JPS59157617A - Display device - Google Patents

Abstract

PURPOSE:To obtain such display that display blocks vary stepwise in optical variation amount by dividing a display area into display blocks each consisting of a specific number of segments and controlling voltage application to segments corresponding to each display block. CONSTITUTION:Signals corresponding to displays shown in figures (b), (c), and (d) are applied cyclically while effective voltages of respective display blocks are controlled so as to form a bar graph display in a display pattern with several gradations. A display block A is brightest and regarded as an indication top, and blocks are decreased in brightness gradually in the increasing direction of the display area. In this case, the decisions on how many blocks the display area is divided into and further how many segments form each displat block are made according to variation in event to be measured.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a part-graph display device that indicates changes in events by selectively displaying a plurality of aligned display segments.

BACKGROUND ART Conventionally, a bar graph display device in which a plurality of display segments are arranged has been commonly used as a device for visually recognizing changes in a measured event in an analog manner.

For example, by taking advantage of the advantage of an analog display, which allows you to intuitively read the driving speed of a car by comparing it with the scale on the dial that corresponds to the rotational position of the pointer, we can change the display area of a bar graph display device or move display segments. There are so-called electronic display instruments that have the same display effect as the above-mentioned analog display.

These bar graph display devices utilize light emission control of display segments using self-luminous elements such as light-emitting diodes and fluorescent display tubes, or light transmittance characteristics of light-receiving (reflective, transmissive display) elements such as liquid crystal display devices. A device that allows visual recognition of various optical changes, typified by shutter control, is generally used.

FIG. 1 is a diagram illustrating a conventional display system for displaying, for example, the running speed of a car using a bar graph display device.
A bar graph display: a 3 in which a plurality of display segments 2 are arranged is formed on the display substrate 1, and an index section 4 consisting of numbers or scales serving as a guide for reading is formed, for example, by printing along this bar graph display. Now, if the display substrate 1 is a liquid crystal display device, each display segment 2 is formed as an opposing electrode part, and when an event to be measured occurs, the segment part to which a voltage is selectively applied in accordance with the traveling speed becomes a transparent state. It is configured to perform a lighting display using light irradiated from a rear light source through a transflective plate disposed behind it, or alternatively, the bar graph display section 3 is normally kept in a transmitting state and a voltage is selectively applied. The segment portion becomes □ non-transparent, and display is performed by increasing or decreasing the dark portion.

Therefore, a change in brightness appears in the bar graph display section 3 due to the difference in light transmittance between the display area formed by the display segment 2 up to the scale position corresponding to the traveling speed and the remaining display area, and this bright and dark area changes. An analog-like information display can be obtained by increasing or decreasing the amount.

Furthermore, if the display segments 2 arranged on the display substrate 1 are arranged as light emitting diodes, the light emission of the display segments 2 can be controlled up to the scale position corresponding to the running speed, or the bar graph display section 3 which is always in a light emitting state can be controlled. A similar analog display can be obtained by controlling the lights to turn off up to the above scale position.

Such bar graph display devices, which indicate changes in a measured event by selectively displaying a plurality of aligned display segments, have been applied in a wide range of fields with various display patterns due to their analog display effects. For example, from the central part of the bar graph display part 3, such as the speedometer of a car mentioned above, which displays by increasing or decreasing the display area in one direction, or the volume display of an audio device, as shown in FIG. 1(b). Examples include those that indicate by the amount of optical change that spreads from side to side.

However, the display of the measured event on such a bar graph display device is simply a change in the bright/dark area ratio, in other words, a movement of the boundary line between the bright display area and the dark display area in the bar graph display area 3. It is necessary to make the contrast between light and dark clear in order to improve the interpretation of values. For this reason, a method of increasing the brightness of the bright display area has been considered, but since the bright display area tends to visually feel relatively wider than the dark display area, direct reading of the indicated value based on the bright/dark area ratio is also accurate. There may be cases where the quality is lacking. Furthermore, the brightness of each display segment 2 serving as a bright display portion is given uniformly,
Since the configuration is such that the display is simply a change in the brightness/darkness area ratio, even if it is possible to intuitively read the change in the measured event within an approximate range, it may not be possible to read it, and in appearance it is just a brightness/darkness area. Since it is an increase/decrease display, it can only give the impression of a monotonous analog display, and has the drawback of lacking the luxury required of electronic displays.

The present invention aims to provide a display device that has good visibility and excellent reading accuracy by making use of the analog display effect of a bar graph display device. It is characterized by varying the amount of optical change in a continuous or stepwise manner, giving an impression suggesting the rising direction of the display area corresponding to the indicated value, or giving a luxurious design through an afterimage display effect. It is.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the accompanying drawings regarding a speed needle for an automobile.

The speed hand in this embodiment uses a liquid crystal cell as its display element, and has a display pattern in which the display area corresponding to the running speed is brightly displayed.

In this case, the brightness of the display area as a bright display area in the liquid crystal cell can be controlled using the light transmittance characteristic of the liquid crystal cell with respect to the applied voltage. Preferably, a guest-host type liquid crystal cell is used, which has a wide control range and can obtain good contrast by selecting the dyes contained, but for the sake of simplicity, here, a TN type liquid crystal cell with polarizers on both sides is used. Display brightness control using the relationship between transmittance and polarization axis rotation angle with respect to applied voltage as shown in FIG. 2 is adopted.

Furthermore, as a method of displaying the display area determined according to the running speed with stepwise changes in brightness, cyclic voltage application control corresponding to several step display patterns as shown in Fig. 3 is used. It shall be a composite display. That is, in order to obtain a display with three levels of brightness changes as shown in FIG.
The configuration is such that the effective voltage of each display block is controlled by controlling the application of display signals to selective display segments indicated by dl. In this case, the voltage application to each segment of the display area corresponding to the change in the measured event for all display segments 5 is shown in FIG. 3(b) and (C) in chronological order.
1. The effective voltage to each display block A, B, and C is controlled by cyclically applying an application pattern of dl.

Display segment 5 with electrodes formed on TN type liquid crystal cell 6
The third display area corresponds to the traveling speed by applying a voltage to
Assume that it is stable at the level shown in Figure (a). In other words, assuming that the traveling speed is constant and the display area based on this is also fixed at a certain value, Fig. 3 (b+, (C1, (dxi
A specific voltage waveform that provides the application pattern shown in FIG. 4 will be explained as follows.

The voltage applied to the common electrode facing each segment/ent in display segment 5 is Y, and the voltage applied to the segment electrode corresponding to display block A that lights up the brightest is XA.
, if the voltage applied to the segment electrode corresponding to display block B to be lit second brightly is XB, and the voltage applied to the segment electrode corresponding to display block C to be lit third brightest to be XC, then each display block A , B, and C, the waveforms of the interelectrode voltages XA-Y, XB-Y, and XC-Y are as shown in FIG. That is, by shifting the phase of the segment electrode signals XA, The effective voltage of the LED is set, and lighting display is performed in which the luminance varies stepwise with transmittance according to the characteristics shown in FIG. Here, the application patterns shown in FIG. 3(b), (cl, and (d)) are set at equal time intervals, and if the time distribution of each application pattern is t+, t2.t3, at time L+, Interelectrode voltages XA-Y, XB-Y, Control is performed using a cycle of an application pattern in which XA-Y and XB-Y are in an applied state, and furthermore, at time t3, only the interelectrode voltage XA-Y corresponding to display block A is in an applied state. Between the electrodes corresponding to each display block A, B, C is shown in FIG. 4e.

Display signals as shown in f and g are applied, and the liquid crystal cell 6 is driven with a light transmittance corresponding to each effective voltage, resulting in an analog display with luminance changes as shown in Fig. 3 (al). It is something that

The above is an example of a liquid crystal driving method that provides a display pattern (hereinafter referred to as gradation display) as shown in FIG. 3(a) with a stepwise change in luminance when the traveling speed is constant and the display area is fixed. FIG. 5 shows a circuit configuration diagram for applying such a drive signal and specifically displaying the running speed of the automobile in gradations in a similar display pattern.

First, the main structure of the display device according to the present invention is a detection section S that converts a change in a measured event into an amount of electrical change, and a bar graph display based on measurement data from the detection section S. A lighting control circuit T that generates and outputs a control signal, and a display section that includes a bar graph display section in which a plurality of display segments are arranged and that can vary the amount of optical change depending on the control signal from the lighting control circuit T. explained.

The specific circuit configuration of each part uses a liquid crystal cell with the characteristics shown in Figure 2 as a display element, and Figures 3(b), (cl, (d))
An example of obtaining the display signal shown in FIG. 4 based on the cyclic application pattern control shown in FIG. 4 will be described in detail below. Needless to say, the specific configuration of each part differs depending on the type of device.

The configuration for obtaining gradation display based on FIGS. 2 to 4 will be described below.

The speed detection circuit 7, which generates a repetitive S) signal with a frequency proportional to the running speed of the vehicle, is composed of an electromagnetic pickup and a waveform shaping device that outputs an alternating current signal by facing a gear gear interlocking with an axle and changing its magnetic permeability, for example. Consists of circuits, etc. Output pulses from the speed detection circuit 7 are input to a counter 8 that counts at a predetermined gate time, and are transferred to a converter 9 as speed data corresponding to the traveling speed. The converter 9 outputs display area data indicating the number of display area segments corresponding to the traveling speed for all display segments of the display, which will be described later. The pattern generator 10 sets, based on the output data from the converter 9, how many levels of display blocks the display area is to be divided into, and furthermore, how many display segments each display block should be formed with. The required display signal application patterns as shown in FIGS. 3(b), (cl, and (d)) are determined and a display pattern command is output to the data generator 11. The number of segments in the block is converted by 9
The configuration may be such that the display pattern is selected from among several display patterns set in advance depending on the size of the display area data from , or the configuration may be configured such that each segment is one display block. The following description assumes that a three-level gradation display as shown in FIG. Based on the display pattern command from the pattern generator 10, the data generator 11 shown in FIG.
Display data as an application pattern as shown in (d) is generated and output to the liquid crystal drive circuit 12. The display 13 is equipped with a liquid crystal display device in which display segments are arranged to obtain an analog display as shown in FIG. 3 (al).Specifically, as shown in FIG. A TN type liquid crystal cell 15 is provided in which electrodes and a common electrode facing each other are formed on the inner surfaces of two transparent substrates.
Polarizers with polarization axes parallel to each other are attached to both sides, a semi-transparent color reflector 16 is arranged behind the polarizer, and a light source lamp 17 for transmitted illumination is provided behind the polarizer. A cutout window 18 is formed on the front side so that only the above-mentioned pargraph display section 14 can be seen through, and a display plate 19 with scales or numbers printed thereon for reading the running speed is arranged. By applying a voltage between predetermined electrodes forming the display portion 14, the portion becomes transparent, and the color of the illumination that passes through the semi-transparent color reflector 16 stands out and becomes visible.

20 is determined in the pattern generator 10 in FIG.
b), (C1, a timer circuit for controlling the time to cyclically output the application pattern as shown in (d) to the data generator 11 at predetermined time intervals; 21 is a counter that manually updates the counting contents using the output pulses from the timer circuit 20 and cyclically outputs the counting contents with an update number corresponding to the number of application patterns.
The application pattern output from 0 is determined according to the content of this count.

Further, the time interval of output pulses from the timer circuit 20 is determined based on the count contents of the counter 21. In other words, the output time of the application pattern based on the count contents of the counter 21 generated by the pattern generator 10 is determined by the output pulse time interval from the timer circuit 20 corresponding to the same count contents. ing. Here, the counter 21 in this embodiment, which obtains a three-level gradation display by three application patterns, has a counting content of (0, 1
, '2) is configured to be reset by the carry signal so that it is repeated in three types. 22 is a common signal generation circuit for obtaining a common electrode signal as shown in FIG. The configuration is such that the output is inverted by setting the generation cycle of display data.

Here, a pattern generator 10 that determines an application pattern based on the force and the count contents of the counter 21;
A mutual display pattern generator in the data generator 11 that generates and outputs display data for driving the display device 13 based on a display pattern command from the data generator 11.

Explain the work.

Now, the application patterns corresponding to the count contents (0, 1, 2) of the counter 21 are shown in FIG. 3 (bl, (cl, (d)
1, the pattern generator 1o first generates a display segment at the tip of the display area at a scale position corresponding to the traveling speed based on the display area data from the converter 9 in accordance with the update of the counting contents of the counter 21. Output the number of display segments corresponding to display blocks A, B, and C, that is, the data of the number of all display segments in the display area, and then output the display segments corresponding to display blocks A, B from the display area and the most advanced display segment. The function is to output data for the number of display segments, further output data for the number of display segments corresponding to the display block A from the most advanced display segment in the display area, and give the repetition data of this application pattern to the data generator 11 as a display pattern command. to do.

Based on the output data from the pattern generator 10, the data generator 11 generates display data for directly driving the display segments of the display 13 from the data corresponding to each display segment (all display segments) via the liquid crystal drive circuit 12. generate. Specifically, the liquid crystal drive circuit 12 includes a number of shift registers corresponding to the total number of segments, a launch circuit that latches the contents of all registers as parallel data, and an exclusive OR of the output of each latch circuit and a signal to a common electrode. For those having an output, it is proposed to serially input display data from a data generator 11 having a built-in clock generator. That is, when driving display segments corresponding to display block A as shown in FIG. Set the output data condition to (shift register of data input section) to 0,
Output data 0 is input to the shift register by a clock signal from the clock generator by N-n, which is obtained by subtracting the number n of segments corresponding to the display area based on the display area data from the total number N of display segments. The contents of the shift register shifted by N-n are now shifted by N-n from the input side.
The number of pieces is kept as 0. Next, with the output data condition set to 1, the number of segments to be driven, nA, is input to the shift register at a clock signal cycle, and the contents of the register for nA segments from the input side are set to 1. Therefore, the N-n 0 data that had been input and held before this time is sequentially shifted to the upper side by nA, and the register contents at this time are n from the input side.
A piece is 1. From there, N-n pieces are held in 0-to-taha turns. Next, the output data condition is set to 0 again, and the remaining number of segments in the display area, that is, n-nA, is input to the shift register at a clock signal period, and n
-nA register contents are set to 0. At this time as well, the register contents that were previously input and held are sequentially shifted to the upper side, and when the above n-nA 0 data input is completed, display data corresponding to the total number of display segments N is formed. At the same time as this display data is formed, the data generator 1
The display data contained in the shift register is transferred and held in the latch circuit by the latch signal outputted from the shift register 1, and the generation of the display data that provides the application pattern as shown in FIG. 3 (dl) is completed.

The generation of such display data is executed in the same process in the case of FIGS. This is done by updating the counting contents of the pattern generator 10.
The display pattern command is shown in FIG. 3(b).

(C1 and (d) are repeatedly output in this order, and the data generator 11 generates display data in sequence based on each output data.

In this case, t shown in FIG. 3(b), (c), and (d)
The application pattern output at time intervals of 1, t2 and t3 is regarded as one cycle, and the common electrode signal data from the common signal generation circuit 22 is inverted to provide an output pattern corresponding to FIG. The latch circuit output as display data is also inverted every cycle by the exclusive OR output, as shown in FIG. 4, c.

It is supplied as segment electrode signal data of the output pattern corresponding to d, and the liquid crystal drive circuit 12 is driven based on each electrode signal data.

In the liquid crystal drive circuit 12, the liquid crystal cell 1 of the display 13 is controlled based on the display data generated by the data generator 11.
The display signal shown in FIG. 4 for driving 5 is formed and output, and the generation cycle of the display data is as shown in FIG. 3(b).
, (tl giving the application pattern of (C1, (d)),,
The time distribution is set as tq and t3. The pergraph display section 1 of the liquid crystal cell 15 provided in the result display 13
The voltage applied to the four segment number poles is 4 for each display segment corresponding to display blocks A, B, and C shown in FIG.
As shown in Figures 4c and d, the signals to the common electrode (Figure 4a)
), but are supplied as waveforms with a phase shift of t+, t2° and t3, respectively. Therefore, display blocks A, B (
The voltage between the opposing electrodes corresponding to c is given as e + f + g in Figure 4, and the effective voltages to the display parts in each program are applied at a ratio of substantially 3:2:1,
The liquid crystal cell 15 is driven with transmittance corresponding to each. In this case, Fig. 3 (bl, (C1, (d)
Since the time interval of the application pattern shown in is set according to the relationship t+=t:z=ts, when using a liquid crystal having the applied voltage-light transmittance characteristics shown in FIG.
As shown in C, when display block A has a light transmittance of 100%, display block B has a light transmittance of 50%.

The display block C is displayed in three levels of gradation at a rate of approximately 0%. Here, display block C provides a display in which most of the display is in a non-lit state, but display block A is also set in a lit state.

If you want to obtain a display with different lighting brightness from B, you can adjust the settings of the time intervals tl, tco, and t3 of the application pattern shown in Figure 3 (bl, (C1, (dl) as appropriate, or change the applied voltage. - This can be achieved by using a liquid crystal that has a large linear light transmittance characteristic and a wide control range.

When displaying the ratio of l, the light transmittances of A, B", and C' in the figure can be obtained, and it is sufficient to apply an applied voltage such that the specific gravity of the applied voltage to obtain this light transmittance ratio is the same characteristic It is sufficient to perform time control to provide the conditions of VA:VB':VC'' required from the leather. Specifically, the third
Figures (b), (C), (ratio of time intervals tl, t!, t3 giving the application pattern of dl, that is, the data generator 1
The generation period of display data in 1 is determined by t+ +l corresponding to the applied voltage (effective value) ratio VA:■B':Vc'
+ta: t+ +txQin) H# completed 1' peak meeting *:
1+ iI name ψ Children's food can be easily displayed by setting the ratio that satisfies the red color.

It is possible to set the ratio of lighting brightness of C.

Next, the above display control will be explained as follows for the speedometer of this embodiment.

If the vehicle is currently in a stopped state, no output pulse is generated from the speed detection circuit 7, and therefore the content of the counter 8 is 0. Therefore, the display area data from the converter 9 is also output as O to the pattern generator 10. The pattern generator 10 provides a display pattern command to the data generator 11 based on the display area data. The data generator 11 generates an override that controls the liquid crystal drive circuit 12 based on this display pattern command, but in this case, since the display data is O, which part of the liquid crystal cell 15 forms the entire part graph display section 14, No display signal is applied to the electrodes either.

Therefore, the pergraph display section 14 maintains a non-transparent state in its entire area as shown in FIG. 7(a), and displays that the traveling speed is O. In this case, a method is also proposed in which only the lowest display segment is in a transparent state and replaced with O display.
In order to obtain such a display, the converter 9 may provide the pattern generator 10 with display area data that always drives one segment even if the content of the counter 8 is 0.

Next, when the speed detector 7 outputs a pulse signal with a frequency proportional to the running speed as the car runs, the counter 8 counts this pulse signal at a predetermined gate time period. The count contents are converted by the converter 9 into display area data consisting of the number of segments corresponding to the display area according to the speed, and then sent to the pattern generator 10.
will be forwarded to. Now the pergraph display section 1 of the liquid crystal cell 15
The total number of display segments forming 4 is 80, the display unit of each segment is 2 km/h, and the maximum indicated speed is 1.
If set to 60km/h, the display area data output from the converter 9 for a traveling speed of 40km/h will be "
20". Furthermore, if the number of luminance change segments in the display area in three stages is fixed as "6", the pattern generator 10 will use the settings as shown in FIG. 3(b), (C1°(d
) cyclically outputs a display pattern command for giving the application pattern shown in FIG. That is, based on the display area data "20" from the converter 9, data "20" corresponding to the total number of segments in the display area is first outputted to the data generator 11 as the first application pattern. Next, the segment number setting values r2J and r6J for the display blocks A and B are set.
Based on this, data "8" corresponding to the number of segments in display block A and B areas is output as a second application pattern, and then data "2" corresponding to display block A area is output as a third application pattern. do. The conditions for generating the application pattern at this time are determined by the count contents of the counter 21 that counts the signal output from the timer circuit 20, but the conditions in this case are the contents (0, 1,
r20J corresponding to 2).

It is set so that data of r8J and r2J is output. In addition, here, the number of segments for display blocks A and H is fixed as r2J and r6J, respectively, so it is not necessary to use display area data as one generation condition, but depending on the size of the display area that increases or decreases depending on the traveling speed. When changing the number of display blocks or the number of segments for each display block, set multiple numbers of segments for each display splitter, and select one number of segments based on the display area data. This data is necessary as a display pattern generation condition.

The display pattern command generated in the pattern generator 10 in this way is transferred to the data generator 11, and the data generator 11 generates a
Generating display data that provides a display signal to a predetermined segment corresponding to the content application pattern of all display segments of the book;
The liquid crystal cell 15 is driven through the liquid crystal drive circuit 12.

That is, as shown in FIG. 31(b), (cl, and (d)), in the first application pattern, 20
A display signal to the book segment is output, a display signal to eight segments corresponding to display blocks A and H is output in the second application pattern, and a display signal to eight segments corresponding to display block A is output in the third application pattern. The display signals to the two segments are output, and as a result, the effective voltage changes to the segments corresponding to each display block A, B, and C due to the cyclic output control of these display signals are shown in Figure 7 (three steps as shown in bl). This produces a gradation display with a luminance change of .

Therefore, the driver can reliably decipher changes in driving speed using the pergraph display, which uses the brightest display block A as the indication tip and gradually decreases in brightness, and among the display patterns that also indicate the upward direction of the display area. This can be visually recognized as a smoother change. In addition, unlike the display based on the area ratio of bright and dark areas, by providing a gradation display based on stepwise changes in luminance, the luxury required for electronic displays is enhanced, making the display device suitable as an analog display with high visual recognition effects. This is something that can be provided.

Note that FIG. 7(C) shows an example of a display pattern in which an applied voltage is applied to give a slight transmittance of θ to segments other than the display area for instructing the running speed, and the bar graph display section 14 is dimly lit in advance. The structure is such that a gradation display with a higher luminance display area change is provided.

In addition, in the embodiments detailed above, the display area corresponding to changes in the measured event is displayed as a bright display, and a gradation display is shown in which the brightness gradually decreases from the display block at the tip of the indicator. It is also possible to obtain a gradation display in which the display area is darkened based on the bar graph display section. This can be easily achieved by changing the liquid crystal cell 15 in the display 13 shown in FIG. 6 to a positive display type. That is, the liquid crystal cell L/15 in the above embodiment is arranged so that the polarization axes of the polarizers attached to both sides are parallel to each other,
Although the configuration is normally in a non-transparent state, by arranging the polarization axes of the polarizers so that they are perpendicular to each other, it is possible to obtain a configuration in which the polarizers are normally in a transparent state and become non-transparent when a voltage is applied. Thus, a gradation display as shown in FIG. 7(d), in which the bright and dark display portions are inverted with respect to the above embodiment, can be obtained. In this case, the brightness change in the display area is given by a combination of display blocks B and C that gradually become brighter from the darkest display block A, and the lighting control circuit T is also applied with exactly the same configuration as in the above embodiment. obtain.

Furthermore, the above-mentioned gradation display was explained using the example of the display range increasing in one direction from the lower part to the upper part of the bar graph display area, but the gradation display area increases in both left and right directions from the center as shown in Fig. 1(b). It can also be applied to expanding display patterns, and the gradation display when the display area is set to bright display is shown in Figure 7 (
81.

The lighting control circuit T in this case can also be constructed by a combination corresponding to the embodiment shown in FIG. In other words, the liquid crystal drive circuit 12
By connecting the display segments positioned symmetrically in the left and right directions of the par graph display section 14 as a pair, and applying the same display signal as in FIG. It is possible to obtain a gradation display that becomes a display pattern.

Further, FIG. 7(f) shows a gradation display in which a circular bar graph display section 14 is formed by display segments arranged in a fan shape, and changes in brightness of the display area are given by a display block configuration of one segment at a time. There is. Brightness control in this case can be achieved by setting conditions to increase the number of display blocks using a similar drive circuit that changes the effective voltage applied to the segments of each display block as shown in Figure 5, but optical It is desirable to use a display element whose characteristics allow the change (light transmittance in the case of liquid crystal) to be controlled over a wide voltage range.

Furthermore, although the above-mentioned embodiment shows an example of a lighting control circuit that uses a liquid crystal cell as a display element and controls its light transmittance, a display segment such as a light emitting diode or a fluorescent display tube is used as a display element. A self-luminous element may be used which can vary the brightness by controlling the effective voltage of the display signal. The luminance brightness of such self-luminous elements can be controlled by changing the duty ratio of the display signal to the display segment as a pulse signal or by using a DC driver.
The brightness control method can be easily configured by dynamic driving, including a method of changing the applied voltage level and a liquid crystal cell.

In any case, it is necessary to decide how many display blocks the display area should be divided into depending on changes in the measured event, and how many segments each display block should have, and display signals to each display block should be determined. The configuration of the lighting control circuit T for outputting (deity ratio control or DC voltage control) can be designed as appropriate by selecting the display element or display pattern, and a suitable mode may be selected depending on the application. .

As described above, the present invention arranges a plurality of display segments to form a pergraph display section, and displays optical changes in the display area by selectively applying voltage according to changes in the measured event. The display area, which increases or decreases in response to changes in the measured event, is divided into display blocks each consisting of a predetermined number of segments, and the amount of optical change is determined by controlling the voltage application to the segments corresponding to each display block. By changing the display in stages, it is possible to provide analog and log displays with good visibility, and furthermore, by indicating changes in the measured event as gradation displays with varying brightness in stages. The upward direction of the area can also be read at a glance, and it is possible to provide a bar graph display device that is luxurious in appearance, has excellent reading performance, and has high commercial value.

[Brief explanation of the drawing]

FIG. 1 is a front view illustrating a display pattern in a conventional pargraph display device. FIG. 2 is a characteristic diagram showing the relationship between applied voltage and light transmittance of a liquid crystal cell adopted as an example for suppressing changes in lighting brightness according to the present invention. FIG. 3 is an explanatory diagram showing an example of a display segment drive signal application pattern for obtaining luminance changes according to the present invention. FIG. 4 is a voltage waveform diagram for driving a liquid crystal cell having the characteristics shown in FIG. 2 based on the application pattern shown in FIG. FIG. 5 is a circuit configuration diagram showing an embodiment of the display device of the present invention for displaying the running speed of an automobile in a bar graph using a liquid crystal cell having the characteristics shown in FIG. 2 and the driving waveform shown in FIG. 4. FIG. FIG. 6 is a perspective view of a liquid crystal cell as a display element configured as a speed type of the embodiment of FIG. FIG. 7 is a front view illustrating the display pattern of the bar graph type speedometer using the liquid crystal cell shown in FIG. 7: Speed detection circuit 8: Counter 9: Converter 10: Pattern generator 11: Data generator 12: Liquid crystal drive circuit 13: Display device
14: Bar graph display section 15: Liquid crystal cell 20
:Timer circuit 21: Counter 22: Common signal generation circuit! - 2nd WIJ Inatsu 1115-<ri No. 8 helmet (C No. 6-〇-1□ 171f cf)

Claims (1)

[Claims] A bar graph display device in which a change in an event to be measured is indicated by a plurality of aligned display segments that are selectively displayed according to the change. a display section capable of controlling the amount of optical change thereof by selectively applying a voltage to the segments; and a display section that determines a display area in a display segment row of the display section according to a change in the measured event, and sets the display area to a predetermined value. A display device comprising a lighting control circuit that controls voltage application to each segment so that the amount of optical change differs for each of a plurality of display blocks each having a number of segments.