Display device and display control method

A display device and a display control method are provided. The display device is applicable to a display panel. The display device includes a display driver integrated circuit (IC), a gate driver in panel (GIP) circuit and a GIP check circuit. The GIP circuit includes a plurality of shift registers connected in series, and the shift registers may generate a plurality of gate driving signals to control operations of a plurality of rows of display units within the display panel, respectively. The GIP check circuit may sequentially check whether a plurality of specific gate driving signals among the gate driving signals are available. The display driver IC may generate a check result according to at least one signal from the display panel, and selectively adjust display data corresponding to an image to make the display panel display an adjusted image according to the check result.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention is related to display control, and more particularly, to a display device and a display control method applicable to the display device.

2. Description of the Prior Art

Liquid crystal display (LCD) panels are popular in various applications such as automotive display panels. A conventional display driver integrated circuit (IC) has no specific solution to deal with the problem of gate driving mechanism malfunction of a display panel, and may therefore introduce some traffic risks. In some situations, the display panel is not completely damaged, for example, a portion of might still work. Thus, there is a need for a novel method and architecture, to properly utilize the portion of gate driving mechanism that is not damaged for improving safety of an automobile driver.

SUMMARY OF THE INVENTION

This in mind, an objective of the present invention is to provide a display device and a display control method applicable to the display device, which can utilize the portion of gate driving mechanism that is not damaged as much as possible, in order to improve safety of a driver and passenger(s) on an automobile.

At least one embodiment of the present invention provides a display device, where the display device is applicable to a display panel configured to display an image. The display device may comprise a display panel and a display driver integrated circuit (IC) coupled to the display panel. The display device may further comprise a gate driver in panel (GIP) circuit and a GIP check circuit, where the GIP circuit is coupled to the display panel, and the GIP check circuit is coupled to the GIP circuit. The GIP circuit may comprise a plurality of shift registers connected in series, and the shift registers are configured to generate a plurality of gate driving signals to control operations of a plurality of rows of display units within a display active area of the display panel, respectively. The GIP check circuit may be configured to sequentially check whether a plurality of specific gate driving signals among the gate driving signals are available, and accordingly generate a check signal. The display driver IC may be configured to generate a check result according to the check signal or at least one of the gate driving signals, and selectively adjust display data corresponding to the image to make the display panel display an adjusted image in an available area of the display active area according to the check result.

At least one embodiment of the present invention provides a display control method, where the display control method is applicable to a display device. The method may comprise: utilizing a plurality of shift registers connected in series within a GIP circuit of the display device to generate a plurality of gate driving signals, respectively, wherein the gate driving signals are configured to control operations of a plurality of rows of display units within a display active area of the display panel, respectively; utilizing a GIP check circuit of the display device to sequentially check whether a plurality of specific gate driving signals among the gate driving signals are available, and accordingly generating a check signal; utilizing a display driver IC of the display device to generate a check result according to the check signal or at least one of the gate driving signals, and selectively adjusting display data corresponding to an image to make the display panel display an adjusted image in an available area of the display active area according to the check result.

The display device and the display control method provided by embodiments of the present invention can roughly determine damage condition of a display panel of the display device, and accordingly adjust display data corresponding to an image in order to utilize an available area of the display panel as much as possible when the display panel is partially damaged. Thus, the present invention can enhance safety of a driver and passenger(s) on the automobile without introducing any side effects or in a way that is less likely to introduce side effects.

DETAILED DESCRIPTION

FIG. 1is a diagram illustrating a display device10according to an embodiment of the present invention. The display device10is applicable to a display panel (e.g. a display panel110shown inFIG. 1) of a dashboard of an automobile, which may display an image showing driving status (e.g. speed, oil volume, etc.) and some safety instructions, but the present invention is not limited thereto. The display device10may comprises a display driver integrated circuit (IC)200, where the display driver IC200is coupled to the display panel110. The display device10may further comprise a gate driver in panel (GIP) circuit120and a GIP check circuit130, where the display panel110, the GIP circuit120and the GIP check circuit130may be manufactured by a same process such as a Thin-Film Transistor (TFT) process, more particularly, may be built on a glass plate100. In some embodiments, the display panel110is not comprised in the display device10; in other embodiments, the display device10may comprise the display panel110; but the present invention is not limited thereto. As shown inFIG. 1, the GIP circuit120is coupled to the display panel110, and the GIP check circuit130is coupled to the GIP circuit120. In this embodiment, the display driver IC200may output display data corresponding to an image (which may comprise information related to the aforementioned driving status and safety instructions) to the display panel110(more particularly, to a display active area of the display panel110), and the display panel110(more particularly, the display active area of the display panel110) may display the image accordingly. The image without any adjustment is referred to as an image ORG for better comprehension.

FIG. 2is a diagram illustrating the GIP circuit120according to an embodiment of the present invention. As shown inFIG. 2, the GIP circuit120may comprise a plurality of shift registers (e.g. flip-flops) connected in series, such as shift registers121,122,123,124,125,126,127,128and129, and the shift registers may generate a plurality of gate driving signals to control operations of a plurality of rows of display units within the display active area of the display panel110shown inFIG. 1, respectively. In particular, each of the shift registers121,122,123,124,125,126,127,128and129may be synchronized with a clock signal CKV (e.g. a pair of clock signals with opposite logic levels respectively). For example, the shift register121may be triggered by a start pulse signal STV and thereby generate a high pulse on a gate driving signal (e.g. an output signal GOUT1) among the gate driving signals; the shift register122may be triggered by the output signal GOUT1and thereby generate a high pulse on a gate driving signal (e.g. an output signal GOUT2) among the gate driving signals; the shift register123may be triggered by the output signal GOUT2and thereby generate a high pulse on a gate driving signal (e.g. an output signal GOUT3) among the gate driving signals; the shift register124may be triggered by the output signal GOUT3and thereby generate a high pulse on a gate driving signal (e.g. an output signal GOUT4) among the gate driving signals; the shift register125may be triggered by the output signal GOUT4and thereby generate a high pulse on a gate driving signal (e.g. an output signal GOUT5) among the gate driving signals; the shift register126may be triggered by the output signal GOUT5and thereby generate a high pulse on a gate driving signal (e.g. an output signal GOUT6) among the gate driving signals; the shift register127may be triggered by the output signal GOUT6and thereby generate a high pulse on a gate driving signal (e.g. an output signal GOUT7) among the gate driving signals; the shift register128may be triggered by the output signal GOUT7and thereby generate a high pulse on a gate driving signal (e.g. an output signal GOUT8) among the gate driving signals; and the shift register129may be triggered by the output signal GOUT8and thereby generate a high pulse on a gate driving signal (e.g. an output signal GOUT9) among the gate driving signals. As shown inFIG. 2, the output signals GOUT1, GOUT2, GOUT3, GOUT4, GOUT5, GOUT6, GOUT7, GOUT8and GOUT9may sequentially have a high pulse (e.g. a pulse with logic value “1”) which is shifted stage by stage as shown inFIG. 2, in order to sequentially enable respective rows of display units within the display panel110. It should be noted that the number of shift registers shown in FIG.2is for illustrative purpose only, and is not a limitation of the present invention. For example, the number of shift registers may be determined according to display resolution of the display panel110, and operations of a GIP circuit with a different number of shift registers may be deduced by analogy.

FIG. 3illustrates a condition where one or more shift registers within the GIP circuit120shown inFIG. 2are damaged. As shown inFIG. 3, when the shift registers126and127are damaged, the shifting operation of the high pulse is stopped at the damaged shift register such as the shift register126, and the output signals GOUT6, GOUT7, GOUT8and GOUT9is therefore unavailable even though the shift registers128and129are not damaged. The shift registers121,122,123,124and125still work, however. Under this condition, a portion of the display active area of the display panel110is unavailable, but another portion of the display active area of the display panel110might be still available. The display device10shown inFIG. 1can enable an associated mechanism to utilize the available portion of the display active area as much as possible, in order to allow a user to at least obtain certain information (e.g. information related to the aforementioned safety instructions), and thereby guarantee safety of the driver and any other passenger of the automobile.

In this embodiment, the display active area of the display panel110may be divided into partitions by connecting output terminals of a plurality of specific shift registers among the shift registers (e.g. some of the shift registers121to129as shown inFIG. 2) to the GIP check circuit130. The GIP check circuit130shown inFIG. 1may sequentially check whether a plurality of specific gate driving signals among the gate driving signals generated are available, and accordingly generate a check signal VTCS. For example, the specific gate driving signals may be a plurality of predetermined gate driving signals among the plurality of gate driving signals, such as some gate driving signals of some predetermined shift registers among the plurality of shift registers, where the predetermined shift registers may be selected in advance in a design or production phase according to a predetermined rule, but the present invention is not limited thereto. As shown inFIG. 1, the GIP check circuit130may comprise a check signal terminal such as a terminal TCS coupled to the display driver IC200(e.g. a terminal GDETL of the display driver IC200) to transmit the check signal VTCS to the display driver IC200, and may further comprise a plurality of switches such as switches SW1, SW2and SW3, where the switches SW1, SW2and SW3may be coupled between the terminal TCS and the specific shift registers. For example, the switch SW1may be coupled between the terminal TCS and an output terminal (which outputting the signal GOUT3) of the shift register123, the switch SW2may be coupled between the terminal TCS and an output terminal (which outputting the signal GOUT5) of the shift register125, and the switch SW3may be coupled between the terminal TCS and an output terminal (which outputting the signal GOUT7) of the shift register127, where the shift registers123,125and127may represents the specific shift registers, but the present invention is not limited thereto. In addition, an output terminal of a last shift register that is farthest from the display driver IC200along an associated input signal path of the last shift register among the shift registers (e.g. the shift register129among the shift registers121to129) may be coupled to the display driver200(e.g. a terminal GDETL of the display driver200). In this embodiment, the GIP circuit120and the GIP check circuit130are positioned on different sides of the display panel110(e.g. the GIP circuit120is positioned on the right side of the display panel110and the GIP check circuit130is positioned on the left side of the display panel110as shown inFIG. 1); and in some embodiments, the GIP circuit120and the GIP check circuit130may be positioned on a same side of the display panel110; but the present invention is not limited thereto.

FIG. 4is a diagram illustrating detailed implementation of the display device10shown inFIG. 1according to an embodiment of the present invention. As shown inFIG. 4, the display driver IC200may comprise a timing controller (TCON)210and a scaling circuit220, where the TCON210is configured to control operations of the display driver IC200(e.g. respective components within the display driver IC200), and the scaling circuit220is configured to process the display data (e.g. display data DATA0) corresponding to the image ORG from the TCON210to generate adjusted display data (e.g. display data DATAS) when needed. In addition, the display driver IC200may further comprise an on-screen display (OSD) circuit230, a source output circuit240, a partition GIP detection circuit250, a GIP control circuit260and a GIP detection circuit270. In this embodiment, the scaling circuit220, the OSD circuit230, the partition GIP detection circuit250, the GIP control circuit260and the GIP detection circuit270are coupled to the TCON210, and the source output circuit240is coupled to the scaling circuit220and the OSD circuit230.

In this embodiment, the GIP control circuit260of the display driver IC200may transmit a start pulse such as a high pulse of the start pulse signal STV through at least one portion of terminals GOUTR[20:1] of the display driver IC, to trigger a first shift register (e.g. the shift register121shown inFIG. 2) that is nearest to the display driver IC200along the serial connection path (e.g. the associated input signal path of the last shift register) among the shift registers within the GIP circuit120of the display device10, and the output terminal of the last shift register (referred to as the shift register12X_LAST hereinafter) that is farthest from the display driver IC200along the associated input signal path of the last shift register among the shift registers within the GIP circuit120of the display device10is coupled to the GIP detection circuit270of the display driver IC200through the terminal GDETR shown inFIG. 1. In this embodiment, the GIP detection circuit270may generate a preliminary result RESULT1according to an output signal GOUT_LAST from the shift register12X_LAST (e.g. check whether the output signal GOUT_LAST has the aforementioned high pulse, to generate the preliminary result RESULT1). For example, when the preliminary result indicates that the output signal GOUT_LAST is available, it means all shift registers within the GIP circuit120operate normally, the display driver IC200may prevent adjusting the display data and control the source output circuit240to output the display data to the display active area of the display panel110directly, to make the display panel110display the image ORG without adjustment. In another example, when the preliminary result indicates that the output signal GOUT_LAST is unavailable, it means at least one shift register within the GIP circuit120operates abnormally (e.g. being damaged), the display driver IC200may enable a detection flow to roughly find out which register (or which partial structure circuit in the display active area of the display panel110, such as a gate line electrically connected to the output of a certain switch) is damaged, in order to determine which partition of the display active area of the display panel110is still available.

In this embodiment, the TCON210may control the partition GIP detection circuit250to output signals VSW1, VSW2and VSW3through at least one portion of terminals GOUTL[20:1] of the display driver IC200for respectively controlling the switches SW1, SW2and SW3shown inFIG. 1, respectively.FIG. 5is a timing diagram illustrating some signals (e.g. signals VSYNC, DE, VSW1, VSW2and VSW3) related to the detection flow according to an embodiment of the present invention, where the signal VSYNC is utilized for synchronization of the signals DE, VSW1, VSW2and VSW3, and a high level (e.g. the logic value “1”) of the signal DE means the detection flow is enabled. For example, the signal VSYNC may be a vertical synchronization signal for performing vertical synchronization of the display panel110, where one vertical synchronization period of the vertical synchronization signal comprises three enablement periods respectively belonging to the signals VSW1, VSW2and VSW3, and an enablement period of the signal DE starts from the enablement period of the signal VSW1and ends at the enablement period of the signal VSW3, but the present invention is not limited thereto. For better comprehension, please refer toFIG. 5in conjunction withFIG. 1, and take the GIP circuit120having the shift registers121to129shown inFIG. 2as an example. Assume that the switch SW1is coupled between the terminal TCS and the output terminal of the shift register123, the switch SW2is coupled between the terminal TCS and the output terminal of the shift register125, and the switch SW3is be coupled between the terminal TCS and the output terminal of the shift register127. The GIP check circuit130may generate the check signal VTCS on the check signal terminal TCS by sequentially transmitting the output signals GOUT3, GOUT5and GOUT7during periods of turning on the switches SW1, SW2and SW3, respectively, and the partition GIP detection circuit250may generate a final result RESULT2according to the check signal VTCS (e.g. check whether each of the output signals GOUT3, GOUT5and GOUT7has the aforementioned high pulse, to generate the final result RESULT2). For example, when the final result RESULT2indicates that the output signals GOUT3, GOUT5and GOUT7are available, it means at least the shift registers121to127are not damaged, and therefore rows of display units controlled by the shift registers121to127are still available even though at least one of the shift registers128and129is damaged. In another example, when the final result RESULT2indicates that the output signals GOUT3and GOUT5are available and the output signal GOUT7is unavailable, it means at least the shift registers121to125are not damaged, and therefore rows of display units controlled by the shift registers121to125are still available even though at least one of the shift registers126and127is damaged. In yet another example, when the final result RESULT2indicates that the output signal GOUT3is available and the output signals GOUT5and GOUT7are unavailable, it means at least the shift registers121to123are not damaged, and therefore rows of display units controlled by the shift registers121to123are still available even though at least one of the shift registers124and125is damaged. In yet another example, when the final result RESULT2indicates that the output signals GOUT3, GOUT5and GOUT7are unavailable, it means at least one of the shift registers121to123is damaged, and the display device10(e.g. the shift registers121to123therein) is too damaged to allow the display panel110to completely shows information included in the image ORG.

As mentioned above, the TCON210can determine which partition of the display active area of the display panel110is still available according to a check result (e.g. the preliminary result RESULT1and/or the final result RESULT2), and the TCON210may accordingly control the source output circuit240to transmit corresponding display data to make the display panel110display a corresponding image which includes as much information of the image ORG as possible in an available area of the display active area of the display panel110. In this embodiment, the available area may represents an area that is capable of displaying the corresponding image. In particularly, the display driver IC200may to generate a check result (e.g. the preliminary result RESULT1and/or the final result RESULT2) according to the check signal VTCS or the output signal GOUT_LAST, and selectively adjust the display data corresponding to the image ORG to make the display panel110display an adjusted image in the available area of the display active area of the display panel110according to the check result.

FIG. 6illustrates the display device10shown inFIG. 1applied to an automobile display panel according to an embodiment of the present invention. As mentioned above, when the preliminary result RESULT1indicates that the output signal GOUT_LAST is available, the display driver IC200may prevent adjusting the display data, to make the display panel display the image ORG without adjustment.

FIG. 7illustrates a control scheme of the display device10shown inFIG. 1according to an embodiment of the present invention, where display control associated with the detection flow is disabled. When the GIP circuit120of the display device10partially malfunctions, the preliminary result RESULT1may indicate that the output signal GOUT_LAST is unavailable. As the display control associated with the detection flow is disabled, a driver of the automobile may miss certain information such as messages “DO NOT STEP ON THE BRAKE”, “HOLD THE STEERING WHEEL” of the image ORG as shown inFIG. 7, and may impact the driving safety.

FIG. 8illustrates a control scheme of the display device10shown inFIG. 1according to another embodiment of the present invention, where the display control associated with the detection flow is enabled. When the GIP circuit120of the display device10partially malfunctions, the preliminary result RESULT1may indicate that the output signal GOUT_LAST is unavailable. The display driver IC200may adjust the display data to make the display panel110display the adjusted image in the available area of the display active area of the display panel110according to the check result (e.g. the preliminary result RESULT1and the final result RESULT2), wherein the available area is smaller than the display panel (e.g. the display active area of the display panel110) in this control scheme. In particular, when the check result (e.g. the preliminary result RESULT1and the final result RESULT2) indicates that a portion of the specific gate driving signals are available and the rest are unavailable (e.g. the gate driving signals transmitted from the shift registers coupled to the switches SW1and SW2are available and the gate driving signal transmitted from the shift register coupled to the switch SW3is unavailable), the display driver IC200(e.g. the source output circuit240therein shown inFIG. 4) may outputs the adjusted display data generated by the scaling circuit220shown inFIG. 4to make the display panel110display a scaled version SCL of the image ORG in the available area as shown inFIG. 8. Regarding other conditions (e.g. a condition where the gate driving signals transmitted from the shift registers coupled to the switches SW1, SW2and SW3are available and the GOUT_LAST is unavailable, and a condition where the gate driving signal transmitted from the shift register coupled to the switch SW1is available and the gate driving signals transmitted from the shift registers coupled to the switches SW2and SW3are unavailable), the available area of the display active area of the display panel110may be different, and the scaled version of the image ORG may vary accordingly. Those skilled in the art should understand the display control regarding these conditions according to the above descriptions, related detail similar to this embodiment is not repeated for brevity.

FIG. 9illustrates a control scheme of the display device10shown inFIG. 1according to an embodiment of the present invention, where the display control associated with the detection flow is disabled. As shown inFIG. 9, the GIP circuit120of the display device10severely malfunctions, and a great portion of the display active area of the display panel110is unavailable.FIG. 10illustrates a control scheme of the display device10shown inFIG. 1according to another embodiment of the present invention, where the display control associated with the detection flow is enabled. When the check result (e.g. the final result RESULT2) indicates that all gate driving signals transmitted from the shift registers coupled to the switches SW1, SW2and SW3are unavailable, the display driver IC200may enable a teletext OSD function and output default display data (e.g. display data DATAOSD generated by the OSD circuit230shown inFIG. 4) corresponding to a default image which merely shows OSD icons OSD_ICON, to make the display panel110display the default image in a default area, and the default area is positioned on one or more display units (e.g. one or more rows of display units) that are nearest to the display driver IC200along one or more associated data signal paths of the one or more display units among the plurality of rows of display units as shown inFIG. 10.

FIG. 11is a working flow illustrating a display control method according to an embodiment of the present invention, where the display control method is applicable to a display device (e.g. the display device10shown inFIG. 1). It should be noted that the working flow shown inFIG. 11is for illustrative purposes only, but is not a limitation of the present invention. One or more steps may be added, deleted or modified in the working flow shown inFIG. 11. In addition, if a same result may be obtained, these steps do not have to be executed in the exact order shown inFIG. 11.

In Step S110, the display device may utilize a plurality of shift registers connected in series within a GIP circuit of the display device to generate a plurality of gate driving signals, respectively, where the gate driving signals are configured to control operations of a plurality of rows of display units within a display active area of a display panel (e.g. the display device110shown inFIG. 1), respectively.

In Step S120, the display device may utilize a GIP check circuit of the display device to sequentially check whether a plurality of specific gate driving signals among the gate driving signals are available, and accordingly generate a check signal.

In Step S130, the display device may utilize a display driver IC of the display device to generate a check result according to the check signal or at least one of the gate driving signals, and selectively adjust display data corresponding to an image to make the display panel display an adjusted image in an available area of the display active area according to the check result.

FIG. 12illustrates detailed implementation of the working flow shown inFIG. 11according to an embodiment of the present invention. For better comprehension, please refer toFIG. 12in conjunction withFIG. 1andFIG. 4.

In Step S210, the display device may check whether a signal (e.g. the signal GOUT_LAST) received by the terminal GDETR is normal or available (labeled “GDETR is normal?” inFIG. 12for brevity). If the determination is “Yes”, the display device normally displays the image without adjustment, and the flow returns Step S210; if the determination is “No”, the flow enters Step S220.

In Step S220, the display device may report an error to a host device (e.g. the TCON210) and enable a GIP error detection mechanism.

In Step S230, the display device may turn on the switch SW1and check whether a signal received by the terminal GDETL is normal or available (labeled “SW1is turned on, GDETL is normal?” inFIG. 12for brevity). If the determination is “Yes”, the flow enters Step S240; if the determination is “No”, it means the display panel or the display device is severely damaged, and the flow enters Step S290.

In Step S240, the display device may turn on the switch SW2and check whether the signal received by the terminal GDETL is normal or available (labeled “SW2is turned on, GDETL is normal?” inFIG. 12for brevity). If the determination is “Yes”, the flow enters Step S250; if the determination is “No”, it means the display panel or the display device is partially damaged, and the flow enters Step S280.

In Step S250, the display device may turn on the switch SW3and check whether the signal received by the terminal GDETL is normal or available (labeled “SW3is turned on, GDETL is normal?” inFIG. 12for brevity). If the determination is “Yes”, it means the display panel or the display device is slightly damaged, the flow enters Step S260; if the determination is “No”, it means the display panel or the display device is partially damaged, and the flow enters Step S270.

In Step S260, the display device scales down the image by a first ratio such as four fifths and proceeds to display a scaled image as the display panel or the display device is slightly damaged (labeled “Panel is slightly damaged, scale to ⅘, proceed to display image” inFIG. 12for brevity).

In Step S270, the display device scales down the image by a second ratio such as two thirds and proceeds to display a scaled image as the display panel or the display device is partially damaged (labeled “Panel is partially damaged, scale to ⅔, proceed to display image” inFIG. 12for brevity).

In Step S280, the display device scales down the image by a third ratio such as one third and proceeds to display a scaled image as the display panel or the display device is partially damaged (labeled “Panel is partially damaged, scale to ⅓, proceed to display image” inFIG. 12for brevity).

In Step S290, the display device enable OSD display as the display panel or the display device is severely damaged (labeled “Panel severely damaged, enable OSD display” inFIG. 12for brevity).

In the above embodiments, the display driver IC200may generate the preliminary result RESULT1first, and then selectively enable the GIP error detection mechanism (e.g. one or more steps of S220to S290) according to the preliminary result RESULT1. If the preliminary result RESULT1indicates that the display panel or the display device is not damaged at all (e.g. the determination of Step S210is “Yes”), subsequent steps related to the GIP error detection mechanism can be omitted, but the present invention is not limited thereto.

In some embodiments, the step of generating the preliminary result RESULT1may be omitted, and the GIP error detection mechanism may be always enabled. For example, a signal path from the shift register12X_LAST within the GIP circuit120to the terminal GDETR of the display driver IC200shown inFIG. 1and/or the GIP detection circuit270shown inFIG. 4may be omitted. Under this configuration, the GIP check circuit130may further comprise another switch SWX coupled between the check signal terminal TCS and the shift register12X_LAST, in order to check whether the whole display active area of the display panel110is available, but the present invention is not limited for brevity, where control method of the switch SWX is similar to that of the switches SW1, SW2and SW3, and is not repeated here for brevity. For example, when the final result RESULT2generated by the partition GIP detection circuit250shown inFIG. 4indicates that the signal GOUT_LAST is available, the display driver IC200may prevent adjusting the display data, to make the display panel110display the image without adjustment. According to this architecture, the detailed implementation of the working flow shown inFIG. 12may be modified; for example, Step S210may be removed, and another step related to the SWX and the signal GOUT_LAST may be added.

Briefly summarized, the display device and the display control method provided by the embodiments of the present invention can roughly determine which partition of a display active area of the display device is surely available, and then according scaled an original image in order to display a scaled image without missing important information included in the original image. Furthermore, if the display device such as a display panel thereof is too damaged to display the scaled image, the display device may merely display OSD icons, which can notify a user (e.g. a driver of an automobile equipped with this display device) that the display panel need to be fixed. Thus, the present invention can enhance safety of a driver and passenger(s) on the automobile without introducing any side effects or in a way that is less likely to introduce side effects.