TWI447697B - Hysteresis-type controlling method for backlight of portable electronic device - Google Patents

Description

Hysteresis backlight adjustment method for portable electronic device

The present invention relates to a backlight adjustment method for a portable electronic device, and more particularly to a hysteresis backlight adjustment method for a portable electronic device.

With the advancement of technology, more and more portable electronic devices such as mobile phones and personal digital assistants (PDAs) are becoming more and more powerful, and are gradually becoming popular for consumers. Furthermore, as the process of small and medium-sized LCD panels progresses and the price decreases, the probability and demand for users to view the LCD panel of the portable electronic device is also increasing.

In the display picture quality part of the portable electronic device liquid crystal panel (LCD), since the user may often use the portable electronic device in the action, the first thing is to improve the screen light source automatically according to different ambient light. To achieve energy saving and comfortable reading. If the external light source is too bright, the backlight is only a waste of power, so it automatically turns off, let the LCD reflect the light source by itself. However, when the ambient light is too dark, the display device is often brighter than the ambient light, so strong light will Causes discomfort to the user's eyes.

In general, the LCD can be transmissive and reflective, depending on the location of the source. The transmissive LCD is illuminated by a light source behind the screen, while viewing is on the other side of the screen (front). This type of LCD is often used in applications that require high brightness, such as computer monitors. Reflective LCDs, commonly found in electronic timepieces and PDAs, reflect the external light back from the rear reflecting surface to illuminate the screen. A transreflective LCD can be used both as a transmissive type and as a reflective type. When the external light is sufficient, the LCD works as a reflection type, and when the external light is insufficient, it can be used as a transmissive type.

Based on the above-mentioned deficiencies, a display having a brightness adjusting device may be developed, and the brightness adjusting device may include a light source sensing unit and a backlight adjusting unit. Referring to the first figure, the backlight brightness adjustment curve of the brightness adjusting device is assumed, and the display is a transflective LCD, and the ambient light brightness sensed by the light source sensing unit can be divided into three regions, respectively, by a critical value C1. And the weak light area, normal area and strong light area defined by C2. The backlight adjustment unit adjusts the backlight size according to the area in which the ambient light is located. However, in the above-described brightness adjusting device, if the user (for example, a person who uses the PDA to collect the parking fee) is in a moving state, the ambient light brightness may jump near the critical values C1 and C2, causing the backlight to change rapidly. This can cause the user to be visually exhausted and make the backlight adjustment unit work too frequently.

It is therefore an object of the present invention to provide a method of adjusting backlights in hysteresis to avoid bounce problems in backlight variations on portable electronic devices.

In order to achieve the above object, the present invention provides a hysteresis backlight adjustment method for a portable electronic device. After the portable electronic device is preset to operate in a preset mode and sense an ambient light brightness, the ambient light brightness is greater than A first threshold (eg, 2000 lumens) is set to operate the portable electronic device in a daylight mode. In the daylight mode, if the ambient light brightness is less than a second threshold (eg, 1000 lumens), the portable electronic device is set to operate in the preset mode. The first critical value is significantly greater than the second critical value, so that when the background light is sufficient, the backlight can be turned off to save power. Furthermore, the hysteresis backlight adjustment method prevents the backlight from rapidly changing between the normal mode and the daylight mode to prevent the user from viewing discomfort.

Furthermore, in the preset mode, if the ambient light brightness is less than a third threshold (eg, 100 lumens), the portable electronic device is set to operate in a night mode; and in the night mode, if the ambient light brightness is greater than And a fourth threshold (150 lumens), the portable electronic device is set to operate in the preset mode. The hysteresis backlight adjustment method prevents the backlight from rapidly changing between the normal mode and the night mode to prevent the user from viewing discomfort.

Referring to the second figure, a portable electronic device is operated according to the method of the present invention. The portable electronic device includes a controller 100, a light sensor 102, an analog digital converter 104, and a liquid crystal display ( The LCD) backlight driver 110, a button backlight unit 112, and an LCD 120.

The photo sensor 102 senses a background light brightness and sends the background light brightness to the analog to digital converter 104. The analog digital converter 104 converts the backlight brightness into a background light luminance digital value and sends it to the controller 100 for processing. The controller 100 is electrically connected to the LCD backlight driver 110 and the key backlight unit 112, respectively, for driving the LCD backlight driver 110 and the key backlight unit 112 according to the method of the present invention (described later in detail) and the background light luminance digital value. To control the LCD backlight and button backlight.

The LCD may be a transreflective LCD, such as the Casio Blanview LCD, but the scope of application of the method of the present invention is not limited thereto.

Referring to the third figure, a state diagram of a hysteresis backlight adjustment method for a portable electronic device according to the present invention. The preset operating mode of the portable electronic device of the present invention is a normal mode (S100), and when the brightness of the background light is greater than a first threshold LUX1, the controller 100 sets the portable electronic device in a daylight mode ( S110), wherein in the daylight mode, the controller 100 controls the LCD backlight driver 110 to be the minimum brightness, and controls the button backlight unit 112 to be the minimum brightness, for example, the minimum brightness may be zero.

In the daylight mode (S110), when the brightness of the backlight is less than a second threshold LUX2, the controller 100 sets the portable electronic device back to the normal mode (S100), and in the normal mode, the controller The LCD backlight driver 110 controls the user to preset the brightness, and controls the button backlight unit 112 to preset the brightness for the user. For example, the user preset brightness may be the maximum (100%) brightness. The aforementioned second threshold LUX2 is significantly smaller than the first threshold LUX1, for example, the first threshold LUX1 is 2000 lumens (as in daylight) and the second threshold LUX2 is 1000 lumens. Therefore, when the background light is sufficient, the backlight can be turned off, and the backlight is used as the light source, which saves power consumption of the portable electronic device. Furthermore, since the second threshold LUX2 is significantly different from the first threshold LUX1, the hysteresis effect of the backlight control can be provided, and the backlight can be quickly changed between the normal mode (S100) and the daylight mode (S110) to avoid use. Watch the discomfort.

In the normal mode (S100), and when the backlight brightness is less than a third threshold LUX3, the controller 100 sets the portable electronic device in the night mode (S120), wherein in the night mode, the control The controller 100 controls the LCD backlight driver 110 to have a small brightness, and controls the button backlight unit 112 to have a small brightness. For example, the small brightness may be 30% of the maximum brightness, so that the user can still be clear under weak light. See the LCD display content. In the night mode (S120), when the brightness of the background light is greater than a fourth threshold LUX4, the controller 100 sets the portable electronic device back to the normal mode (S100). The aforementioned third critical value LUX3 is significantly smaller than the fourth critical value LUX4, for example, the third critical value LUX3 is 100 lumens, and the fourth critical value LUX4 is 150 lumens. Therefore, the backlight is prevented from being rapidly changed between the normal mode (S100) and the night mode (S120) to prevent the user from viewing discomfort.

Referring to the fourth figure, for the backlight brightness adjustment curve of a portable electronic device operating according to the method of the present invention, it can be seen that the method of the present invention provides at least one hysteresis loop in the backlight brightness adjustment curve to enable the portable electronic The device does not have the problem of sharp and dark changes in the brightness of the background light. In addition, the user only needs to set the backlight setting in the normal mode (preset mode), so that the LCD screen of the portable electronic device can be clearly viewed in daylight, general brightness environment and nighttime, thereby greatly reducing the operation difficulty and improving. The ease of use of portable electronic devices.

In summary, it is known that the present invention has industrial applicability, novelty and advancement, and the structure of the present invention has not been seen in similar products and public use, and fully complies with the requirements of the invention patent application, and is filed according to the patent law.

[Practical]

C1, C2. . . Threshold

【this invention】

100. . . Controller

102. . . Light sensor

104. . . Analog digital converter

110. . . Liquid crystal display (LCD) backlight driver

112. . . Key backlight unit

120. . . LCD

S100-S120

The first figure is a backlight brightness adjustment curve of a conventional brightness adjusting device.

The second figure is a portable electronic device that operates in accordance with the method of the present invention.

The third figure is a state diagram of a hysteresis backlight adjustment method of the portable electronic device according to the present invention.

The fourth figure is a backlight brightness adjustment curve of a portable electronic device operating in accordance with the method of the present invention.

S100-S120

Claims (14)

A hysteresis backlight adjustment method for a portable electronic device, the portable electronic device having a light sensor, a liquid crystal display (LCD) backlight driver and a button backlight unit, the method comprising: using the light sensor Sensing an ambient light brightness; preset the portable electronic device to operate in a preset mode; setting the portable electronic device to operate in a daylight mode when the ambient light brightness is greater than a first threshold; When the ambient light brightness is less than a second threshold, the portable electronic device is set to operate in the preset mode, wherein the first threshold is greater than the second threshold to provide a backlight control hysteresis effect. The backlight of the portable electronic device in the daylight mode is less than the backlight brightness in the preset mode; in the preset mode, if the ambient light brightness is less than a third threshold, the portable mode is set. The electronic device is operated in a night mode; and in the night mode, if the ambient light brightness is greater than a fourth threshold, the portable electronic device is set to operate in the preset mode, wherein the Four-based threshold value is greater than the third threshold, the difference between the first threshold and the second threshold value is greater than the fourth threshold value and the difference between the third threshold value. The method of claim 1, wherein the first threshold is 2000 lumens and the second threshold is 1000 lumens. The method of claim 1, wherein the liquid crystal display backlight driver sets the backlight value to a maximum value. The method of claim 1, wherein the method is In the formula, the liquid crystal display backlight driver sets the backlight value to a minimum value. The method of claim 1, wherein in the preset mode, the button backlight unit sets the button backlight to a maximum value. The method of claim 1, wherein in the daylight mode, the button backlight unit sets the button backlight to a minimum value. The method of claim 1, wherein the difference between the first threshold and the second threshold is 1000 lumens, and the difference between the fourth threshold and the third threshold is 50 lumens. The method of claim 7, wherein the third threshold is 100 lumens and the fourth threshold is 150 lumens. The method of claim 7, wherein in the night mode, the liquid crystal display backlight driver sets the backlight value to 30% of the maximum value. The method of claim 7, wherein in the night mode, the button backlight unit sets the button backlight to 30% of the maximum value. The method of claim 1, wherein the LCD is a transflective LCD. The method of claim 1, wherein the portable electronic device is a personal assistant (PDA). The method of claim 1, wherein in the preset mode, the liquid crystal display backlight driver sets the backlight value to a user preset value. The method of claim 1, wherein in the preset mode, the button backlight unit sets the button backlight to a user preset value.