Patent Application
20140160099
1. Field of the Invention
The present invention is directed to a display technique and more particularly, to a display technique for sunlight readable.
2. Description of Related Art
With the widespread popularization of liquid crystal displays (LCDs), requirements for functions of the LCDs have been gradually raised in many portable electronic products, especially in the portable electronic products, such as smart phones, personal digital assistants (PDAs), notebook computers (notebook PCs), tablet computers (tablet PCs) and so forth. These portable electronic products not only should be provided with good display effects indoors, but also should be maintained with the good display effects outdoors or in an environment with glaring light. Therefore, how to maintain the LCDs with good display effects in an environment with glaring light has become one of the most important trends in the LCD technique development.
Typically, when using a portable electronic product, the display content on the screen can not be clearly viewed once the portable electronic product is moved to a place under stronger sunlight. The main reason is that the sunlight outdoors has overly high brightness, and the sunlight directly irradiating on the screen is directly reflected by the screen surface, which results in the content displayed on the screen being unclearly visible by eyes. In one solution that is applied currently, the backlight brightness of the display is increased to generate less reflected light, such that the visibility of the display under glaring light is improved.
However, the aforementioned solution has to keep the brightness of the screen in a certain brightness level or higher to avoid the screen becoming darker relative to the glaring environment. Nevertheless, such solution is very power-consuming, and the user would experience eye irritation due to the overly bright screen. Therefore, in order to save power and enable images displayed on the portable electronic product to be clearly visible under various ambient light source conditions (including indoors and outdoors), development of a new display technique for sunlight readable is need.
Accordingly, the present invention is directed to a display method for sunlight readable and an electronic device using the same, which is capable of increase glare visibility for a display under to meet a condition of saving power.
The present invention is directed to a display method for sunlight readable, which is applicable to an electronic device having a display panel. The display method includes the following steps. An ambient light sensor value and image content are obtained. Next, a liquid crystal (LC) driving voltage is altered based on the ambient light sensor value and the image content, wherein the LC driving voltage is increasingly proportional to the ambient light sensor value and exceeds a normal operation driving voltage when the ambient light sensor value exceeds a high luminance value. Then, the display panel is drived under the LC driving voltage.
The present invention is further directed to an electronic device including an optical sensor, a display panel and a central processing unit (CPU). The optical sensor is configured to sense an ambient light sensor value. The display panel includes a LC driver IC. The CPU is coupled to the optical sensor and the display panel and is configured to alter a LC driving voltage based on the ambient light sensor value and image content. When the ambient light sensor value exceeds a high luminance value, the LC driving voltage is increasingly proportional to the ambient light sensor value and exceeds a normal operation driving voltage. The LC driver IC of the display panel is configured to drive the display panel under the LC driving voltage.
The present invention is still directed to an electronic device including an optical sensor, a display panel and a CPU. The optical sensor is configured to sense an ambient light sense value. The display panel includes a LC driver IC. The CPU is coupled to the optical sensor and the display panel and is configured to receive the ambient light sensor value, image content and an indication of an evoked application to generate a LC driving voltage setting. The CPU transmits the LC driving voltage setting to the LC driver IC of the display panel, and after the LC driver IC is adjusted according to the LC driving voltage setting, the LC driver IC performs an analog image process on the image content so as to display a sunlight readable image.
To sum up, in the display method for sunlight readable and the electronic device using the same disclosed by the present invention, by increasing the maximum LC driving voltage of the display panel and adjusting the gamma curve simultaneously, the transmittance of the display is improved. Thus, the overall brightness of the screen image is enhanced. The display panel still can be normally used even under the bright sunlight to achieve the power-saving effect.
In order to make the aforementioned and other features and advantages of the present invention more comprehensible, several embodiments accompanied with figures are described in detail below.
The accompanying drawings are included to provide a further understanding of the present invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention.
The optical sensor 110 is configured to sense ambient light sensor values of an environment where the electronic device 100 is located. The optical sensor 110 is, for example, a photo-diode, photo-transistor, a photosensitive resistor, any other element capable of generating a photo current or a detecting signal upon receiving light irradiation.
The CPU 120 is coupled to the optical sensor 110 and the display panel 130. The CPU 120 receives image content from source content and receives the ambient light sensor values from the optical sensor 110, such that the CPU 120 could alter a liquid crystal (LC) driving voltage based on the ambient light sensor value and the image content.
The display 130 is, for example, a liquid crystal display (LCD) including a driver IC 131. The driver IC 131 is capable of controlling a driving voltage applied on a liquid crystal (LC) molecule layer to change rotation angles of LC molecules by changing the driving voltage setting. Thereby, transmittance of the LCD is changed. It should be noticed that the driving voltage applied on the LCD is usually fixed in a normal operation driving voltage.
First, in step S210, an ambient light sensor value and image content are obtained in the CPU 120. Then, in step S220, a liquid crystal (LC) driving voltage is altered by the CPU 120 based on the ambient light sensor values and the image content. The LC driving voltage is increasingly proportional to the ambient light sensor value and exceeds a normal operation driving voltage when the ambient light sensor value exceeds a high luminance value. The LC driving voltage mentioned herein is referred to as the highest LC driving voltage which can be applied on the display panel 130. The LC driving voltage may be used to adjust parameter Y of the display panel 130, wherein the parameter Y in the xyY color space is defined by the Commission Internationale de l'Eclairage (CIE) and represents brightness of colors. In other words, the higher the LC driving voltage is, the higher the transmittance of the display panel is. Then, in step S230, the display panel 130 is drived under the LC driving voltage set by the CPU 120.
Another embodiment of the present invention will be illustrated hereinafter. The labeled elements and a part of content of the preceding embodiment are followed in the present embodiment, in which the same elements are given the same or similar reference symbols, and the description regarding the same technique content is eliminated.
The CPU 120 includes a display profile 421 and a source content 422. The image content is directly transmitted from the source content 422 to the display profile 421 to enable the display profile 421 to analyze detailed information of the image, such as a graylevel ratio, a contrast ratio, a portion of black point and white point, and RGB pixels. The display profile 421 is configured to analyze the image content to be displayed on the display panel 130 and generates a gamma curve setting based on the image content. The driver IC 131 of the display panel 130 of the electronic device 400 includes an analog gamma register 432. The analog gamma register 432 is configured to perform an analog image process on the image content according to the gamma curve setting, so as to display a sunlight readable image on the display panel 130.
First, in step S510, ambient light sensor values and image content are obtained in the display profile 421 of the CPU 120. Then, in the step S520, the image content to be displayed on the display panel 130 is analyzed by the display profile 421 and a gamma curve setting is generated based on the image content.
Specifically, when the image content is determined as a dialing image, a mail image, or an image having a large portion of black point, white point, or a combination thereof, the display profile 421 generates the gamma curve setting representing a high contrast response. When the image content is determined as a picture image, a video image, an image having a large portion of color profile or a combination thereof, the display profile 421 generates the gamma curve setting representing a gamma curve with increased transmittance in middle and low graylevel range.
In step S530, the LC driving voltage is altered by the CPU 120 based on the ambient light sensor values and the image content. The LC driving voltage is increasingly proportional to the ambient light sensor value and exceeds a normal operation driving voltage when the ambient light sensor value exceeds a high luminance value.
Finally, in step S540, the display panel 130 is drived, under the LC driving voltage, based on the gamma curve setting. Specifically, image content to be displayed and the LC driving voltage setting are outputted from the display profile 421 to the driver IC 131 of the display panel 130 through a data stream d1 and a data stream d2 respectively. Besides, the gamma curve setting is transmitted from the display profile 421 to the analog gamma register 432 of the display panel 130 through a data stream d3. Here, the gamma curve setting is a digital signal which is configured to control the analog gamma register 432 in the driver IC 131. Different gamma curve setting represent different gamma curve. That is, after adjusting the LC transmittance of the display panel 130 according to the LC driving voltage and performing an analog image process on the image content, a sunlight readable image is displayed on the display panel 130.
Hereinafter, one more embodiment of the present invention is illustrated.
Referring to
The ambient light detector 723 is configured to receive a signal (e.g. a voltage signal or a current signal) outputted from the optical sensor 110 so as to determine illumination intensity (unit: lux) sensed by the optical sensor 110. After the ambient light detector 723 transmits the illumination intensity of an ambient light source to the display profile 421, the display profile 421 may further perform classifying according to degrees of illumination intensity so as to generate the ambient light level information.
The application indicator 724 is coupled to the display profile 421. When an application is evoked, the application indicator 724 generates an indication of the application to the display profile 421, such that the display profile 421 analyzes the image content based on the indication of the application. The source content 124 may transmit the image content to the frame buffer 725 for temporary storage, such that the display profile 421 may read the image content as desired from the frame buffer 125 at any time.
First, the image content from the source content 422 and the illumination intensity from the ambient light detector 723 are received in the display profile 421 of the CPU 120, such that the ambient light level information is generated accordingly. Besides, an indication of an evoked application generated form the application indicator 724 is received (step S810).
Next, the image content to be displayed on the display panel 130 is analyzed by the display profile 421 and a gamma curve setting and a saturation/hue setting are generated based on the image content and the indication of the application. Specifically, color parameters of the image content, such as black-and-white (B & W) ratio, hue, saturation, are directly analyzed in the display profile 421, such that a saturation/hue setting is generated. In addition, the gamma curve setting is generated in the display profile 421 according to the illumination intensity and the indication of the application (step S820). And a LC driving voltage is altered based on the illumination intensity, the image content and the indication of the application (step S830).
Referring to Table 1 as below, Table 1 illustrates the relationship between the ambient light level information and the aforementioned setting.
Referring to Table 1, according to illumination intensity degrees, ambient light source levels may be classified into five types by the display profile 421. The adjustment on the LC driving voltage setting and the gamma curve setting are decided according to the ambient light source levels. Besides, in the portion of the gamma curve setting, the indication of the application may also be added in for further consideration. Referring to Table 2, Table 2 illustrates the relationship between the indication of the application and the aforementioned settings.
With reference to Table 2, the indication of the application represents a type of application program that is being executed by the electronic device 700. For example, the application program that is being executed may be classified into types, such as a gallery mode, a camera mode, a file mode or any other mode. Therein, the file mode may be, for example, an application program executing a dialing program, email or e-book, where more text information is presented. Since the display panel for the application program presenting a large portion of black point, white point, or a combination thereof has to be maintained in a high contrast ratio of white on black or black on white in an image screen with, the transmittance of the part having lower graylevel is not required to be enhanced.
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Further, it is to be mentioned that in the present embodiment, not only the transmittance of the display panel is enhanced by adjusting the LC driving voltage and the gamma curve setting, whether the ambient light source level is greater than a default brightness level is further determined by the CPU 120. If true, a brightness setting is generated and transmitted to a LED backlight module (not shown) coupled to the display panel such that backlight brightness of the display is enhanced. For example, the default brightness level is the 5th level as shown in Table 1. When the ambient light source level is the 5th level, the electronic device 700 may increase the LC transmittance by enhancing the greatest LC driving voltage, adjusting the gamma curve and enhancing the brightness of the backlight source when. Thereby, the electronic device 700 can still be used normally under the bright sunlight.
Based on the above, in the present invention, only when the ambient light source level is greater than the default light source level, the backlight source is increased for enhancing the brightness of the display panel. Otherwise, when the ambient light source level is not greater than the default light source level, the transmittance of the display is enhanced by increasing the LC driving voltage and adjusting the gamma curve. Accordingly, not only the power-saving effect can be achieved, but also the display can be sunlight readable under various conditions of the ambient light source.
Although the invention has been described with reference to the above embodiments, it will be apparent to one of the ordinary skill in the art that modifications to the described embodiment may be made without departing from the spirit of the invention. Accordingly, the scope of the invention will be defined by the attached claims not by the above detailed descriptions.
