JP2958073B2 - Display device for vehicles - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vehicle display device capable of adjusting the brightness of a display in accordance with the brightness of the outside world.

(Prior art) Conventionally, in this type of vehicle display device, based on the detection result of the brightness by the auto light control device, at the same time as the headlight is turned on, the brightness of the backlight of the display such as a speedometer is reduced, The brightness was raised simultaneously with the headlight off.

(Problems to be Solved by the Invention) However, in the above-described conventional example, since the brightness of the display is changed simply in conjunction with the on / off of the headlight, for example, the vehicle enters from a bright place to a dark place in the outside world. When this happens, the brightness of the display sharply drops, and at that moment, the display becomes very difficult to see. On the other hand, when the display goes from a dark place to a bright place in the outside world, there is a problem that the display becomes difficult to see due to insufficient increase in display brightness.

(Means for Solving the Problems) The present invention has been made for the purpose of solving the above problems, and has the following configuration as one means for solving the above problems. That is, a display device for a vehicle that detects the illuminance of the external environment of a vehicle and automatically controls the luminance of the display device, and a changing unit that changes the luminance of the display device according to a change in the illuminance of the external environment of the vehicle. Wherein when the illuminance of the outside of the vehicle changes from bright to dark, the change means changes the brightness of the display so as to reduce the rate of change of the illuminance as the difference in illuminance increases, and When the illuminance changes from dark to bright, the brightness of the display is sharply increased.

(Operation) In the above configuration, when the external environment of the vehicle changes from light to dark, or when the illuminance of the external environment changes from dark to bright, it is possible to realize a luminance change that is closer to the occupant's vision (pupil change), Good visibility can be maintained.

Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a block diagram showing the configuration of a vehicle display device according to an embodiment of the present invention. In FIG. 1, a vehicle display device (hereinafter, referred to as a device) 1 has an automatic light control function, and a CPU 2 detects an insolation sensor 20 and converts the signal into a digital signal by an A / D converter 11. The headlight controller 3 is controlled to turn on or off the headlight 8 in accordance with the brightness information of the outside of the vehicle. The headlight 8 can be turned on or off by manually turning on / off the light switch 9.

The CPU 2 quantifies the brightness of the outside world within a certain time, based on the brightness information continuously transmitted from the solar radiation sensor 20 and the A / D converter 11, as described later. Then, the quantified values are sequentially recorded in the recording unit 5, and are used as data for determining the luminance of the display, which will be described later.

The display controller 4 sends a control signal to the display drive unit 6 under the control of the CPU 2 to change the brightness by adjusting the back illumination current value of the display 7 such as a speedometer or a clock.

Here, a method of quantifying the brightness of the external world will be briefly described.

The CPU 2 samples the information (digital signal) regarding the brightness of the external world continuously transmitted by the A / D conversion unit 11 at a cycle t, and simultaneously samples the sampled values at intervals of a cycle T (T> t). Find the average value. The calculated average is
It is stored in the recording unit 5. Here, the period T is the time required for the human (here, the driver) eyes to become accustomed to the change in the external brightness, that is, from “bright” to “dark” or from “dark” to “bright”. Is set long enough.

Note that the recording in the recording unit 5 employs a method of overwriting old information with new information, so that only the latest brightness information is always stored.

FIG. 2A is a diagram showing the relationship between the on / off of the headlight and the current flowing through the display 7.

In FIG. 2 (a), at work automatic light control function of the device 1, the Hetsudoraito (TNS / HL) is turned on at point, the indicator current I _B flowing in the time of head light-off relaxation time t _m elapses Later, it decreases to _ID . And
When Hetsudoraito is turned off at point, the indicator current from I _D
At once to increase the I _B. Brightness of the display unit 7 is proportional to the current flowing therethrough, bright luminance of the display unit 7 there is a high current value when the indicator current I is I _B, dark luminance when the contrary I = I _D .

Figure 2 (b), the vehicle is a diagram showing the relationship between the illuminance difference between the above-mentioned relaxation time t _m when the transition from the outside bright place to a dark place, as the photometric Δ is large, the relaxation time t It means taking _m longer. In other words, the greater the difference in illuminance received before and after the vehicle enters the tunnel, for example,
The luminance of the display 7 is gradually decreased by increasing the relaxation time t _m . This makes it difficult for the driver to perceive a change in the brightness of the display with respect to a change in the brightness of the outside world.

The illuminance difference Δ and the relaxation time t _m have a linear relationship of t _m = a · Δ + b (a and b are constants).

When the headlight is off (point in FIG. 2 (a)), there is an illuminance difference corresponding to “bright” to “bright” with respect to the vehicle. Irrespective of the degree of the above, the display current I is sharply increased, and the brightness is increased at a stretch.

Next, a control procedure in the CPU of the device 1 of the embodiment will be described with reference to the flowchart shown in FIG. In FIG. 7, the CPU 2 determines whether or not TNS / HL (head lamp) has changed from off to on in step S1. If the result of this determination is YES, it is determined that the vehicle has entered a dark place from a bright place in the outside world, and in step S2, the brightness of the outside world where the vehicle is located at that time is represented by brightness information ( D and _P) is detected by the data from the a / D converter 11 as. Then, it continues in step S3, read from the recording unit 5, the latest brightness information which has been accumulated (and D _L). This brightness information D _L is information about the illuminance that the vehicle was receiving immediately before the illuminance change occurred.Taking the case where the vehicle enters a tunnel as an example, the brightness information D _L is the brightness outside the tunnel. Corresponding.

In step S4, the calculated difference, i.e. the Δ between the step S2, brightness information obtained by the S3 D _P and D _L, the following step
In S5, determines the relaxation time t _m at the indicated calculation formula Figure 2 (b) based on the difference. Determined relaxation time t _m is the step S6, and sent to the display controller 4 from CPU 2.
The display controller 4 controls the display drive unit 6 based on the input relaxation time t _m , adjusts the value of the display current I, and gradually lowers the brightness of the display 7.

On the other hand, if the determination in step S1 is NO, step S7
To determine whether TNS / HL (headlamp) has changed from on to off. If the result of the determination is YES, the vehicle that it comes to where a bright from the place dark outside, the indicator current I in the I _B in order to brighten once the luminance of the display unit 7 as described above, the present process To end.

If the determination in step S7 is NO, there is no change in TNS / HL (head lamp), so the process proceeds to step S9.
The process is terminated while maintaining the display current at that time.

As described above, according to the present embodiment, when a vehicle enters a dark place from a bright place in the outside, the auto light control is activated and the headlight is turned on, and at the same time, the illuminance difference to the vehicle at that time is reduced. In response, the brightness of the display is gradually reduced, and conversely, when the vehicle shifts from a dark place to a bright place, the brightness of the display is increased at a stretch, so that the driver's eyes can respond to changes in the brightness of the outside world. Since the change in the brightness of the display device is hardly perceived, there is an effect that the display device can always be in a state that is easy to see.

(Effects of the Invention) As described above, according to the present invention, when the illuminance of the outside of the vehicle changes from bright to dark, as the illuminance difference increases,
Change the brightness of the display to reduce the rate of change in illuminance,
When the illuminance of the outside of the vehicle changes from dark to bright, the brightness of the display is sharply increased, so that a brightness change more approximate to the occupant's vision (pupil change) can be realized, and good visibility can be maintained.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a vehicular display device according to an embodiment of the present invention. FIG. 2 (a) is a diagram showing a relationship between on / off of a headlight and a current flowing through a display. FIG. 2 (b) shows the relationship between the illuminance difference and the relaxation time when the vehicle moves from a bright place to a dark place in the outside world. FIG. 3 is a flowchart showing a control procedure by the CPU of the apparatus. In the drawing, 1 ... vehicle display device, 2 ... CPU, 3 ... headlight controller, 4 ... display controller, 5 ...
... Recording unit, 6 ... Display drive unit, 7 ... Display unit, 8 ... Head light, 9 ... Light switch, 10 ... Battery,
11: A / D converter, 20: solar radiation sensor.

Continued on the front page (56) References JP-A-3-86641 (JP, A) JP-A-2-35027 (JP, U) JP-A-59-37144 (JP, U) JP-A-59-105797 (JP) , U) Jpn. 4-35939 (JP, U) (58) Field surveyed (Int. Cl. ⁶ , DB name) B60Q 3/04 B60Q 1/04

Claims (1)

(57) [Claims] 1. A display device for a vehicle for automatically controlling the luminance of a display device by detecting the illuminance of the external environment of a vehicle, wherein the luminance of the display device is changed according to a change in the illuminance of the external environment of the vehicle. When the illuminance of the outside of the vehicle changes from bright to dark, the changing means changes the luminance of the display so that the rate of change of the illuminance decreases as the illuminance difference increases. When the illuminance of the outside of the vehicle changes from dark to bright, the brightness of the display increases sharply.