JPH02165189A - On-vehicle liquid crystal display device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an in-vehicle liquid crystal display device, and in particular an in-vehicle liquid crystal display device that can change brightness and display color depending on the brightness of the external environment and the driving condition of the vehicle. The present invention relates to a liquid crystal display device.

(Prior Art) An example of a conventional vehicle-mounted liquid crystal display device is one described in, for example, Japanese Utility Model Application No. 61-59141.

The conventional device described in this publication is used in instruments of a vehicle and includes a discharge lamp and an incandescent light bulb as a light source for transmitted illumination of a liquid crystal display device. And when driving during the day,
The discharge lamp is turned on to illuminate the liquid crystal display device with high brightness, while when driving at night, the switching circuit is activated to turn off the discharge lamp and turn on the incandescent light bulb in synchronization with the turning on of the headlights. As a result, the liquid crystal display device is illuminated with a low-intensity incandescent bulb.

According to this conventional device, since the liquid crystal display device is illuminated by a high-intensity discharge lamp during the day, the indication data of the instruments can be viewed clearly even in a bright external environment. On the other hand, at night, the lights are illuminated with low-brightness incandescent bulbs, so even if the outside environment is dark, the indication data on the instruments can be seen clearly without glare.

(Problem to be Solved by the Invention) However, in the above-mentioned conventional technology, since an incandescent bulb is attached to a lighting device using a discharge lamp, when only the incandescent bulb is turned on for night illumination, the discharge that is in the off state There are cases where the lamp obstructs illumination, making it difficult to provide uniform illumination over the entire display area.

An object of the present invention is to eliminate the problems of the conventional device by using only a discharge lamp that can produce white light with high brightness and good color rendering as a light source for backlighting, and to
To provide a liquid crystal display device capable of displaying at high brightness that provides sufficient visibility and at night at optimal brightness while suppressing glare.

Another object of the present invention is to be able to change the display color depending on day or night or in response to other conditions, display at high brightness for sufficient visibility during the day, and suppress glare at night. An object of the present invention is to provide a liquid crystal display device capable of displaying images with optimum brightness.

(Means for Solving the Problem) The invention of claim (1) provides that the liquid crystal display element segment electrodes of a liquid crystal display device are formed into two or more sets of alternating stripes that are independently controlled, and any set of stripes may be formed into an arbitrary set of stripes. A feature of the vehicle is that it has a means to turn off the display using the electrodes at the same time as the discharge lamp that is the backlighting light source is dimmed by closing the lighting switch for headlights and other illumination lights for night driving. .

The invention as claimed in claim (3) provides a means for extinguishing the display by the arbitrary set of striped electrode parts when the magnitude of the vehicle speed exceeds a predetermined value, and a means provided opposite to the striped electrode parts. The feature is that it is equipped with a filter.

(Function) According to the invention of claim (1), the liquid crystal display illuminated by the discharge lamp is sufficiently bright and has good visibility during the day.

On the other hand, when driving at night, the light of the discharge lamp itself is reduced by closing the lighting switch, and the transmittance of the liquid crystal display is reduced by turning off one of two or more sets of alternating striped electrodes that constitute each display segment. It is possible to obtain a display with moderate brightness without glare.

Further, according to the invention of claim (3), the display can be displayed brightly during the day and bright enough to avoid glare at night, and when the vehicle speed exceeds a scheduled value, the speedometer can be displayed in red, for example. It is possible to use color to warn the driver of excessive vehicle speed.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a system schematic diagram of an in-vehicle liquid crystal display device of the present invention. The liquid crystal display element 1 has segment electrodes 1a and lb, which are two sets of fine striped transparent electrodes, which are alternately formed under a transparent substrate le. Further, a liquid crystal substance 1d is filled on the lower side of the transparent substrate 1e, and a common electrode I opposite to the segment electrodes 1a and lb is below the liquid crystal substance 1d.
A transparent substrate 1f on which C is formed is provided. Also,
Polarizing plates Ig, l are provided on the outside of the upper and lower transparent substrates 1e, if.
h are arranged respectively.

A plan view of an example of the liquid crystal display element 1 is shown in FIG. In the illustrated example, the display segments rlJ, r8J, and r8J are all composed of the two segment electrodes 1a and 1b. , will be explained in detail. In FIG. 3, display segment "8" consists of seven segments a-g,
Each segment is composed of two segment electrodes. For example, segment a is segment electrode 13aR.
and 13aG, and segment b is composed of segment electrodes 13bR and 13bG. Similarly,
Segment g is composed of segment electrodes 13gR and 13aG.

Also, a common electrode 1 is provided opposite each segment a-H.
3 is provided, and the common lead wire 12 is connected to the common electrode 13.
is connected. Although not shown, it goes without saying that liquid crystal is filled between the segment electrodes a to g and the common electrode 13.

As is clear, the segment electrode 13aR.

13bR, . . . , 13gR correspond to the segment electrodes 1a (or lb) in FIG.
aG, 13 bG, -z 13 gG correspond to segment electrode 1b (or la) in FIG. Also,
The common electrode 13 corresponds to the common electrode IC shown in FIG.

FIG. 4 is a diagram showing another example of the liquid crystal display element 1.

In this example, segment electrodes 10a and fib common to the digits are provided, and electrodes (9a, 9b, etc.) that can be independently controlled are provided facing each segment of each digit.

, in the example of FIG. 4, the segment electrodes 10a+10b
are the segment electrodes 1a, lb (or 1b, 1a) in FIG.
), and the electrodes 9a, 9b, etc. correspond to the common electrode I in FIG.
It corresponds to C.

The explanation will be given by returning to FIG. 1 again.

As is clear from the above description, all display segments are composed of fine stripes, and the segment electrodes 1a
and 1b are drawn out so that they can be independently controlled by the control circuit 5.

The display illumination discharge lamp 2 is controlled by a lamp drive circuit 3, and a lighting switch 4 and a dimming signal input terminal 6 for a headlamp for night driving are connected to the lamp drive circuit 3.

The signal from the lighting switch 4 is also input to the control circuit 5.

The dimming signal input terminal 6 has a duty of 20% from DC.
It is possible to selectively apply a rectangular wave up to a certain degree.

FIG. 5 shows a signal applied to the dimming signal input terminal 6 when the lighting switch 4 is off and when the lighting switch 4 is turned on.
2 shows how the brightness of the discharge lamp 2 changes when changing from 0% to 20% duty to a rectangular wave. In this figure, the brightness of the discharge lamp 2 when the lighting switch 4 is off is 100% brightness.

As is clear from the figure, while the lighting switch 4 is off, the discharge lamp 2 emits light at 100% brightness. Further, when the lighting switch 4 is turned on and a dimming signal with a duty of 100% is applied to the dimming signal input terminal 6 during parentheses, the brightness of the discharge lamp 2 becomes about 30%. Next, when the duty of the dimming signal is reduced from 100% to 20%, the brightness of the discharge lamp gradually decreases, and when the duty reaches 20%, the brightness of the discharge lamp 2 is approximately It becomes 10%.

The control circuit 5 in FIG. 1 has a drive signal application terminal 5a.

Data signal generation units 5b, 5c, exclusive OR game) 5d
, 5e. A continuous rectangular wave signal with a duty of 50%, for example, is applied to the drive signal application terminal 5a, and the data signal generators 5b and 5c are set to H (high) level when making the corresponding segment brighter, and L when making it darker. Outputs a (low) level signal. Furthermore, when the lighting switch 4 is turned on, the data signal generating section 5c forcibly outputs an L level signal.

Assuming that the lighting switch 4 is now off, that is, open, the discharge lamp 2 is turned on by the lamp drive circuit 3, illuminating the liquid crystal display element 1 with high brightness. At this time, assuming that H level signals are being output from the data signal generating sections 5b and 5c, the segment electrodes 1a of the liquid crystal display element 1.

A voltage opposite to that of the common electrode IC is applied to 1b, and a voltage is applied between the common NMA1c and both segment electrodes 1a and 1"b, so that both the a region and b region are in the on state. Therefore, the light from the discharge lamp 2 passes through the segment electrodes 1a and 1b, and a high-intensity display with sufficient visibility even during the daytime is performed.

On the other hand, when the lighting switch 4 is turned on or closed during night driving, an H level signal is input to the lamp drive circuit 3.

When the H-level signal is input manually, the lamp drive circuit 3 dims the discharge lamp 2 to about 30% brightness when daytime brightness is 100%. Further, when the lighting switch 4 is turned on, the data signal generation section 5C outputs an L level signal. Dimming signal input terminal 6
For example, when a rectangular wave dimming signal with a duty of 20% is input, the lamp drive circuit 3 responds to the dimming signal and dims the luminance from about 30% to about 10%.

Now, if the lighting switch 4 is changed from off to on and a dimming signal with a duty of 20% is input to the dimming signal input terminal 5, the discharge lamp 2 will be turned on at 1 of the daytime brightness.
It changes so that it emits light at about 0% brightness. Further, the data signal generation section 5b continues to output an H level signal, but the data signal generation section 5C starts to output an L level signal. Therefore, exclusive OR gate 5
A voltage is applied between the segment electrode 1b connected to the gate d and the common electrode 10, and the light from the discharge lamp 2 passes through the segment electrode 1b, but the light from the segment electrode 1a connected to the exclusive OR gate 5e No voltage is applied between the common electrodes IC, and light from the discharge lamp 2 no longer passes through the segment electrodes 1b.

Now, suppose that the width of each of segment electrodes 1a and lb is a
, b, and each length is equal, the ratio of the area occupied by the segment electrodes 1a and lb is to a. Therefore, as mentioned above, the lighting switch 4
is changed from off to on, and a dimming signal is input from the dimming signal input terminal 6, the display brightness A of the liquid crystal display element 1 is as follows, where the daytime display brightness is Ao. Become.

A= lb/(a+b)) X (10/100) XA.

The widths of the segment electrodes 1a and lb are equal (a-b)
If the daytime display brightness AO is, for example, 100 (nits), the display brightness A during night driving can be reduced to 5 (nits).

In the above description, the 8th dimension and the 5th dimension are assumed to be the same, but it goes without saying that the ratio may be changed depending on the degree of light attenuation. Further, in the above embodiment, the display segment is composed of two sets of segment electrodes, but the display segment is not limited to two sets, but can be composed of three or more sets of segment electrodes, and when the lighting switch 4 is turned on, any set of segment electrodes can be set. The segment electrodes may not transmit light.

(Application example) If striped two-color color filters are provided inside or outside the liquid crystal tank in correspondence with the segment electrodes 1a and 1b of the liquid crystal display element 1, two-color additive color display can be performed during the day. At night, the display can be displayed in one of the display colors, and the display color can be easily switched between daytime and nighttime.

A second embodiment of the invention is shown in FIG. This embodiment is characterized in that the data signal generating section 5c is controlled by the output signal of the vehicle speed over detecting means 7.

For example, a green filter is provided in correspondence with the segment electrode 1a, a red filter is provided in correspondence with the segment electrode 1b, and vehicle speed data sent from a vehicle speed sensor etc.
For example, when the vehicle speed over detecting means 7 detects that the vehicle speed has exceeded 100 kll/hour, the data signal generating section 5c is forced to output an L level signal. It will be displayed in a mixed color of green and red when the speed exceeds 1100 k/hour. Therefore, according to the second embodiment, the driver can be informed by color display that the vehicle speed exceeds 1100 k/hour.

In addition, as another modification, the lighting switch 4
and the output of the vehicle speed over detection means 7.
), and the output of the logical sum is used as the data signal generator 5C.
may be controlled.

According to this modification, during the day the vehicle speed increases to 100+e
/ hour, the display color changes, and at night the display color changes when the time exceeds 1100k/hour.
It will be displayed in the color displayed when time is exceeded.

(Effect of the invention) According to the invention of claim (1), the lighting switch 4
The device is equipped with a discharge lamp whose light is dimmed when the LCD panel is closed, and a means to reduce the transmittance by controlling the aperture ratio of the display segment of the liquid crystal display element, allowing the liquid crystal display device to have a wide dimming range. , optimal brightness during day and night can be obtained with a single light source.

According to the invention of claim (2), since the liquid crystal display element is provided with striped color filters corresponding to the segment electrodes, the display color can be easily switched between day and night, improving visibility. effective.

According to the invention of claim (3), a discharge lamp whose light is dimmed when the lighting switch is closed, and a means for making a part of the display segment of the liquid crystal display element opaque when the vehicle speed exceeds a predetermined value are provided. Therefore, the brightness of the liquid crystal display element can be switched between day and night, and a warning can be issued to the driver using a display color when the vehicle speed exceeds a predetermined value.

[Brief explanation of the drawing]

FIG. 1 is a system schematic diagram of one embodiment of the liquid crystal display device of the present invention, and FIG. 2 is a plan view showing one specific example of the liquid crystal display element.
3 is a detailed plan view of the first specific example of the liquid crystal display element, FIG. 4 is a detailed plan view of the second specific example of the liquid crystal display element, and FIG.
The figure shows the relationship between the brightness of the discharge lamp, the on/off of the lighting switch, and the duty of the dimming signal.
FIG. 6 is a system schematic diagram of another embodiment of the present invention. Fig. 1...Liquid crystal display element, la...segment electrode. 1b...Segment electrode, 2...Discharge lamp, 3.
... Lamp drive circuit, 4... Lighting switch. 5... Control circuit, 5b, 5c... Data signal generation section. 6... Dimming signal input terminal, 7... Vehicle speed over detection means agent Patent attorney Michito Hiraki and 1 other person

Claims (3)

[Claims] (1) In a liquid crystal display element formed by filling a gap between a transparent substrate having a common electrode and a transparent substrate having segment electrodes with liquid crystal, and a liquid crystal display device using a discharge lamp as a light source for back illumination, the segment electrodes are , two or more sets of fine alternating stripes are controlled independently, and the display by the stripe-like electrode portions of some of the sets is turned off in conjunction with a dimming lighting switch of the discharge lamp. An in-vehicle liquid crystal display device featuring: (2) The liquid crystal display element is a color liquid crystal display element provided with striped color filters of at least two colors corresponding to the two or more sets of fine alternating striped segment electrodes. An in-vehicle liquid crystal display device according to claim (1). (3) In a liquid crystal display element formed by filling a gap between a transparent substrate having a common electrode and a transparent substrate having segment electrodes with liquid crystal, and a liquid crystal display device using a discharge lamp as a light source for back illumination, the segment electrodes are , two or more sets of fine alternating stripes are controlled independently, and the display by the stripe-like electrode portions of some of the sets is turned off depending on the vehicle speed, and the discharge lamp is dimmed by a dimming lighting switch. An in-vehicle liquid crystal display device characterized by: