JPH0436390B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a level display device that displays levels of battery voltage, temperature, etc., for example.

[Prior art and its problems]

As a conventional level display device of this type, there is one that performs A/D (analog/digital) conversion of analog values such as battery voltage and temperature, and displays the converted data digitally on a liquid crystal panel. However, since the above conventional level display device uses an A/D conversion circuit, there is a problem in that the circuit configuration becomes complicated.

[Object of the Invention] The present invention has been made in view of the above points, and an object of the present invention is to provide a level display device that can reliably display a level with a simple configuration.

[Embodiments of the invention]

An example in which the present invention is implemented in a thermometer will be described below with reference to the drawings. In FIG. 1, 1 is a battery, and a thermistor 2 for temperature detection is connected to the battery 1 via a resistor 3. Further, the battery 1 is supplied to a waveform generation circuit 4. This waveform generating circuit 4 generates a rectangular wave signal of a constant period, and its output signal is sent directly and via an inverter 5 to a display driver 6. Further, the output of the inverter 5 is output from the flip-flops 7a to 7.
d. The output of the flip-flop 7a is sent to the display driver 6, and the outputs of the other flip-flops 7b to 7d are sent to the flip-flop 8.
It is input to a to 8c. The output of the flip-flop 8a is sent to the display driver 6, and the outputs of the other flip-flops 8b and 8c are input to flip-flops 9a and 9b. Further, the output of the flip-flop 9a is sent to the display driver 6, and the output of the other flip-flop 9b is sent to the display driver 6 via the flip-flop 10.
The flip-flops 7a to 7d, 8a to 8c,
Reference numerals 9a, 9b, and 10 are delayed flip-flops that operate in synchronization with the clock pulse A. Further, the voltage V ₀ generated at the connection point between the thermistor 2 and the resistor 3 is input to the display driver 6 . The level display section 11 is driven to display by this display driver 6. This level display section 11 is constructed of, for example _, a liquid crystal panel, and as shown in FIG _. is provided, and the second electrode substrate 14
A common electrode 15 common to the segment electrodes 113 ₁ to 13 ₅ is provided. The display driver 6 outputs the common signal COM based on the signal directly input from the waveform generation circuit 4, and outputs the common signal COM from the inverter 5, flip-flops 7a, 8a, 9a,
Segment signal by the signal given from 10
Output Seg1 to Seg5. In this case, the display driver 6 operates using, for example, the input voltage V ₀ as the power supply voltage, the common signal COM, the segment signal Seg
The voltage levels of Seg1 to Seg5 change according to the input voltage _V0 .

Next, the operation of the above embodiment will be explained. The thermistor 2 has negative characteristics with respect to temperature changes, and its resistance value decreases as the temperature rises.
Therefore, when the temperature is low, the resistance value of the thermistor 2 is large, and the voltage V ₀ divided by the thermistor 2 and the resistor 3 is low. Then, as the temperature rises, the resistance value of the thermistor 2 becomes smaller, so the divided voltage V ₀ , that is, the input voltage V ₀ of the display driver 6 also rises.

On the other hand, the waveform generating circuit 4 constantly outputs a rectangular wave signal with a constant period. This rectangular wave signal is sent to the display driver 6, and is supplied to the level display section 11 as a common signal COM shown in FIG. Further, the rectangular wave signal outputted from the waveform generating circuit 4 is inverted by an inverter 5, and then directly sent to a display driver 6.
0 to the display driver 6, and as shown in FIG. 4, the signals are sequentially supplied to the level display section 11 as segment signals Seg1 to Seg5 having different phases. In this case, the common signal COM and segment signals Seg1 to Seg1 output from the display driver 6
The voltage level of Seg5 is equal to the input voltage _V0 . Therefore, the drive signals COM- _Seg1 , COM- _Seg2 , and
The voltage waveforms of COM-Seg3, COM-Seg4, and COM-Seg5 are as shown in FIG. That is,
Of the effective voltages V _S 1 to V _S 5 of the drive signals for each segment electrode 13 ₁ to 13 ₅ , V _S 1 is the largest;
V _S 2, V _S 3, ... decrease in this order, but the time width is 6:1 with respect to the period of clock pulse _A.
Therefore, it takes the following value for the input voltage V ₀ .

V _S 1=V ₀ V _S 2=√5/6V ₀ ≒0.91V ₀ V _S 3=√4/6V ₀ ≒0.82V ₀ V _S 4=√3/6V ₀ ≒0.71V ₀ V _S 5=√ 2/6V ₀ ≒ 0.58V ₀ However, as shown in FIG. 3, the level display section 11 is in a non-lighting state when the effective voltage V _S is below a certain value, for example, V _S L. , V _S H or higher, the light turns on (for example, black). In this case, there is a predetermined voltage width between the values V _S L and V _S H. When the effective voltage V _S is in a transient state between V _S L and V _S H, the level display section 11 is in an intermediate color state (for example, gray). Therefore, the lines a to e in Fig. 3 indicate that the input voltage V ₀ is the maximum voltage.
The lighting state of each of the segment electrodes 13 ₁ to 13 ₅ is shown when the voltage changes from V ₀ 1 to the minimum voltage V ₀ 6 at regular intervals. That is, if the input voltage V ₀ is
In the case of V ₀ 1, the effective voltages V _S 1 to V _S 5 for the segment electrodes 13 ₁ to 13 ₅ all exceed the value V _S H, and the segment electrode 13
₁ to 13 ₅ are all lit. Also, when the input voltage V ₀ is V ₀ 2, the effective voltage V _S 1 to V _S 2 is the value
Since the effective voltage V _S 5 is between the values V _S L and V _S H above V S H, the segment electrodes 13 ₁ to 13 ₄ are in the lighting state as shown in FIG _. 5b.
₅ becomes a transient state. Similarly, input voltage V ₀
As the voltage decreases to V ₀ 3, V ₀ 4, V ₀ 5, and V ₀ 6, the effective voltage for the segment electrodes 13 ₁ to 13 ₅ decreases sequentially as shown by straight lines a to e in FIG. The lighting state changes as shown in FIGS. 5c to 5f. When the input voltage V ₀ decreases to V ₀ 6, the effective voltages V _S 1 to V _S of the segment electrodes 13 ₁ to 13 ₅
5 are all below the value V _SL , and all the segment electrodes 13 ₁ to 13 ₅ are in the non-lighting state as shown in FIG. 5 f.

As described above, the segment electrodes 13 ₁ to 1 in the level display section 11 change depending on the change in the input voltage V ₀ .
The lighting status of 3 _{and 5} changes, and the temperature status can be displayed in levels.

In addition, in the above example, the case where it was applied to a thermometer was shown, but other examples, such as a solar cell,
Using CDS elements, it can also be applied to illumination meters, battery voltage level meters, etc. Further, the circuit that generates the display drive signal is not limited to the above-mentioned embodiment, and may be any circuit that generates a plurality of drive signals having different effective values. Furthermore, the number, shape, arrangement method, etc. of the segment electrodes can be set arbitrarily.

〔Effect of the invention〕

As described above, according to the present invention, n display segments are arranged, n types of drive signals having different effective values are applied to the display segments based on the detected voltage, and the lighting state of the segments is Since the level of the detected voltage is displayed by the above, the level display device does not require the conventionally used A/D conversion circuit and can reliably display the level with a simple circuit configuration. can be provided.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention; FIG. 1 is a circuit configuration diagram, FIG. 2 is an electrode configuration diagram of a display section, and FIG. 3 is a diagram showing the relationship between the effective voltage applied to the display section and the lighting state. 4 is a timing chart showing the waveform of the display drive signal, and FIG. 5 is a diagram showing the relationship between the detected voltage and the display state. 1...Battery, 2...Thermistor, 4...Waveform generation circuit, 6...Display driver, 7a to 7d, 8a
~8c, 9a, 9b, 10...Flip-flop, 11...Level display section, 12...First _electrode substrate, _131-135 ...Segment electrode, 14...
Second substrate, 15... common electrode.

Claims (1)

[Claims] 1. A display section including n liquid crystal display segments arranged in a row, a voltage output means for outputting power for level display, and a level display outputted by the voltage output means. A display drive method in which n types of display drive signals with different effective values are created depending on the difference in drive voltage supply time, and are sent to the n liquid crystal display segments in order of the magnitude of the effective value. A level display device comprising: means for displaying a level of the voltage output by the voltage output means according to a lighting mode of a liquid crystal display segment of the display section.