JP2006254304A - Portable terminal device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To cause a current that does not exceed maximum rating at a high temperature and obtains a sufficient display property at an ordinary temperature, to flow to an illuminator by controlling the current capable of flowing to the illuminator in accordance with an ambient temperature of a portable terminal device. <P>SOLUTION: The terminal device includes an illuminator for illuminating an information display screen 5 of the device or the information display screen and an operation input part; a light quantity detection means 1 for detecting the quantity of light around the terminal device; a temperature detection means 3 for detecting the ambient temperature of the terminal device; and dimming control means 7, 8 for adjusting the luminance of the information display screen by controlling a driving current of the illuminator based on information regarding the quantity of light detected by the light quantity detection means and information regarding the temperature detected by the temperature detection means. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention can control, for example, the illumination brightness of an illumination device for illuminating the information display unit to an optimum state in accordance with the surrounding environment in a portable terminal device including an information display unit such as a cellular phone. The present invention relates to the mobile terminal device.

As a conventional portable terminal device in which lighting devices such as a backlight and a key lighting device are automatically turned on and off at an appropriate timing according to the surrounding situation, for example, Japanese Patent Laid-Open No. 2002-171340 ( Hereinafter, it is referred to as Patent Document 1.
The dimming function of this conventional portable terminal device includes an illuminating device for illuminating the display surface of the information display device, and a light detecting means arranged at a position capable of detecting the brightness around the device main body. The illumination control unit is configured to control lighting and extinguishing of the lighting device based on the output signal of the light detection unit.

JP 2002-171340 A

In the dimming function provided in such a conventional portable terminal device, because it is a configuration that does not include control related to temperature, in order to protect the maximum rating of a lighting device such as a backlight, the maximum current that flows to the lighting device, It was necessary to set the value at a high temperature.
Therefore, even at room temperature at which further current can flow, the setting value is limited to a low value at high temperature, and sufficient current cannot be supplied to the lighting device. As a result, illumination is dark and has sufficient display characteristics. There was a problem that could not be obtained.

  The present invention was made to solve the above-described conventional problems, and the current that can be passed to the lighting device is adjusted according to the ambient temperature of the portable terminal device, so that the maximum rating is not exceeded at high temperatures and sufficient display at normal temperatures. An object of the present invention is to obtain a portable terminal device having a dimming function capable of flowing a current sufficient to obtain characteristics to the lighting device.

  A portable terminal device according to the present invention includes an information display unit of a portable terminal device, an illumination device for illuminating the information display unit and the operation input unit, a light amount detection unit that detects a light amount around the terminal device, Temperature detection means for detecting the ambient temperature of the terminal device, control of the drive current supplied to the illumination device based on the light quantity information detected by the light quantity detection means and the temperature information detected by the temperature detection means And a dimming control means for adjusting the illumination brightness of the illumination device.

  According to the present invention, the dimming control means is configured to control the driving current of the lighting device with reference to the output of the temperature detection means, so that the optimum lighting device operating condition can be set for the ambient temperature. It becomes possible, and the information display characteristic of a portable terminal device improves.

Embodiment 1 FIG.
Embodiment 1 of the present invention will be described with reference to FIGS.
FIG. 1 is a control block diagram showing the main configuration of Embodiment 1 of the present invention, and FIG. 2 is a diagram showing an example of the relationship between the peripheral light amount and the backlight current.
In FIG. 1, 1 is an optical sensor that detects the amount of ambient light, 2 is a light detection unit that receives the output of the optical sensor 1, and 3 is a temperature sensor that detects the ambient temperature. In this case, a certain temperature is detected. It has a threshold value and outputs a binary value that indicates whether the ambient temperature is above or below that temperature.
Reference numeral 4 denotes a temperature detection unit that receives the output of the temperature sensor 3. 5 is a display device for displaying information in the portable terminal device, 6 is an LED controller for supplying current to a backlight (not shown) for illuminating the display device 5, and 7 is for controlling the LED controller 6. The illumination control unit 8 is a dimming control circuit unit that determines the operation of the illumination control unit 7 based on information from the light detection unit 2 and the temperature detection unit 3. As shown in FIG. 2, the dimming control circuit unit 8 has a built-in profile in which the optimum backlight current with respect to the peripheral light quantity is set in two types at normal temperature and high temperature. Yes.

Next, the operation of the first embodiment will be described.
When the temperature detected by the temperature sensor 3 is at room temperature, the dimming control circuit unit 8 that detects the peripheral light amount by the optical sensor 1 has a built-in backlight according to the peripheral light amount at normal temperature. The LED controller 6 is instructed according to the current value profile.
As a result, the display device 5 can maintain optimum display characteristics with the luminance according to the peripheral light amount.

  In addition, when the temperature of the temperature sensor 3 exceeds a certain threshold, that is, at a high temperature, if the backlight current under normal temperature conditions is passed as it is, the maximum rating may be exceeded. 8 detects it and issues an instruction to the LED controller 6 according to another built-in high temperature profile. By doing so, it is possible to control the lighting so that the maximum rating of the display device 5 is not exceeded.

  As described above, according to the first embodiment of the present invention, the temperature detection means has the temperature sensor 3 having a binary output depending on the ambient temperature, and the dimming control means is the optimum of the lighting device for the ambient light amount. A first profile and a second profile in which the magnitudes of various driving currents are set in advance for two types at normal temperature and high temperature, and the dimming control means is provided according to the output of the temperature sensor. Is configured to control the driving current of the lighting device using the first profile or the second profile, so that it is possible to set the optimal lighting device operating condition with respect to the ambient temperature, and This has the effect of improving the information display characteristics.

Embodiment 2. FIG.
FIG. 3 is a control block diagram showing the main configuration of Embodiment 2 of the present invention, and FIG. 4 is a diagram showing the relationship between the peripheral light amount and the backlight current, and the relationship between the ambient temperature and the peak backlight current. is there.
3 differs from FIG. 1 of the first embodiment in that a temperature detector 9 such as a thermistor that outputs a continuous value according to a change in ambient temperature is used instead of the temperature sensor 3. Other configurations are the same as those in FIG.

In the second embodiment, as shown in FIG. 4, the profile of the profile incorporated in the dimming control circuit unit 8 is adjusted by adjusting the peak backlight current depending on the temperature, and what percentage of the peak backlight current depends on the amount of peripheral light. Two adjustments of whether to flow.
By doing so, it is possible to perform illumination control in which optimum display characteristics are continuously obtained with respect to changes in the ambient light amount and the ambient temperature.

Embodiment 3 FIG.
FIG. 5 is a control block diagram showing the main configuration of Embodiment 3 of the present invention. 1 denote the same or corresponding parts.
In the above-described first and second embodiments, the lighting control of the display device that displays the information of the mobile terminal device has been described. However, not only the display device 5 but also the operation input unit (operation key) as illustrated in FIG. It is also possible to perform illumination control of the brightness of the key backlight 10 at the same time.

It is a control block diagram which shows the main structures of the portable terminal device by Embodiment 1 of this invention. It is a figure which shows the relationship between the peripheral light quantity and backlight electric current in Embodiment 1 of this invention. It is a control block diagram which shows the main structures of Embodiment 2 of this invention. It is a figure which shows the relationship between the amount of ambient light and backlight current in Embodiment 2 of this invention, and the relationship between ambient temperature and a peak time backlight current. It is a control block diagram which shows the main structures of Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light sensor 2 Light detection part 3 Temperature sensor 4 Temperature detection part 5 Display apparatus 6 LED controller 7 Illumination control part 8 Dimming control circuit part 9 Temperature detector 10 Key backlight

Claims (3)

  Illumination device for illuminating the information display unit of the portable terminal device or the information display unit and the operation input unit, light amount detection means for detecting the amount of light around the terminal device, temperature for detecting the ambient temperature of the terminal device Based on the light quantity information detected by the detection means and the light quantity detection means and the temperature information detected by the temperature detection means, the dimming that controls the drive current of the illumination device and adjusts the luminance of the information display unit A mobile terminal device provided with a control means.   The temperature detection means has a temperature sensor having a binary output depending on the ambient temperature, and the dimming control means determines the optimum drive current magnitude of the illumination device with respect to the ambient light amount at room temperature and high temperature in advance. The first profile and the second profile set for the two types are incorporated, and the dimming control means uses the first profile or the second profile according to the output of the temperature sensor to 2. The portable terminal device according to claim 1, wherein a drive current of the device is controlled.   The temperature detection unit includes a temperature detector that outputs a continuous value according to a change in ambient temperature, and the dimming control unit adjusts the maximum current corresponding to the temperature of the driving current of the lighting device, and the ambient light amount. 2. The mobile terminal device according to claim 1, wherein the current value corresponding to the change in the current value is continuously adjusted.

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