JP4165438B2 - Liquid crystal display - Google Patents

Description

  The present invention relates to a liquid crystal display device that includes a light transmittance adjustment panel such as a smoke lens on the front surface of a liquid crystal display to improve the appearance of display at the start and end of display.

Conventionally, in a liquid crystal display device equipped with a liquid crystal display and a backlight that makes light incident on the liquid crystal display from the back, at the start of display, the dimming level of the light output of the backlight is gradually increased to At the end, a technique is known in which the dimming level of the light output is gradually lowered to enhance the effect of the display unit (see, for example, Patent Document 1).
JP-A-10-74049

  However, since the liquid crystal display is a transmissive element rather than a natural light emitting element, if the backlight is turned on when the display is turned off, there is a possibility that the effect of the display portion and the appearance of the display unit may be affected by light leakage. is there.

  The present invention has been made in view of the above points, and provides a liquid crystal display device capable of improving the appearance of the display section at the start and end of display as well as the appearance of the display section when the display is turned off. The purpose is to do.

In order to achieve the above object, the technical means described in claims 1 to 3 are employed.

According to the first aspect of the present invention, a liquid crystal display, backlight means for making light incident on the liquid crystal display from the back, a light transmittance adjusting panel provided on the front of the liquid crystal display, and the liquid crystal display And a control means for controlling the operation of the backlight means, a light-emitting display image of the liquid crystal display is visually recognized through a light transmittance adjustment panel,
The control means is characterized in that at the end of display, the light control level of the light output of the backlight means is gradually lowered, and the display on the liquid crystal display is ended when the light control level becomes a predetermined level or less.

  As a result, when the display is off and the liquid crystal display is not in operation, the combination of the liquid crystal display and the light transmittance adjustment panel can effectively suppress light leakage and terminate the display operation. Sometimes the light output level of the backlight means is gradually lowered to the off level and then the display on the liquid crystal display is terminated, so that the display image disappears in a clear display image state. Such a production effect can be obtained, and the appearance of the display unit can be improved.

According to a second aspect of the present invention, in addition to the configuration of the first aspect, the control means starts the display of the liquid crystal display at the time of starting the display, and controls the dimming level of the light output of the backlight means. It is characterized by gradually increasing the value.

  Thereby, when the liquid crystal display is not operating when the display is turned off, the light leakage can be effectively suppressed by the combination of the liquid crystal display and the light transmittance adjusting panel. Moreover, at the start of the display operation, first, the liquid crystal display is turned on to stabilize the liquid crystal device, and the dimming level of the light output of the backlight means is gradually increased, so the backlight means is activated. The outer shape of the liquid crystal display does not rise strongly at the moment, and it is possible to improve the appearance of the display section by providing a presentation effect that the display image gradually rises from a dark place. Become.

According to the third aspect of the present invention, the control means receives the ON switch-on signal of the power switch, the liquid crystal display control means for starting the display operation of the liquid crystal display, and the backlight when receiving the ON switch-on signal Backlight control means for gradually increasing the dimming level of the light output of the means, and the same effect as in claim 2 can be obtained.

  An embodiment of the present invention will be described with reference to the drawings.

  The present invention is applicable not only to a vehicle but also to a display device for other purposes. Here, like an optitron meter of an automotive instrument, the contents of a display panel and the like are not visible when the power is turned off. Therefore, an example in which the internal modeling of the display unit is applied to a liquid crystal display device that is intentionally unknown by a smoke lens that is a light transmittance adjustment panel will be described.

  FIG. 1 is a front view of a combination meter 1 according to the present invention, and FIG. 2 is a cross-sectional view taken along line II in FIG.

  1 and 2, a combination meter 1 is arranged in an instrument panel in front of a driver's seat of an automobile and displays various vehicle information. For example, in a resin case 10, detection information (engine rotation) Number, vehicle speed), a liquid crystal display 40 that displays various warning information in the car as pictographs, a front panel 50 including a smoke lens that is a light transmittance adjustment panel, and a display panel 60. A printed circuit board 70 and a control device 80 for controlling the devices 20, 30, 40 and the like are housed.

  The pointer meters 20 and 30 include pointers 21 and 31 that can individually control light emission, and a movement 22 that rotates the pointer 21 via a shaft 23 (however, the movement of the meter 30 is not shown), and the control device 80 In response to the control signal, the pointers 21 and 31 are individually illuminated and displayed, or the dials 20a and 30a of the pointer meters 20 and 30 formed integrally with the display panel 60 and the outer frames 20b and 30b thereof are individually (independently). It is configured so that it can emit light.

  Thereby, at the start of the display immediately after turning on the ignition switch, only the hands 21 and 31 are displayed first, then the outer frames 20b and 30b are additionally displayed, and then the dials 20a and 30a are additionally displayed. Finally, the entire display panel 60 can be displayed. At this time, since the front panel 50 made of a smoke lens is provided, the inside is not visible. For example, the pointers 21 and 31, the outer frames 20 b and 30 b, and characters emerge as a light emitting display image sequentially from the black panel 50. It is displayed to rise. The control device 80 and the movement 22 are mounted on the printed circuit board 70.

  The liquid crystal display 40 corresponds to a liquid crystal panel 41 made of, for example, a TFT type liquid crystal device. The backlight 42 allows light to enter the liquid crystal panel 41 (liquid crystal display 40) from the back side, and includes, for example, a white light emitting diode and a light guide plate that guides the white light to the back side (back side) of the liquid crystal panel 41. Both 41 and 42 are controlled by the control device 80. Of course, if the liquid crystal panel 41 is for color display, color display is performed with various colors of light control levels corresponding to the light output of the backlight 42.

  The various warning information displayed is, for example, door opening or half-door information, transmission overdrive stage on / off information, battery charging status, remaining fuel shortage status, headlamp remote lighting status, engine oil level reduction information, etc. The items that should be warned are displayed in color, blinking, or enlarged.

  The smoke lens constituting the front panel 50 is made of a transmissive material, such as a thin plate-like polycarbonate resin, and has a light transmittance set to a predetermined value (for example, 20%) by coloring or the like. As a result, the display contents (light-emitting display images) displayed by the pointer meters 20 and 30 and the liquid crystal display 40 are visually recognized by the driver, but the main body of the meters 20 to 40 and the surrounding components are visible to the driver. Not visible. On the other hand, when the meters 20 to 40 are not lit and displayed, none of them are visually recognized by the driver, for example, a colored state determined by the smoke lens 50 such as a black system.

  Next, the control apparatus 80 is demonstrated based on FIGS.

  FIG. 3 is a block diagram illustrating a schematic configuration of the control device 80. The control circuit 81 includes a microcomputer including a CPU, a ROM, and a RAM, and includes a pointer control unit 811, a liquid crystal display control unit 812, and a backlight control unit 813 as function realizing units. In addition, it has drive circuits 82 and 84 that drive the devices 20, 30, 41, and 42 and a video circuit 83 upon receiving a control signal from the control circuit 81.

  The information input means 90 obtains information for controlling each device 20, 30, 41, 42 (information for a pointer instrument, information for liquid crystal display, panel illuminance information, etc.) from each part of the automobile, and a control circuit 81. In addition, the battery voltage + B is always supplied to the control device 80 without passing through the ignition switch 100, and an ON / OFF signal of the ignition switch 100 is input.

  Here, the pointer control means 811 of the control circuit 81 calculates the turning positions of the pointers of the pointer meters 20 and 30 based on the engine speed information and the vehicle speed information obtained from the information input means 90, and passes through the drive circuit 82. Then, the movement 22 is driven. In addition, the pointers of the pointer instruments 20 and 30 and the dials 20a and 30a and the outer frames 20b and 30b thereof are displayed in a light-emitting manner according to predetermined rules.

  The liquid crystal display control means 812 provides the display item information selected based on the various liquid crystal display information obtained from the information input means 90 to the video circuit 83. The video circuit 83 drives each liquid crystal cell of the liquid crystal panel 41 to display pictograms indicating display items selected by the liquid crystal display control means 812 on the liquid crystal panel 41 according to a predetermined rule.

  The backlight control means 813 controls on / off of the backlight 42 and the light output level when the backlight is on based on the on / off information of the ignition switch 100 and the illuminance information around the meter panel, etc. The display brightness of the (liquid crystal display 40) is adjusted (dimming).

  Specifically, the backlight control unit 813 outputs a signal (PWM signal) having a duty ratio corresponding to a target dimming level determined according to the illuminance around the meter panel, and the drive circuit 84 is configured to output each signal of the backlight 42. The light output is dimmed by turning on and off the light emitting diode at the duty ratio.

(Operation)
Next, a schematic operation of the control device 80 will be described with reference to FIG. FIG. 4 is a flowchart showing the outline control contents of the control device 80.

  Since the battery voltage + B is always supplied, the control device 80 is basically always operating. When the vehicle is in use, the pointer control means 811, the liquid crystal display control means 812, and the backlight control means 813 are operated. Let However, when the ignition switch 100 is in the OFF state, the operation content is limited to a minimum, and the front panel 50 is at a level at which the user cannot visually recognize at least the pointer meters 20 and 30 and the liquid crystal panel 41 (liquid crystal display 40). The light transmittance is set.

  While the automobile is in use by turning on the ignition switch 100, steps 201 to 206 shown in FIG. 4 are performed. First, when various information (information for pointer instrument, information for liquid crystal display, panel illuminance information, etc.) for controlling each device 20, 30, 41, 42 is read from the information input means 90 (step 201), pointer control is performed. Pointer control (step 202) and display control (step 203) of the pointer meters 21 and 31 corresponding to the means 811 are performed. Subsequently, display control of the liquid crystal display 40 corresponding to the liquid crystal display control means 812 (step 204) is performed, and luminance control of the backlight 42 corresponding to the backlight control means 813 is performed (step 205). The control values obtained in steps 202 to 205 are output to the drive circuits 82 to 84 (step 206).

  Next, the operation of steps 204 and 205 immediately after turning on and off of the ignition switch (IG switch) 100, which is a feature of the present invention, will be described with reference to FIGS.

  FIG. 5 is a flowchart of the liquid crystal display and backlight emission control portion, and FIG. 6 is a timing chart thereof.

  First, when the user gets on and the ignition switch 100 is turned on (step 301) as shown in FIGS. 6A and 6B, the liquid crystal display driving is started (step 302). At this time, when the elapsed time from the time when the ignition switch 100 is turned on is within a predetermined time t1 (a time for which the display feels smooth, for example, 1 to 2 seconds) (step 303), FIG. 6C. As shown in FIG. 4, so-called backlight luminance gradually increasing control is performed to gradually increase the light output level of the backlight 42 from the time when the ignition switch 100 is turned on (step 304). At this time, the light output level may be increased stepwise (stepwise) as indicated by a broken line, not continuously.

  On the other hand, when the time t1 has elapsed from the time when the ignition switch 100 is turned on, so-called steady-state control of the backlight brightness is performed in which the light output level of the backlight 42 is fixed to a target level determined based on illuminance information around the meter panel. Perform (step 305).

  Next, as shown in FIGS. 6A and 6C, the ignition switch 100 is turned off from on (step 301), and the elapsed time from the time when the ignition switch 100 is turned off is a predetermined time t2 (smooth display). When it is within a time when the user feels it (for example, 1 to 2 seconds) (step 306), the light output level of the backlight 42 is gradually lowered from the time when the ignition switch 100 is turned off. (Step 307). At this time, the light output level may be lowered stepwise (stepwise) as indicated by a broken line, not continuously.

  On the other hand, when the time t2 elapses from when the ignition switch 100 is turned off, the operation of the backlight 42 is stopped (off) (step 308), and the display of the liquid crystal display 40 is accordingly displayed as shown in FIG. 6B. The operation is stopped (step 309). At that time, the power supply to the liquid crystal display 40 may be stopped to save power.

  In the embodiment shown in FIG. 5, the display control of the pointer meters 20 and 30 shown in step 203 of FIG. 4 is performed independently of the control of the liquid crystal display 40 and the backlight 42 (steps 204 and 205). It is a structure to be called. Accordingly, only the pointers 21 and 31 are sequentially displayed from the time when the ignition switch 100 is turned on, the outer frames 20b and 30b are additionally displayed, the dials 20a and 30a are subsequently added, and finally the entire display panel 60 is displayed. Will be displayed.

  As described above, in the display device of the present invention, the front panel 50 made of the smoke lens is provided, and when the display is started by turning on the ignition switch 100, the liquid crystal display 40 is first started to stabilize the operation of the liquid crystal device. However, since the dimming level of the light output of the backlight 42 is gradually increased to the target level, a display effect can be obtained in which the video gradually emerges from a dark place as a display, and the appearance of the display section is improved. can do.

  In particular, in a combination meter of an automobile, the liquid crystal display 40 has a square shape, whereas the pointer meters 20 and 30 have many shapes based on a circle, but a combination meter in which both 20 to 40 are combined. Even in the case of design, it is possible to improve the appearance to the user by providing an effect that does not make the square shape of the liquid crystal display visually felt as in the present invention.

  Moreover, even when the operation of the liquid crystal device is not stable immediately after the ignition switch 100 is turned on, such as when the ambient environment is at a low temperature, the display unevenness can be made invisible by initially reducing the light output level of the backlight 42. Can do.

  Further, at the end of the display by turning off the ignition switch 100, the dimming level of the light output of the backlight 42 is gradually lowered to the off level, and the liquid crystal is interlocked with the time when it is turned off or immediately after it is completely turned off. Since the display operation of the display device 40 is stopped (off), it is possible to obtain an effect that the image gradually disappears in a clear image state, and the appearance of the display portion can be improved. In particular, even at the end of the display, it is possible to produce an effect that does not make the square shape of the liquid crystal display feel visually.

(Other embodiments)
In the above embodiment, as shown in FIGS. 5 and 6, the display control of the pointer meters 20 and 30 is configured to be performed independently of each control of the liquid crystal display 40 and the backlight 42, but in this embodiment, This is an example in which the effect is further enhanced by controlling display in association with each other.

  FIG. 7 is a timing chart of pointer display, liquid crystal display, and backlight emission control.

  The difference from the above-described embodiment is that, at the start of the display by turning on the ignition switch 100, the pointer display is preceded first, and the outer frames 20b, 30b of the dials 20a, 30a are additionally displayed after a predetermined elapsed time t0. Thus, the light output level of the backlight 42 is gradually increased, so-called backlight luminance gradually increasing control is performed.

  In this respect, as shown in FIGS. 7A to 7E, at the start of the display in which the ignition switch 100 is turned on from the OFF state, first, the pointer display and the operation of the liquid crystal display 40 are started, and the ignition switch 100 is turned on. After the elapse time t0 from the point of time, the outer frames 20b and 30b of the dials 20a and 30a are additionally displayed, and the light output level of the backlight 42 is gradually increased from the same point, so-called backlight luminance gradually increasing control is performed. .

  Thereafter, when the time t1 has elapsed from the time when the outer frames 20b and 30b are additionally displayed, the light output level of the backlight 42 is fixed to a target level determined based on illuminance information around the meter panel, etc. Steady state control is performed. On the other hand, the display is the same as the example shown in FIG.

  As described above, in the display device of the present invention, the front panel 50 made of the smoke lens is provided, and at the start of the display by turning on the ignition switch 100, the pointer display is preceded first. First, only the pointers 21 and 31 of the pointer meters 20 and 30 are displayed, and then the outer frames 20b and 30b are started on the pointer meters 20 and 30, and an image is gradually displayed on the liquid crystal display 40 from a dark place. It appears that it appears, and a production effect is obtained over the entire display panel 60 of the combination meter 1, and the appearance of the display unit can be improved.

  In the above embodiment, the increase / decrease rate in the backlight luminance gradual increase control and gradual decrease control is varied based on the illumination information around the meter panel, etc., so that the visibility of the display unit and the production effect are enhanced. Good. According to the timing chart shown in FIG. 7 (f), when the ambient illuminance is high such as during the daytime, the contrast between the meter panel and the panel periphery is low and the effect is diminished. Therefore, the elapsed time t11 for gradual increase control and gradual decrease control, t21 is made shorter than t1 and t2, and the target light output level is reached early.

  On the other hand, when the ambient illuminance is low, such as at night, the contrast between the meter panel and the periphery of the panel is high and the production effect is enhanced. The target light output level is slowly reached. At this time, by setting the light output level of the backlight 42 to a target level determined based on illuminance information around the meter panel, etc., the contrast of the light-emitting display image can be stabilized and easy to see.

It is a front view of the combination meter 1 in one Embodiment of this invention. It is the II sectional view taken on the line in FIG. 3 is a block diagram showing a schematic configuration of a control device 80. FIG. 3 is a flowchart showing a schematic control content of a control device 80. It is a flowchart of a liquid crystal display and a backlight light emission control part. It is a timing chart of liquid crystal display and backlight emission control. 10 is a timing chart of pointer display, liquid crystal display, and backlight emission control in another embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Combination meter 10 Case 20, 30 Pointer meter 20a, 30a Dial 20b, 30b Outer frame 21, 31 Pointer 22 Movement 40 Liquid crystal display 41 Liquid crystal panel 42 Backlight (backlight means)
50 Front panel (Light transmittance adjustment panel)
60 Display panel 80 Control device (control means)
81 Control circuit 90 Information input means 100 Ignition switch (power switch)
811 Pointer control means 812 Liquid crystal display control means 813 Backlight control means

Claims (3)

A liquid crystal display,
Backlight means for making light incident on the liquid crystal display from the back,
A light transmittance adjusting panel provided on the front surface of the liquid crystal display;
A liquid crystal display device comprising: a liquid crystal display; and a control means for controlling the operation of the backlight means, wherein a light emission display image of the liquid crystal display is viewed through the light transmittance adjustment panel. ,
When the display is finished, the control means gradually lowers the dimming level of the light output of the backlight means, and terminates the display of the liquid crystal display when the dimming level falls below a predetermined level. A characteristic liquid crystal display device. 2. The liquid crystal display according to claim 1 , wherein at the start of display, the control unit starts display on the liquid crystal display and gradually increases the dimming level of the light output of the backlight unit. apparatus. The control means is a liquid crystal display control means for starting a display operation of the liquid crystal display when receiving a power switch on signal, and a light control level of the light output of the backlight means when receiving the on power signal. The liquid crystal display device according to claim 2, further comprising backlight control means for gradually increasing the height .

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