distance counting circuit) 1 constituting a drive circuit that counts signals from the route shown in the diagram and integrates the distance;
It is composed of a fluorescent display tube 2 as an indicator for displaying the distance traveled, and two systems of display driver ICs 3 and 4 forming a drive circuit for driving the fluorescent display tube 2. As shown in Fig. 5, the fluorescent display tube 2 can display 6 digits (2a to 2f>) corresponding to the maximum travel distance, and each digit 2a to 2f can display 7 segments. The microcomputer 1 also inputs a switching signal for switching between the odometer display and the 1-lip meter display.

The display driver IC3 includes a shift register 5, a data latch circuit 6, and a drive circuit 7. Similarly, the display driver IC4 includes a shift register 8, a data latch circuit 9, and a drive circuit 10. The shift registers 5 and 8 receive the data shift clock SG1 output from the microcomputer 1 and rOJ synchronized therewith.
Or signal string data SG2 of "1". Input SG3 respectively. The shift registers 5 and 8 then use the signal string data SG2. The signal string by SG3 is stored and output to data latch circuits 6 and 9.

Data latch circuits 6 and 9 are connected to shift registers 5 and 9 by data latch signal SG4 from microcomputer 1.
The output of 8 is stored and output to the drive circuit 7.10. The drive circuits 7 and 10 convert the output into the lighting voltage of the fluorescent display tube 2 if rlJ (H level), and rOJ
(L level), each segment of the fluorescent display tube 2 is turned off by setting the output to a high impedance state.

Further, the drive circuits 7 and 10 are connected to the microcomputer 1.
The blank signal SG5. Enter SG6,
If the signal level is in the rHJ state, the output is set to a high impedance state regardless of the signal strings stored in the shift registers 5, 8 and data latch circuits 6, 9,
All digits of the fluorescent display tube 2 are turned off.

The two systems of display driver ICs 3 and 4 have their corresponding output terminals (for example, Pl and P2> connected to each other, and are further connected to an anode electrode of one segment (for example, 31) of the fluorescent display tube 2. As a result, each segment of the fluorescent display tube 2 can be illuminated by 1 (H level) of the signal train of either one of the display driver ICs 3 and 4. In addition, the display driver IC 3 can be illuminated by the blank signal SG5.3G6. , 4, and the lighting content of the fluorescent display tube 2 can be changed.

In the conventional lighting system, one display drive IC (one of three or four) was used.

Next, the operation of the odometer configured in this way will be explained. At this time, a case will be explained taking as an example a case where the display shown in FIG. 6 is performed as the odometer display and the display shown in FIG. 7 is performed as the trip meter display.

First, when the microcomputer 1 displays the three-digit (2d to 2f) mileage value shown in FIG.
and display driver IC3 for data shift clock SG1
output to shift register 5. In addition, when the digits (2a to 2c) not used for the mileage shown in Fig. 3 are displayed as rOJ, the signal string data SG3 of the signal string that has the same display
and data shift lock SG1 are output to the shift register 8 of the display driver IC4. 2-system display driver I
When the input of the signal string to C3 and C4 is completed, the microcomputer 1 outputs the data latch signal SG4 to cause the data latch circuits 6 and 9 to store and hold the data, and the drive circuits 7 and 4
The distance traveled is displayed on the fluorescent display tube 2 via 10.

Here, blank signal SG5. SG6 has a duty ratio of T2/TI at 100Hz or higher, as shown in Figure 4 (a>).
If the same signals are used, the display outputs of the display driver ICs 3 and 4 (Figures 2 and 3) will be a logical sum display (Figure 5) with the same brightness, and the display will not flicker. invisible.

Further, a blank signal SG5 shown in FIG. 4(a) is output,
In addition, the display driver IC4 shown in FIG. 4(b) has a blank signal SG6 whose lighting time is shorter than that of the display driver IC3, that is, a blank signal SG6 with a duty ratio of T3/TI (However, the blank signal SG6 with a duty ratio of T3<T2> When you output
The output of the display driver IC3 is output with the same brightness, and the output of the display driver C4 is output to the fluorescent display tube 2 with a lower brightness than the display driver IC3. As a result of calculating the logical sum, the fluorescent display tube 2 displays a display as shown in FIG.

Moreover, when the microcomputer 1 inputs the switching signal,
In a similar manner, the 1 to lip meter display as shown in FIG. 7 is performed. When displaying the trip meter, a maximum of four digits are displayed, and the brightness of digits not used for display is lowered by the method described above. That is, in Figure 7, two digits (2
Display the mileage in 2 digits (2G, 2d).
The rOJ display is performed at low brightness.

In this way, in this embodiment, when displaying the odometer, each segment (display element group) can form six digits corresponding to the maximum mileage, and each segment of the digits that displays the current mileage is , the brightness of segments 1 to 1 of the rOJ formation in the digits that are not used to display the remaining mileage is lowered, and when displaying the trip meter, each segment (display element group) corresponds to the maximum mileage. do 4
For each segment 1 (display element group) of the digits that can form digits and display the current mileage, the brightness of the segments for rOJ formation of the digits that are not used to display the remaining mileage is lowered. . As a result, distance values are emphasized and
The distance becomes easier to read and at the same time the number of effective digits becomes clear.

Furthermore, it is an odometer with a 6-digit display, and a 4-digit display.
The trip meter can be easily identified by the digit display. Also, blank signal SG5. By changing the duty ratio of SG6, it is possible to arbitrarily change the brightness of bright areas (distance) and dark areas (significant digits) within the same display, making it easy to cope with nighttime dimming. .

Note that this invention is not limited to the above embodiments,
For example, in the above embodiment, two static display driver ICs are used, but it is possible to use a 1/2 dynamic lighting driver, in which case the number can be reduced to one.

Furthermore, the microcomputer 1 may also be included in a two-element configuration with a display.

Also, as a display in digits that are not used for mileage display, rO
In addition to J, "-" may be displayed with low brightness. or,
In addition to the fluorescent display tube, an LED may be used as the display.

[Effects of the Invention] As described in detail above, according to the present invention, excellent effects are achieved in which the number of displayed digits can be easily confirmed and the displayed contents can be easily read.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram of the odometer of the embodiment, Figure 2 is a diagram for explaining display operation, Figure 3 is a diagram for explaining display operation, and Figure 4 (a>, (b)). 1 is a diagram showing a blank signal, FIG. 5 is a diagram for explaining the display operation, FIG. 6 is a diagram for explaining the display operation, and FIG. 7 is a diagram for explaining the display operation. 1 is a diagram for explaining the display operation. A microcomputer constitutes a drive circuit, 2 is a fluorescent display tube, and 3 is a display driver IC 1 that constitutes a drive circuit.
4 is a display driver IC constituting a drive circuit.

Claims (1)

[Scope of Claims] 1. In an odometer equipped with a display element group forming a number of digits corresponding to the maximum mileage, the remaining mileage is displayed for the display element group of the digit displaying the current mileage. An odometer comprising a drive circuit that changes the brightness of at least one of the display element groups of digits that are not used for display.