JP2004348076A - Display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a display device having an easily visible screen since the luminance of a display is not changed by neglecting an illuminance sensor for a prescribed time even when the illuminance sensor is blocked by the hand or arm due to the user's operation of a switch etc. <P>SOLUTION: The display device is equipped with an illuminance detecting means which detects the illuminance of external light illuminated to a display part or the vicinity of the display part, a luminance control means which controls the luminance of the display element on the basis of the illuminance detected by the illuminance detecting means, and an operation switch section which is disposed in the vicinity of the illuminance detecting means and is manually operated by the user. The luminance control means holds the luminance during the operation of the operation switch section for the prescribed time after the operation of the operation switch section is detected. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a display device that changes luminance of a display unit according to external illuminance.
[0002]
[Prior art]
Conventionally, there has been considered a display device that makes it easier to view the screen by detecting the illuminance of external light applied to the screen with an illuminance sensor or the like provided near the screen and changing the brightness of the screen according to the illuminance ( For example, see Patent Document 1).
[0003]
[Patent Document 1]
JP-A-6-331962 (pages 4-6, FIG. 1)
[0004]
[Problems to be solved by the invention]
However, for example, in a display device such as an in-vehicle navigation device, it is necessary to arrange a screen, an operation switch, an illuminance sensor, and the like in a limited space. Therefore, in the related art, for example, when the user tries to operate the switch and creates a shadow with the hand or arm near the illuminance sensor, the display device is dark even though the surroundings are very bright and the surroundings are sunny. And the screen brightness is reduced for a predetermined time. Therefore, even when the operation is completed and the user releases his / her hand and the screen becomes bright, there is a problem that the screen is dark for a predetermined time and the screen becomes difficult to see.
[0005]
The present invention has been made in view of the above points, and it is an object of the present invention to provide a display device in which the brightness of the screen is not changed even when the screen is temporarily darkened by a user's operation of a switch or the like so that the screen can be easily viewed. With the goal.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, a display device of the present invention includes: an illuminance detection unit configured to detect illuminance of external light emitted to a display unit or a vicinity of the display unit; A display device comprising: a brightness adjustment unit that adjusts the brightness of the unit; and an operation switch unit that is provided near the illuminance detection unit and that is manually operated by a user.
The brightness adjusting unit holds the brightness when the operation switch unit is operated for a predetermined time after detecting that the operation switch unit has been operated.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiment is a display device of an in-vehicle navigation device. FIG. 1 is a block diagram showing a configuration of a main part of the navigation device.
[0008]
The navigation device has a control circuit (1) for controlling each section based on a program written in a ROM (2), and a RAM (3) for storing information necessary for the operation of the control circuit (1). Then, a GPS (Global Positioning System) receives radio waves from the satellite and measures the current position, and outputs a measurement data to the control circuit (1). It has a map storage unit (5) for reading information. And it has the display part (6) which displays map information, the present position, etc. based on control of the control circuit (1).
[0009]
The display unit (6) includes a liquid crystal panel (61) and a backlight (62). Based on an instruction from the control circuit (1), the map information and the GPS receiving unit stored in the map storage unit (5). The current position obtained from (4) is displayed on the liquid crystal panel (61), and the backlight (62) is turned on. (7) is a touch panel-type operation unit (7) provided on the liquid crystal panel (61) and capable of detecting and inputting a touch by a user. Note that the operation unit is not limited to the touch panel type described above, and may be a switch provided near the display unit (6). (8) an illuminance sensor that measures the illuminance on the liquid crystal panel (61) and / or near the liquid crystal panel (61) and outputs the measured illuminance to the control circuit (1). Thereby, the operation unit (7) is located near the illuminance sensor (8). Therefore, when the operation unit (7) is manually operated by the user, the illuminance sensor (8) is shaded by a hand or an arm.
[0010]
The control circuit (1) controls the luminance of the backlight (62) according to the illuminance detected by the illuminance sensor (8). FIG. 2 is an explanatory diagram showing the relationship between the illuminance detected by the illuminance sensor (8) and the luminance of the backlight (62). In FIG. 2, the Y axis indicates the illuminance detected by the illuminance sensor (8), and the X axis indicates the luminance of the backlight (62). A straight line L is an initial setting indicating a standard relationship between luminance and illuminance. X1 is luminance with respect to illuminance Y1, X2 is luminance with respect to illuminance Y2, and the straight line L is defined by these initial values. In this case, the slope a of the straight line L is represented by a = (Y2-Y1) / (X2-X1) (Equation 1). The Y intercept b of the straight line L is represented by b = Y1−aX1 (Equation 2). Therefore, for example, when the illuminance is Yc, the luminance Xc of the backlight (62) is Xc = (Yc−b) / a (Equation 3).
[0011]
Next, the operation of the control circuit (1) of this embodiment will be described with reference to the flowchart of FIG. First, when the power of the navigation device is turned on, the current position measured by the GPS receiving unit (4) and the map information read from the map storage unit (5) are displayed on the liquid crystal panel (61). Based on the illuminance detected by the illuminance sensor (8), the luminance is calculated based on the above-described (Equation 3), the backlight (62) is turned on at the luminance, and whether the operation unit (7) is operated is determined. Is determined (step S1).
[0012]
When it is determined in step S1 that the operation unit (7) is not operated (N in step S1), the illuminance is measured by the illuminance sensor (7) (step S2), and the luminance corresponding to the measured illuminance is measured. To turn on the backlight (62) (step S3).
[0013]
If it is determined in step S1 that the operation section (7) has been operated, a predetermined time is measured (step S4). If a predetermined time has elapsed since the operation (Y in step S4), the process proceeds to step S2 to measure the illuminance. I do.
[0014]
In the above-described embodiment, the liquid crystal panel (61) and the backlight (62) are used for the display unit, and the luminance of the backlight (62) is controlled according to the illuminance. However, the display unit is not limited to this. Instead, the brightness may be adjusted using a CRT for the display unit.
[0015]
【The invention's effect】
According to the present invention, even if the illuminance sensor is shaded by a hand or an arm by a user's operation of a switch or the like, the brightness of the display is not changed by ignoring the illuminance sensor for a predetermined period of time. An apparatus can be provided.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a main part of a navigation device using the present invention.
FIG. 2 is an explanatory diagram showing a relationship between illuminance and luminance.
FIG. 3 is a flowchart showing the operation of the control circuit of the present invention.
[Explanation of symbols]
Reference Signs List 1 control circuit 6 display unit 61 liquid crystal panel 62 backlight 7 operation unit 8 illuminance sensor

Claims (1)

Illuminance detection means for detecting the illuminance of external light applied to the display unit or the vicinity of the display unit; brightness adjustment means for adjusting the brightness of the display unit based on the illuminance detected by the illuminance detection means; An operation switch unit provided near the means and manually operated by a user;
The display device, wherein the brightness adjustment unit holds the brightness at the time of operating the operation switch unit for a predetermined time after detecting that the operation switch unit has been operated.

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