JP2010034914A - Mobile terminal - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile terminal which is simply in configuration and can always operate an illuminator normally regardless of a tilting attitude of a cabinet. <P>SOLUTION: In the mobile terminal, an illuminator, an illuminance sensor 7 which is irradiated with light incident through a light-receiving window 13, a control circuit for controlling operations of the illuminator in accordance with illuminance detected by the illuminance sensor 7, and a tilting sensor for detecting a tilting angle of a cabinet 1 are arranged inside the cabinet 1. In the control circuit, a relationship representing lightness around the cabinet 1 is predetermined with the tilting angle of the cabinet 1 and the illuminance detected by the illuminance sensor 7 as variables. While using the relationship, the lightness around the cabinet 1 is derived from the tilting angle of the cabinet detected by the tilting sensor and the illuminance detected by the illuminance sensor 7 and in accordance with the derived ambient lightness, the operations of the illuminator are controlled. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a portable terminal having a portable cabinet such as a cellular phone.

Conventionally, in a mobile phone, a key input device including a plurality of operation keys and a liquid crystal display are provided on the surface of the cabinet, and a backlight for illuminating the key input device from the back or a back of the liquid crystal display is provided inside the cabinet. Lights etc. are arranged.
These backlights are controlled in luminance and on / off according to the brightness around the cabinet (see Patent Document 1).

For example, as shown in FIG. 11A, an illuminance sensor (7) is installed on a circuit board (9) installed inside the cabinet (1), and light from a light source is provided on the cabinet (1). By passing through the light receiving window (13) and entering the illuminance sensor (7), the brightness around the cabinet (1) is detected by the illuminance sensor (7).
JP 2008-158871 A

  However, in the conventional mobile phone, when the cabinet (1) is inclined as shown in FIG. 11 (b), the light from the light source passes through the light receiving window (13) and then has an illuminance sensor (7 11), the output signal (illuminance) of the illuminance sensor (7) is smaller than that when the light is incident perpendicularly to the surface of the illuminance sensor (7) as shown in FIG. The brightness around (1) is detected to be darker than actual.

FIG. 12 shows the illuminance at an arbitrary inclination angle θ as a ratio (sensitivity characteristic) based on the illuminance detected by the illuminance sensor when the inclination angle θ of the cabinet is zero, and the inclination angle θ is large. As time goes on, the sensitivity will decrease.
This is because the illuminance sensor (7) must be arranged behind the light receiving window (13) (for example, several millimeters behind) as shown in FIG. 11 (b), so that the light flux irradiated on the surface of the cabinet (1) is reduced. This is because there is a difference according to the inclination angle θ between the amount of light and the amount of light flux that passes through the light receiving window (13) and enters the illuminance sensor (7).

As a result, if the backlight of the key input device is used, it is lit even though it is not necessary to illuminate, and there is a problem that wasteful power is consumed. In addition, if the backlight of the display, it is necessary to emit light with high luminance, but it emits light with low luminance, and there is a problem that it is difficult to see the image on the display.
In order to solve this problem, a method of guiding light to the illuminance sensor (7) using a reflector or the like or a method of enlarging the light receiving window (13) can be adopted. , Design and cost problems arise.

  Accordingly, an object of the present invention is to provide a portable terminal having a simple configuration that can always operate a lighting device normally regardless of the inclination posture of a cabinet.

  In the portable terminal according to the present invention, an operation unit and / or a display unit are provided on the surface of a portable cabinet, and a light receiving window is formed, and the operation unit and / or the display unit is provided inside the cabinet. Illuminating device to illuminate, an illuminance sensor irradiated with light incident through the light receiving window, and a control circuit for controlling the operation of the illuminating device according to the illuminance detected by the illuminance sensor. Yes.

Here, an inclination sensor that detects an inclination angle with respect to a reference attitude of the cabinet is provided inside the cabinet, and the control circuit includes:
Relation defining means in which a relation representing the brightness around the cabinet is defined, with the angle of inclination of the cabinet and the illuminance detected by the illuminance sensor as variables,
Brightness deriving means for deriving brightness around the cabinet from the tilt angle of the cabinet detected by the tilt sensor and the illuminance detected by the illuminance sensor, using the relationship defined in the relationship defining means. When,
Control means for controlling the operation of the lighting device according to the ambient brightness derived by the brightness deriving means.

  According to the portable terminal of the present invention, from the cabinet tilt angle detected by the tilt sensor and the illuminance detected by the illuminance sensor, when the cabinet is installed in a reference posture (when the tilt angle is zero). The brightness around the cabinet according to the illuminance is derived. The brightness derived in this way represents the actual brightness of the surroundings regardless of the inclination angle of the cabinet.

  In a specific configuration, the relationship defining means defines the relationship for each inclination direction when the cabinet is inclined in a plurality of directions around a plurality of horizontally extending rotation shafts, and the brightness deriving means includes: The inclination direction of the cabinet is detected based on the output signal of the inclination sensor, one relationship is determined according to the detected inclination direction, and the brightness around the cabinet is derived using the relationship.

  According to the specific configuration, since the ambient brightness is derived in consideration of the inclination direction of the cabinet, the operation of the lighting device can be controlled more accurately.

In a more specific configuration, the control means adjusts the light emission luminance of the lighting device according to the ambient brightness derived by the brightness deriving means.
Alternatively, the control means turns on / off the illumination device according to the ambient brightness derived by the brightness deriving means.

  According to the portable terminal of the present invention, since the illumination control according to the actual ambient brightness is executed regardless of the inclination angle of the cabinet, the illumination device can always be operated normally with a simple configuration. I can do it.

Hereinafter, embodiments of the present invention in a mobile phone will be described in detail with reference to the drawings.
As shown in FIG. 1, the mobile phone according to the present invention is provided with a display (12) and a key input device (11) on the surface of a cabinet (1) and a light receiving window (13). Further, a transmitter (14) is provided at the lower part of the surface of the cabinet (1), and a receiver (15) is provided at the upper part.

  Inside the cabinet (1), as shown in FIG. 2, a communication circuit (2) for telephone communication, a control circuit (3) composed of a microcomputer, and a microphone (4) constituting the transmitter (14) The speaker (5) constituting the receiver (15), the illumination device (6) serving as the backlight of the key input device (11) and the display (12), and the light incident from the light receiving window (13) should be received. An illuminance sensor (7) and an acceleration sensor (8) are provided.

  The acceleration sensor (8) is mounted on the circuit board (9) as shown in FIG. 3, and as part of its output signal, the X-axis, Y-axis, and circuit parallel to the surface of the circuit board (9). Values (XX, YY, ZZ) of gravity acceleration components in the Z-axis direction perpendicular to the substrate (9) can be obtained.

The control circuit (3) calculates the inclination direction and the inclination angle θ of the circuit board (9) based on the values (XX, YY, ZZ) of the three gravitational acceleration components obtained from the acceleration sensor (8).
In the three-axis absolute coordinate system shown in FIG. 4, with reference to the horizontal plane defined by the Xo axis and the Yo axis, the tilt direction (vertical direction) A by rotation around the Xo axis and the tilt direction (left / right direction) by rotation around the Yo axis ) B and an inclination direction (oblique direction) C about 45 ° with respect to the Xo axis and the Yo axis are set, and each inclination direction has a width of 45 °, the circuit board (9 ) Can be any one of these three tilt directions A, B, and C.

Further, the inclination angle θ of the circuit board 9 can be calculated from the relational expression of cos θ = ZZ / 100 based on the gravitational acceleration component value ZZ obtained from the acceleration sensor 8 as shown in FIG. (When the output value corresponding to 1G is 100).
FIG. 7 shows a gravity acceleration component value ZZ corresponding to the inclination angle θ (0 ° to 180 °).

  The control circuit (3) stores three tables as shown in FIGS. 5 (a), 5 (b) and 5 (c). In the table of FIG. 5 (a), when the circuit board (9) is inclined in the vertical direction, the inclination angle θ of the circuit board (9) is lower than the surrounding brightness (100Lx, 500Lx, 1000Lx, 3000Lx). It shows an example of the illuminance detected by the illuminance sensor when it changes in the range of -90 ° to 0 ° to 90 °. Further, the table of FIG. 5B shows the inclination angle θ of the circuit board 9 under ambient brightness (100Lx, 500Lx, 1000Lx, 3000Lx) when the circuit board 9 is tilted in the left-right direction. Shows an example of the illuminance detected by the illuminance sensor when changes in the range of (−90 ° to 0 ° to 90 °). Furthermore, the table of FIG. 5C shows the inclination angle θ of the circuit board 9 under the ambient brightness (100Lx, 500Lx, 1000Lx, 3000Lx) when the circuit board 9 is inclined in the oblique direction. Shows an example of the illuminance detected by the illuminance sensor when changes in the range of (−90 ° to 0 ° to 90 °).

  These tables are based on the illuminance data acquired by changing the incident angle of light to the illuminance sensor (7) under a general light source that exists above the head like sunlight or a fluorescent lamp. The optimum values that can correspond to the conditions are calculated and tabulated.

  For example, when the tilt direction is the vertical direction, if the tilt angle is 10 ° and the illuminance detected by the illuminance sensor is 94, if the tilt angle is 0 ° under the light source (1000Lx) at that time, the illuminance is When 100 is obtained, the illuminance is detected as 94 by the inclination of 10 °. In this case, when the conventional illumination control is performed with an illuminance of 94, the result is determined to be darker than the actual surrounding brightness (1000 Lx). For example, in the case of the backlight of the key input device, the backlight has a brightness higher than necessary. It will be lit and wasteful power is consumed.

  On the other hand, in the mobile phone according to the present invention, in the above example, if the inclination angle of the cabinet is 10 ° and the illuminance detected by the illuminance sensor is 94, the brightness around the cabinet is 1000 Lx. Judgment is performed and illumination control is performed according to the brightness.

For example, in the case of the backlight of the liquid crystal display (12), as shown in FIG. 8, the light emission luminance is changed stepwise according to the ambient brightness.
In the case of the backlight of the key input device (11), on / off is switched depending on whether the ambient brightness exceeds a predetermined threshold as shown in FIG.

FIG. 10 shows a procedure of brightness derivation and illumination control executed by the control circuit (3).
First, in step S1, it is determined whether or not any operation event such as key operation or opening / closing of the lid has occurred. If it is determined as YES, the process proceeds to step S2, and the X, Y and Z axes are detected by the acceleration sensor. Acquire triaxial data (XX, YY, ZZ) of the axis.
Next, in step S3, the three tilt directions (up / down, left / right, oblique) of the cabinet are determined from the X-axis data XX and the Y-axis data YY, and the tilt angle θ is calculated from the Z-axis data ZZ and used. Decide which table to use.

Subsequently, in step S4, illuminance data is acquired from the illuminance sensor.
Thereafter, in step S5, ambient brightness is derived from the tilt angle and illuminance data using the determined table. When applying the table, interpolation processing is performed as necessary.
In step S6, illumination control is executed according to ambient brightness.

  According to the mobile phone of the present invention, from the inclination angle θ of the cabinet (1) detected by the acceleration sensor (8) and the illuminance detected by the illuminance sensor (7), regardless of the inclination of the cabinet (1). Since the actual ambient brightness is derived and the illumination control according to the brightness is executed, the illumination device (6) can always be operated normally. In addition, since the acceleration sensor (8) is simply installed and the above control is executed by the control circuit (3), the configuration is not complicated.

  In addition, each part structure of this invention is not restricted to the said embodiment, A various deformation | transformation is possible within the technical scope as described in a claim. The tilt sensor is not limited to the acceleration sensor (8), and various sensors that can detect the tilt angle, such as a gyroscope, can be employed.

  Also, in deriving the brightness according to the tilt angle of the cabinet, the three tilt directions (up and down, left and right, diagonal) of the cabinet are determined based on the X axis data XX and Y axis data YY from the acceleration sensor (8). Not only the method of determining and determining one table to be used, but also the X-axis component and Y-axis component in the cabinet tilt direction based on the X-axis data XX and Y-axis data YY from the acceleration sensor (8). It is also possible to employ a method of calculating the ambient brightness using both the table shown in FIG. 5A and the table shown in FIG.

  In addition, the present invention is not limited to a portable terminal having a single cabinet as shown in FIG. 1, and may be implemented in a foldable or sliding portable terminal in which two cabinets are connected so as to be openable and closable. Is possible. In this case, it is desirable to arrange the illuminance sensor and the acceleration sensor in the same cabinet.

1 is a perspective view of a mobile phone according to the present invention. It is a block diagram which shows the structure of this mobile telephone. It is a perspective view which shows the acceleration sensor on a circuit board. It is a figure explaining the inclination direction of a cabinet. It is a chart which shows three tables for deriving ambient brightness. It is a figure explaining the detection method of the inclination angle by an acceleration sensor. It is a graph which shows the value of the gravity acceleration component according to an inclination angle. It is explanatory drawing showing an example of the illumination control with respect to a display. It is explanatory drawing showing an example of the illumination control with respect to a key input device. It is a flowchart showing the procedure of the brightness derivation | leading-out and illumination control by a control circuit. It is a figure explaining that the sensitivity of an illumination intensity sensor changes with the inclination of a cabinet. It is a graph which shows the change of the sensitivity of the illumination intensity sensor according to an inclination angle.

Explanation of symbols

(1) Cabinet
(11) Key input device
(12) Display
(13) Light receiving window
(2) Communication circuit
(3) Control circuit
(6) Lighting device
(7) Illuminance sensor
(8) Accelerometer
(9) Circuit board

Claims (4)

An operation unit and / or a display unit are provided on the surface of the portable cabinet, and a light receiving window is formed. Inside the cabinet, an illumination device for illuminating the operation unit and / or the display unit, and the light receiving unit In a mobile terminal in which an illuminance sensor irradiated with light incident through a window and a control circuit that controls the operation of the illumination device according to the illuminance detected by the illuminance sensor are provided,
An inclination sensor that detects an inclination angle with respect to a reference posture of the cabinet is disposed inside the cabinet, and the control circuit includes:
A relationship defining means in which a relationship representing the brightness around the cabinet is defined, with the angle of inclination of the cabinet and the illuminance detected by the illuminance sensor as variables,
Brightness deriving means for deriving brightness around the cabinet from the tilt angle of the cabinet detected by the tilt sensor and the illuminance detected by the illuminance sensor, using the relationship defined in the relationship defining means. When,
A portable terminal comprising: control means for controlling the operation of the lighting device in accordance with ambient brightness derived by the brightness deriving means.   The relationship defining means defines the relationship for each inclination direction when the cabinet is inclined in a plurality of directions around a plurality of horizontally extending rotating shafts, and the brightness deriving means includes the inclination sensor 2. The portable terminal according to claim 1, wherein a tilt direction of the cabinet is detected based on the output signal, one relationship is determined according to the detected tilt direction, and brightness around the cabinet is derived using the relationship. Machine.   The portable terminal according to claim 1 or 2, wherein the control unit adjusts the light emission luminance of the lighting device according to the ambient brightness derived by the brightness deriving unit.   The portable terminal according to claim 1, wherein the control unit is configured to turn on / off the lighting device according to ambient brightness derived by the brightness deriving unit.

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