JP4421368B2 - Backlight control device and portable terminal device - Google Patents

Description

  The present invention relates to a backlight control device for a display such as a liquid crystal display (LCD) provided in a portable terminal device or the like, and a portable terminal device.

Conventionally, a portable terminal device or the like has a backlight using an LED (Light Emitting Diode) together with an LCD for screen display, and adjusts the brightness of the screen by changing the brightness of the backlight. Can be done. However, since much power is consumed when the backlight is turned on, the pulse width for driving the LED for the backlight is changed according to the remaining battery level in order to extend the battery life (for example, patents). Reference 1). In addition, the life of the battery is extended by limiting the LEDs that are actually driven according to the remaining battery capacity (see, for example, Patent Document 2).
JP 2001-168983 A JP 2002-374349 A

  However, the conventional LCD backlight control technology for reducing power consumption described above may not be convenient for the user. For example, in recent years, a mobile terminal device with a camera (such as a mobile phone with a camera) has been realized, but a camera image is displayed on an LCD with a low backlight brightness in a low power consumption mode according to a user setting or the like. Since the image is felt dark or noise due to insufficient brightness is noticeable, the appearance of the camera image deteriorates. In this case, there is a possibility that the user mistakes that the camera image itself is not clear.

  The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a backlight control device capable of appropriately controlling the screen display environment by the LCD.

  Another object of the present invention is to provide a portable terminal device provided with the backlight control device of the present invention.

In order to solve the above-described problems, a backlight control device according to the present invention is a backlight control device that controls a backlight of a display, an imaging device that inputs an image to be displayed on the display, and activation of the imaging device Imaging device activation detection means for detecting the brightness, brightness setting means for setting the brightness of the backlight based on a user operation, and brightness control means for controlling the brightness of the backlight, the brightness control means , In the case where the backlight is driven according to the user-set brightness set by the brightness setting means, when the image pickup apparatus start-up is detected by the image pickup apparatus start-up detection means, the user-set brightness The brightness of the backlight is controlled so that the brightness is high .

The backlight control device according to the present invention is a backlight control device that controls the backlight of a display, and detects communication connection by acquiring and inputting display data to be displayed on the display by communication, and communication connection by the communication device. A communication connection detecting unit; a luminance setting unit configured to set the luminance of the backlight based on a user operation; and a luminance control unit configured to control the luminance of the backlight. The luminance control unit includes the luminance setting unit. When the backlight is driven according to the user-set brightness set in the above, when the communication connection is detected by the communication connection detecting means, the brightness is higher than the user-set brightness. Controlling the brightness of the backlight .

In the backlight control device according to the present invention, the luminance setting means can set the luminance of the backlight based on the user operation from a plurality of luminance levels, and the luminance control means can respond to the plurality of luminance levels. The luminance of the backlight is controlled so that the luminance is higher than any luminance .

  The backlight control apparatus according to the present invention includes a luminance offset value storage unit that holds a luminance offset value, and the luminance control unit increases the luminance by the luminance offset value.

Mobile terminal device according to the present invention comprises a display, a backlight of the display, an imaging device for inputting an image to be displayed on said display, an imaging device activation detection means for detecting that the imaging apparatus is started, A luminance setting unit configured to set the luminance of the backlight based on a user operation; and a luminance control unit configured to control the luminance of the backlight. The luminance control unit includes a user setting set by the luminance setting unit. When the backlight is driven in accordance with the luminance of the backlight, when the imaging device activation detection unit detects the activation of the imaging device, the luminance of the backlight is set to be higher than the luminance set by the user. And a backlight control device for controlling luminance .

A mobile terminal device according to the present invention includes a display, a backlight of the display, a communication device that acquires and inputs display data to be displayed on the display, and a communication connection detection unit that detects a communication connection by the communication device And a brightness setting means for setting the brightness of the backlight based on a user operation, and a brightness control means for controlling the brightness of the backlight, the brightness control means being set by the brightness setting means When the backlight is driven according to the brightness set by the user, the brightness of the backlight is set to be higher than the brightness set by the user when the communication connection is detected by the communication connection detecting means. And a backlight control device for controlling the backlight .

  According to the present invention, in a situation where the brightness of the LCD screen is desired (when the camera is activated or communication is established), the brightness of the LCD backlight increases, so the LCD screen becomes brighter and the camera image displayed on the screen is displayed. Display data becomes clear.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing the configuration of the mobile terminal device 1 according to the first embodiment of the present invention. A mobile terminal device 1 shown in FIG. 1 is a mobile terminal device with a camera, for example, a mobile phone with a camera. FIG. 1 shows only the configuration according to the present invention.

  In FIG. 1, a camera activation detection unit 12 detects that the camera 11 has been activated. This detection signal is output to the luminance control unit 13. The luminance control unit 13 drives the backlight LED 15 based on the setting value of the luminance setting unit 14. The backlight LED 15 emits light when a drive current corresponding to the current limiting resistor R flows from the power supply 16 by a drive signal from the luminance control unit 13. The LCD screen display unit 17 displays input display data on the screen, and the brightness of the screen can be adjusted by the light emission of the backlight LED 15. An image being captured by the camera 11 or an image that has already been captured and stored in a memory (not shown) can be input to the LCD screen display unit 17 and displayed on the screen.

FIG. 2 is a block diagram illustrating the configuration of the luminance control unit 13 and the luminance setting unit 14 of FIG.
In FIG. 2, the luminance control unit 13 includes a selection unit 21 and a PWM (Pulse Width Modulation) output unit 22. The luminance setting unit 14 includes a CPU 31, a PWM setting value register 32, and a PWM setting value register 33 at the time of imaging.

  In the PWM setting value register 32, a PWM setting value for when the camera is not activated is set by the CPU 31 based on a user operation or the like. In addition, a PWM setting value for camera activation is set in advance in the PWM setting value register 33 at the time of imaging. FIG. 3 shows an example of setting the PWM set value. The settings 1, 2, and 3 in FIG. 3 are PWM setting values for when the camera is not activated, and are values according to the luminance level of the backlight. The setting at the time of camera activation is a PWM setting value that realizes a higher luminance than any one of the luminance levels 1, 2, and 3 when the camera is not activated.

  When there is no detection signal from the camera activation detection unit 12, the selection unit 21 of the luminance control unit 13 outputs the PWM setting value for the camera non-activation held in the PWM setting value register 32 to the PWM output unit 22. . On the other hand, when there is a detection signal from the camera activation detection unit 12, the PWM setting value for camera activation held in the PWM setting value register 33 during imaging is output to the PWM output unit 22.

  The PWM output unit 22 outputs a drive signal for the backlight LED 15 by PWM control in accordance with the PWM set value from the selection unit 21. FIG. 4 shows an output example of the drive signal of the backlight LED 15. In FIG. 4, the LED value is driven when the signal value is “0”, and the LED is not driven when the signal value is “1”. Therefore, the higher the ratio of the signal value “0”, the higher the luminance of the backlight. The settings 1, 2 and 3 in FIG. 4 and the camera start-up settings correspond to those in FIG. In the camera startup setting in FIG. 4, the ratio of the signal value “0” is larger than in any of the settings 1, 2, and 3, and the backlight luminance is the highest.

  According to the first embodiment described above, the brightness of the backlight increases when the camera is activated, so that the camera image displayed on the screen on the LCD becomes clear. Further, with the configuration of FIG. 2, the brightness of the backlight can be set to a predetermined value when the camera is activated.

FIG. 5 is a block diagram showing another configuration of the luminance control unit 13 and the luminance setting unit 14 of FIG.
In FIG. 5, the luminance setting unit 14 does not include the PWM setting value register 33 at the time of imaging, but includes an offset value register 41 and an adder 42 instead.
The offset value register 41 holds in advance the offset value of the PWM set value. This offset value is added by the adder 42 to the PWM setting value for when the camera is not started, held in the PWM setting value register 32. A value obtained by adding the offset value is output to the selection unit 21 as a PWM setting value for starting the camera.

  FIG. 6 shows an example of setting the offset value. The settings 1, 2, and 3 in FIG. 6 are PWM setting values for when the camera is not activated, and are values according to the luminance level of the backlight. A setting obtained by adding an offset value to the settings 1, 2, and 3 when the camera is not started becomes a setting for starting the camera.

  According to the configuration of FIG. 5 described above, the brightness of the backlight can be increased by a certain level when the camera is activated.

Next, a second embodiment will be described.
FIG. 7 is a block diagram showing the configuration of the mobile terminal device 1a according to the second embodiment of the present invention. A mobile terminal device 1a shown in FIG. 7 is a mobile terminal device with a wireless communication function, for example, a mobile phone. FIG. 7 shows only the configuration according to the present invention. Further, in FIG. 7, parts corresponding to the respective parts in FIG.

  In FIG. 7, a wireless unit 51 performs wireless communication with a wireless base station. The communication control unit 52 can be connected to, for example, the Internet via a wireless communication line and connected to a Web server. It is possible to acquire Web page data from the Web server. Data acquired by communication such as this Web page data can be input to the LCD screen display unit 17 and displayed on the screen. This display data includes text data or image data.

The communication control unit 52 outputs a communication connection detection signal to the luminance control unit 13 when connected to a Web server or the like via a wireless communication line. When there is no communication connection detection signal, the brightness control unit 13 drives the backlight LED 15 using the brightness setting value for non-communication connection (corresponding to the above-described PWM setting value for camera non-startup). . On the other hand, when there is a communication connection detection signal, the backlight LED 15 is driven using the luminance setting value for communication connection (corresponding to the above-described PWM setting value for starting the camera).
As a result, the brightness of the backlight increases during communication connection, so that the display data acquired by communication is clearly displayed on the LCD screen. For example, when the characters on the web page are small and the amount of characters is large, it is difficult to see if the screen is dark, but it becomes easier to see because the screen becomes brighter as the backlight brightness increases.

The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design changes and the like within a scope not departing from the gist of the present invention.
For example, the drive control method for the backlight LED is not limited to the PWM control described above. For example, a variable resistor may be used as the current limiting resistor, and the LED driving current may be controlled by selecting a resistance value corresponding to the brightness setting value.

It is a block diagram which shows the structure of the portable terminal device 1 which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structure of the brightness | luminance control part 13 and the brightness | luminance setting part 14 of FIG. It is a figure which shows the example of a setting of the PWM setting value which concerns on embodiment of this invention. It is a figure which shows the output example of the drive signal of LED15 for backlights concerning embodiment of this invention. It is a block diagram which shows the other structure of the brightness | luminance control part 13 and the brightness | luminance setting part 14 of FIG. It is a figure which shows the example of a setting of the offset value of FIG. It is a block diagram which shows the structure of the portable terminal device 1a which concerns on the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,1a ... Portable terminal device, 11 ... Camera, 12 ... Camera start detection part, 13 ... Luminance control part (luminance control means), 14 ... Luminance setting part (luminance control means), 15 ... Backlight LED, 17 ... LCD screen display unit, 21 ... selection unit, 22 ... PWM output unit, 31 ... CPU, 32 ... PWM setting value register, 33 ... PWM setting value register during imaging, 41 ... offset value register, 42 ... adder, 51 ... Wireless unit, 52... Communication control unit.

Claims (6)

In the backlight control device that controls the backlight of the display,
An imaging device for inputting an image to be displayed on the display;
Imaging device activation detection means for detecting activation of the imaging device;
Brightness setting means for setting the brightness of the backlight based on a user operation;
Brightness control means for controlling the brightness of the backlight,
When the backlight is driven according to the user-set brightness set by the brightness setting means, the brightness control means detects the start of the image pickup apparatus by the image pickup apparatus start detection means, The backlight control apparatus characterized by controlling the brightness of the backlight so that the brightness is higher than the brightness set by the user . In the backlight control device that controls the backlight of the display,
Communication means for acquiring and inputting display data to be displayed on the display by communication;
Communication connection detecting means for detecting a communication connection by the communication means;
Brightness setting means for setting the brightness of the backlight based on a user operation;
Brightness control means for controlling the brightness of the backlight,
When the backlight is driven in accordance with the user-set brightness set by the brightness setting means, the brightness control means detects the user connection when the communication connection detection means detects the communication connection. A backlight control apparatus , wherein the brightness of the backlight is controlled to be higher than the brightness of the backlight. The luminance setting means can set the luminance of the backlight based on the user operation from a plurality of luminance levels,
The brightness control means controls the brightness of the backlight so that the brightness becomes higher than any brightness according to the plurality of brightness levels . Backlight control device. A luminance offset value storage means for holding the luminance offset value;
The backlight control apparatus according to claim 1, wherein the luminance control unit increases the luminance by the luminance offset value. Display,
And the backlight of the display,
An imaging device for inputting an image to be displayed on the display;
An imaging device activation detection means for detecting that the imaging apparatus is started,
Brightness setting means for setting the brightness of the backlight based on a user operation;
Brightness control means for controlling the brightness of the backlight,
When the backlight is driven according to the user-set brightness set by the brightness setting means, the brightness control means detects the start of the image pickup apparatus by the image pickup apparatus start detection means, A backlight control device that controls the brightness of the backlight so that the brightness is higher than the brightness set by the user;
A portable terminal device comprising: Display,
And the backlight of the display,
A communication device for acquiring and inputting display data to be displayed on the display by communication;
Communication connection detecting means for detecting communication connection by the communication device;
Brightness setting means for setting the brightness of the backlight based on a user operation;
Brightness control means for controlling the brightness of the backlight,
When the backlight is driven in accordance with the user-set brightness set by the brightness setting means, the brightness control means detects the user connection when the communication connection detection means detects the communication connection. A backlight control device for controlling the brightness of the backlight so as to be higher than the brightness of
Mobile terminal apparatus comprising the.

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