RU2431802C2 - Portable navigation device - Google Patents

Abstract

FIELD: instrument making.

SUBSTANCE: colour pattern and screen content of a navigation device monitor are assessed and generated. At the same time it is defined at least for one specified condition of the surrounding lighting, monitoring and evaluation of a signal that specifies conditions of the surrounding lighting, whether display settings are used for current conditions of the surrounding lighting, and, if required, changes are made to display settings, so that they correspond to current conditions of the surrounding lighting.

EFFECT: expansion of functional capabilities.

34 cl, 9 dwg

Description

LINK TO RELATED APPLICATIONS

This application claims priority for patent applications in the United Kingdom of Great Britain and Northern Ireland with serial numbers 0604709.6, 0604708.8, 0604710.4, 0604704.7, and 0604706.2. The above patent applications are incorporated herein by reference.

BACKGROUND

1. FIELD OF THE INVENTION

The present invention relates to a portable navigation device, including functionality for automatically adjusting display settings to suit various ambient lighting conditions.

2. Description of the Related Art

Navigation devices based on the global navigation system (GPS, GPS) navigation and location are known and are widely used as in-car navigation devices. The link can be made to devices that integrate the GPS receiver into a computing device programmed with a cartographic database, and which can generate navigation commands on the display device, such as TomTom's TOMTOM GO device. These portable, integrated devices are often installed on or in the vehicle dashboard using a vacuum fastener or docking device.

Reference may also be made to the software of the Navigator series from the assignee of the present invention, TomTom International B.V. This software, when executed in a personal digital assistant (PDA) with a GPS receiver (such as COMPAQ IPAQ) or connected to an external GPS receiver, allows the user to enter the address of the departure and destination points in the PDA. The software then calculates the best route between the two destinations and displays instructions for navigating that route.

The term “navigation device” refers to a device that enables a user to navigate to a predetermined destination. The device may have an internal system for receiving location data, such as a GPS receiver, or it may simply be connected to a receiver that can receive location data. The device can calculate the route on its own, or interact with a remote server that calculates the route and supplies navigation information to the device, or be a hybrid device in which both the device and the remote server both participate in the route calculation process. GPS-based portable navigation devices are not permanently embedded in the vehicle, but instead are devices that can easily be inserted, or docked, or otherwise used inside the vehicle. Usually (but not necessarily), they are completely autonomous, that is, they include an internal GPS antenna, navigation software and map data, and therefore can draw and display a route to be considered.

By using positional information received from an internal or external GPS receiver, the software can determine the position of the navigation device or PDA (usually installed on the vehicle dashboard) at regular intervals and can display the current position of the vehicle on a map and display (and sound ) proper navigation commands (e.g. 'turn left after 100 m') on the screen.

A graphic depicting the actions to be performed (for example, a left arrow indicating a future left turn) can be displayed in the status bar, as well as overlaying on applicable intersections / turns of roads, etc. on the roads shown on the map itself. The display device of the navigation device may consist of a liquid crystal display (LCD) to show the user’s location on the map and any information related to the surroundings and the planned route. One example is the SAMSUNG LTE400WQ-E01 Active Matrix LCD module with integrated touch panel and backlight.

A set of colors for displaying a map or showing menu items on a screen of a navigation device may be predetermined, and various sets of colors may be stored as color schemes (color combinations). The user can also adjust the backlight level of the display device, which can vary from the level of full backlight to turn off the backlight completely.

One common approach is for the user to manually change the display brightness settings when changing external light, for example, increase the brightness when using a navigation device or PDA in direct sunlight or reduce the background illumination in dim lighting situations, such as at night or when driving in a tunnel. In these situations, the default brightness setting may not be appropriate, as the display may either be too dark or too bright for the given lighting conditions. Lower backlight levels may also be desirable for lower power consumption and longer battery life.

It is also possible to configure the navigation device or PDA to use predefined color schemes for menus, maps, and navigation screens. Some color schemes use high contrast colors that remain visible even in direct sunlight, other color schemes are suitable for people who do not distinguish between colors (with color blindness), and it is also known to use color schemes that are more suitable for the environment. low light environments or when using a navigation device or PDA at night.

However, it is not known to gradually change the brightness of the display device of the portable navigation device depending on the current ambient light conditions and user selectable options. It is also not possible to make automatic adjustments with respect to display brightness and / or color schemes without interacting with the user, where and when this is most desirable.

The present invention provides means for changing display settings to match current ambient light levels, and for providing user selectable preferences for automatically adjusting display settings when changing ambient light levels.

SUMMARY OF THE INVENTION

The invention is a navigation device comprising a processor configured to monitor signals indicative of ambient lighting conditions and select display settings assigned to current ambient lighting conditions. The invention is also a method for automatically adjusting display settings of a portable navigation device in accordance with current ambient lighting conditions.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be described with reference to the accompanying drawings, in which:

Figure 1 is a block diagram depicting the elements of a navigation device that implements the present invention;

Figure 2 is a snapshot of the screen of the navigation device; a snapshot of the screen shows a three-dimensional navigation view suitable for daytime use and a status bar running along the bottom of the display;

Figure 3 is a snapshot of the screen of the navigation device, the screen shot shows a three-dimensional navigation representation suitable for use at night, and a status bar running along the bottom of the display;

4 is a block diagram illustrating an implementation of the invention,

5 is a snapshot of the screen of a navigation device, a screenshot shows a preference screen with buttons for changing map colors and display brightness,

6 is a snapshot of a screen of a portable navigation device, a screenshot shows a screen of brightness preferences,

7 is a snapshot of the screen of a portable navigation device, a screenshot shows a preferences screen with a button for manually switching between day and night view,

FIG. 8 is a diagram for transitioning between a day and night view according to one embodiment of the invention, FIG.

9 is a diagram for transitioning between a day and night view according to another embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

1 is a block diagram showing various elements of a navigation device according to the invention. The main components of the navigation device are enclosed in a portable housing 1. The navigation device comprises a storage device 10, the type of which may be internal (such as a hard disk drive, flash memory, random access memory, read only memory or the like) or removable (such as a board memory, memory card, CD, digital versatile disk or the like). The navigation device may include both internal and removable storage devices at the same time.

The location of the navigation device is calculated using positional (eg, GPS) data 9, which is received from the GPS receiver 12. The GPS receiver 12 may be internal or external, connected to the navigation device via wires or wireless communications.

The navigation device comprises a processor 4 for performing tasks related to navigation in accordance with programmed commands and user interaction. The processor 4 exchanges information with various elements of the navigation device via the data bus 6. The map data 7, user data 8, GPS data 9 can be accessed by the processor 4 via the data bus either directly or through other elements that are outside the scope of the present inventions.

The navigation device comprises a display device 2 showing a map and navigation commands and providing the user with access to various functions of the navigation device using a graphical menu system. The colors and contents displayed on the screen are controlled by the processor 4 in accordance with the programmed functions, the planned route and the location of the navigation device. In other implementations, a separate image processor may be used for graphics tasks.

The display device 2 includes a light source 3 for backlighting. The light source 3 can provide various output levels, such as, for example, pulse-width modulated light emitting diodes. Backlight levels are controlled by processor 4 or a separate image processor.

Color schemes 11 are also stored in the storage device 10 or in other special areas of the navigation device. The color scheme can be stored as a plug-in file. A plug-in file is a special separate piece of software that interacts with the main application, in this case, the main software of the navigation device, to perform a specific task. A plug-in file can implement (for example, store, retrieve, manage) color correlation and color conversion.

A user of the navigation device can control the navigation device using various buttons (not shown) or a tactile user interface, such as a touch screen or touch keyboard, or through voice commands. In this example, the user can interact with the navigation device using the touch screen display device 2, which is also connected to the data bus 6.

The navigation device may comprise an on-board light sensor 5a or may have an interface with an external light sensor 5b. The light sensor is a specialized diode or transistor that provides an output signal in accordance with the current conditions of ambient lighting. The processor 4 receives a signal from sensors 5a or 5b indicating ambient light conditions. The signal from the sensor 5a or 5b is taken into account by the processor 4 to select and change the display settings of the navigation device. A signal indicating ambient light conditions may not be taken into account immediately in order to filter out sudden, temporary changes in ambient light conditions. A buffer of 10 seconds to 150 seconds can be used to prevent unwanted changes between display modes due to temporary changes in ambient light conditions.

Figure 2 shows a snapshot of the screen of a personal navigation device. The screenshot shows a typical three-dimensional navigation view 1 and status bar 2 along the bottom of the screen. Roads, building groups, parks and water areas are displayed using different colors. The overall appearance is therefore similar to a paper card. An arrow 3 indicating the current position of the device is shown in the center of the screen. If the user of the navigation device or vehicle on which the navigation device is installed moves along route 4, the navigation view 1 is regularly updated by scrolling the map and rotating so that the arrow 3 indicating the current position remains in the center of the screen, pointing up. The central area of the screen is located in the lower half of the screen; at an equal distance from the left and right edges of the visible (on the screen) area of the map. The user of the navigation device follows route 4 to reach the desired destination (not shown in the drawing).

Status line 2 provides area 7 with information regarding trip details. Icon 8 “next command” indicates what is the next maneuver to be performed by the user, and how far the current location is from the place of maneuver so that the user has enough time to prepare for the next maneuver. Icon 8 “next command” may be accompanied by respectively synchronized speech instructions played through the speaker of the navigation device, or using external audio playback devices such as headphones or a car audio system.

It should be noted that in line 2 of the state, character types with the appropriate size, color and placement are used on top of a contrasting color background to facilitate the ability to read content in high light conditions. This example uses sets of white fonts over a dark blue background. Alternatively, various color combinations may be used to provide the user of the navigation device with sufficient readability. This color combination includes yellow, white, green, or light gray text over a black, dark gray, brown, or dark blue background. Optionally, the text and background colors can be swapped or inverted.

Streets 5 and main roads 10 are drawn using light colors such as white and yellow, while the names of 6 streets are displayed in black to provide sufficient contrast. Additional color combinations may be possible as described above. “Next action” is also marked on the map with arrow 9. In this example, arrow 9 is drawn in green, which remains visible if superimposed over streets 5 and main roads 10. It is also possible to use any other color that differs from the colors below the arrow 9.

The set of colors to be used in the navigation view is called the color scheme. The color scheme contains information regarding the types of map elements and the colors associated with them. In addition to map elements, the color scheme may also contain information regarding the colors to be used in the status line 2 and the colors to be used for other elements shown in the navigation view 1, such as: zoom buttons 11 and 12; marker 3 of the current position; names of 5 streets; water 6, arrow 9 for the next step and any other elements on the screen, as well as those not shown in Figure 2, such as tunnels, bridges, highways, pedestrian streets, railways, private roads, utility roads, bypass routes, lanes for buses, etc.

It is also possible to enhance the backlight of the display device of the navigation device, especially when it is used in direct sunlight, and to reduce the backlight when used in dark environments to provide good readability in various lighting conditions in addition to using different sets of colors.

Figure 3 shows a snapshot of the screen of a navigation device. The screenshot shows the same three-dimensional navigation representation 1 and status bar 2 as in FIG. 2, but using a different color scheme that is suitable for a dark environment, where the sharp, contrasting colors of FIG. 2 can be annoying for the user of the navigation device . In this example, the brightest color is used to indicate planned route 4, while other elements are drawn using relatively dark colors. Some elements, such as the river 12 shown in FIG. 2, disappear almost completely in the background of the image, and the green of the park area 13 at the top edge of the screen is completely dark to represent an almost realistic night view of the environment surrounding the navigation device.

It is also possible to draw a schematic representation of the night sky in an area close to the top of the screen where the information of the corresponding map and routing is not displayed. This will compensate for the loss of detail compared to the representation of FIG. 2. Stars in the night sky can be reproduced using white, yellow or light gray color dots of 1 or 2 pixels in the upper third of the visible area to create a better sense of space even though fewer details are shown than in the view shown in Figure 2.

The color scheme used in Figure 3 helps the user of the navigation device to identify those elements that are more likely to be appropriate at night. In addition, in comparison with FIG. 2, fewer varieties of colors are used, therefore, the names of 6 streets, route 4 and information 9 regarding the next action are distinguished even against a color background consisting of other map elements. Such a color scheme will result in lower screen flicker and less distraction for the user of the navigation device at night, while it will still allow sufficient visibility as opposed to color schemes with lighter, more diverse and brighter colors. The same or similar color scheme may be useful when a device user enters a tunnel or other area with significantly worse lighting conditions than during normal daytime use.

4 is a block diagram illustrating the present invention. The navigation device stores in its storage device various data that is required to perform functions related to navigation. The data may include map data, satellite data, user data, audio and text files, software for navigation and related operations, as well as configuration files, preferred settings files and operating system files. The storage device may be one of: random access memory, a hard disk drive, flash memory, a removable storage device board, and any suitable volatile or non-volatile storage medium. The processor of the navigation device is connected to the storage device and performs various operations, if and when they are required, based on programmed commands and / or user interaction. The processor may perform read and write operations. The processor is able to delete, move and modify data in any way necessary for the operation of the navigation device.

In the first step of FIG. 4, the processor of the navigation device monitors a signal indicating ambient lighting conditions. In this embodiment, a signal is received from a light sensor mounted on a printed circuit of a navigation device.

The light sensor is a photosensitive diode or transistor that generates an output signal that depends on the amount of light incident on the surface of the diode. If the relationship between the amount of light on the diode and the corresponding output signal is known, it is possible to reliably distinguish between different lighting conditions, such as daylight and night, or, optionally, use a finer degree of detail to further distinguish between an arbitrary number of transient lighting conditions between daylight and night. Light sensor manufacturers publish corresponding diode performance, such as the TOSHIBA TPS851 model, that can be used in this implementation of the invention. In other implementations, it is also possible that the light sensor is connected externally to the navigation device, and it is also possible that the sensor is able to distinguish only two conditions and provide an output signal indicating one of these two conditions. Other sensors may be used to indicate current lighting conditions, such as a headlamp level indicator, to give a good assessment that ambient light levels have decreased if the headlights of a vehicle are turned on.

At the first stage, the processor of the navigation device monitors a signal indicating the current lighting conditions. In the next step, the processor evaluates the signal and then proceeds to select the appropriate display setting that has been assigned to the current lighting condition. The processor proceeds to change the current display settings to the selected display setting after it is determined that the current display setting is different from the setting assigned to the current lighting condition.

The designated display setting may contain one of the color schemes described above, and may also contain predefined backlight levels and optionally show or hide details on the screen.

A display setting suitable for daylight conditions may include a backlight level set to the maximum value, and a color scheme using realistic, similar to daylight colors and displaying map information in the same way as on cards on paper.

Another display setting for night use may include a lower backlight level that may be in the lower half of the backlight range, for example, set to 15 percent, in combination with the same color scheme as above, or with a different color scheme using colors that are similar to representing the area surrounding the user at night. It is also possible that the color scheme for night use applies the inverted colors of the color scheme intended for daytime use.

It is also possible that the night view indicates objects that are not visible during the day, such as stars, a street lamp, and it is also possible to configure the night view with the ability to disable some objects or functions that are more likely to be relevant during the day, and allow functions that may be suitable for the user of the navigation device at night or in the dark. Thus, in addition to using a predetermined set of colors to display the contents of the screen, the day or night view may show various pieces of information, which may include at least one of: a star map, points of interest, information regarding map elements or planned route and menu items. Day or night view can also enable or disable some functions of the navigation device, which can be at least one of: warning about speed limits, warning about interruptions of traffic and updating information about traffic or weather. Therefore, when switching to day or night view, the navigation device will retrieve information regarding road conditions, such as congestion or traffic jams (road temperature) and the like.

In the following, attention is shifted to FIGS. 4, 5, and 6, which describe various configuration options for a user of a navigation device.

Figure 5 shows a snapshot of the preferences menu of the navigation device. The menu is based on different icons and text labels, each of the icons represents a different configuration option. On some navigation devices, configuration options may be available through a text-only menu.

The icon 51 in the lower left corner is labeled “Change map colors”, and by selecting it, the user of the navigation device can select map colors that are most suitable for the current work environment or other parameters, similar to the user's personal preference. Some color schemes were designed to create a more realistic representation of the actual landscape, while others were adopted for color blind people, while others were designed around various themes, such as the official colors of the country's national football team. Some color schemes correspond to regional differences in the color coding of paper maps and road infrastructure.

In the color schemes of the present invention, it is common that any objects that can be displayed on the screen have a relationship with color. The color relationships in the color scheme may be predetermined and fixed, or it may be possible for the user of the navigation device to select colors for individual map objects and elements displayed on the screen.

According to this embodiment, some card colors are more suitable for daytime use, while others are more suitable for nighttime use. The user can manually associate one color scheme using at daytime and associate another color scheme using at night, or the corresponding day and night color schemes can be stored as a factory setting in a storage device as part of the navigation device. The icon 52 in the central lower area of the preferences menu opens the brightness preference screen, which will be described in more detail in Fig.6.

6 is a screen shot of a brightness preference menu of a navigation device according to the invention. The screenshot indicates the first slider 61 to select the backlight level to be used during the day and the slider 62 to select another backlight level to be used during the night. Backlight levels can be selected independently of each other or as a ratio to each other. In the example shown in FIG. 6, the daylight backlight level is 90 percent of the available range and the nighttime backlight level is 15 percent of the range. Alternatively, the user can specify the desired ratio, for example, daylight brightness of 90 percent of the available range and night brightness of 15 percent of the selected daylight brightness. It is also possible that the user of the navigation device wishes to use a higher level of backlight at night than during the day. This is possible by installing sliders 61 and 62, respectively.

At the bottom of FIG. 6, check boxes 63 and 64 were indicated. The check box 63 is marked if the user wishes to rely on the navigation device to adjust the display backlight between two levels, as can be selected using the sliders 61 and 62. If the checkbox 63 has the unchecked box; the user will be able to manually set the backlight levels. The check box 64 is checked if the user of the navigation device wishes to rely on the navigation device to switch between day and night color schemes in accordance with the mechanism illustrated in Figs. 8 and 9. If the user unchecks the check box 64, the navigation device supports the use of the current color scheme regardless of lighting conditions.

Figure 7 illustrates the configuration menu of the navigation device, and the user can manually switch between day and night colors using the button 71. If you select the night time display setting by pressing this button, then the check buttons 63 and 64 (Fig.6) will not be taken into account by the navigation device.

8 is a transition diagram illustrating various display settings of a navigation device in response to various lighting conditions. The horizontal axis 1 represents the level of the input signal received from the light sensor. When the input signal indicates low ambient light conditions, that is, the input signal is below threshold 2, the navigation device uses the night color scheme and display setting for night time. When the input from the light sensor indicates daylight conditions, that is, the signal level is above threshold 2, the navigation device uses the day color scheme and display setting for daytime. The threshold value 2 has been set to a value corresponding to the level of ambient light, below which the average user will use the night color scheme. The threshold value 2 may be a factory setting or it may be set by users of the navigation device in accordance with their personal preferences.

The vertical axis 4 represents the brightness of the screen in the range from 0 to 100 percent. In this example, the daylight brightness 5 is set to 100 percent, and the night brightness 6 is set to approximately 25 percent. Night brightness 6 is used while the light sensor input is below threshold 2, and daylight 5 is used if the light sensor input is above threshold 3.

In another embodiment, the threshold value 2 and the threshold value 3 are identical, that is, they are located at the same point on the horizontal axis 1. In this case, when the signal indicating the ambient light conditions increases above the combined threshold value 2 and 3, the display settings instantly change from night brightness to daylight brightness. Similarly, if a signal indicating ambient light conditions falls below a combined threshold of 2 and 3, the display settings instantly change from daylight to night brightness.

On Fig shows a smooth transition along line 7 between the levels of night brightness 6 and day brightness 5, while the input of the light sensor is between threshold value 2 and threshold value 3, which are set to different values on the horizontal axis 1. In this case, additional display settings to different parts of the transition line 7. Additional display settings can be created using day color schemes and gradually changing backlight levels or night color schemes and gradually changing backlight levels.

In a preferred embodiment, between the levels of night brightness 6 and day brightness 5 are assigned at equal intervals 5 different levels of backlight without changing the color scheme. This arrangement provides for the gradual dimming of the backlight of the display device in response to lower ambient light levels. In this example, four points 2A, 2B, 2C and 2D are shown on the horizontal axis 1 between the threshold value 2 and the threshold value 3. The number of points can be different, points can be placed arbitrarily between threshold values 2 and 3, or they can be distributed at equal intervals.

If the signal indicating the ambient light conditions falls to threshold value 3 on the horizontal axis 1, the screen brightness decreases to the value associated with threshold 2D, which is proportional to the value of daylight brightness 5 and night brightness 6 (in this example, 100 and 25 percent respectively). The brightness of the screen remains at the value associated with the 2D threshold, until the decreasing signal actually reaches the 2D threshold. At threshold 2D, the screen brightness changes to a value associated with threshold 2C; and the brightness of the screen remains unchanged until the decreasing signal actually reaches a threshold value of 2C. Similarly, at the threshold value 2C, the brightness of the screen changes to a value associated with the threshold value 2B; and at the threshold value 2B, the screen brightness changes to a value associated with the threshold value 2A. Finally, at the threshold value 2A, the screen brightness changes to a value associated with the threshold value 2, which is the night brightness value 6; and the brightness of the screen remains unchanged until the signal falls below threshold 2. The change from day colors to night colors can occur at one of threshold values 2, 2A, 2B, 2C, 2D and 3, depending on the factory or user configuration.

Similarly, when increasing the signal level relative to the horizontal axis 1 in response to increasing levels of ambient light, the navigation device is configured to change from night color schemes to day color schemes at threshold 2 and to gradually increase the backlight of the display from night brightness to day brightness along line 7 until the light sensor input indicating the ambient light conditions reaches threshold value 3. A detailed procedure is as follows.

The screen brightness remains at night brightness level 6 until the signal indicating the ambient light conditions is below point 2A, or alternatively below threshold 2. If the rising signal reaches threshold 2A, the screen brightness changes to the level assigned to this given point , which is a proportional value, and can be read along the vertical axis 2, somewhere between night brightness 6 and day brightness 5 (in this example, 25 and 100 percent, respectively). At threshold value 2B, the screen brightness increases to the level assigned to this given point, and after that remains unchanged until the signal reaches threshold value 2C. The screen brightness continues to change in a similar way to the threshold values of 2C and 2D. Finally, at a threshold value of 3 or higher, a daily brightness of 5 is used, which in this example is 100 percent.

In the above examples, there are four transition points between night brightness 6 and day brightness 5, providing a good degree of detail without having to store a large number of settings. In other implementations, any larger or smaller number of transition stages may be used, or there may also be a stepless, continuous transition.

Above threshold 3, daily display settings are used unless the user of the navigation device manually selects a different display setting, for example, by pressing the button 1 in Fig. 7 to use night colors, or by disabling the check buttons 3 and 4 in Fig. 6. In other implementations, other configuration options may be available to manually prohibit switching between day and night color schemes. The user can simply select the same color scheme and the same level of backlight for day and night use in order to prohibit any automatic change.

Figure 9 shows a modified transition scheme compared to Figure 8. In Fig. 9, the daily brightness level 5 has been reduced to a new daily brightness 5 ', the difference is indicated by arrow 9. The night brightness 6 has been changed to a new night brightness 6', the difference is indicated by arrow 10. The new configuration can be compared with the previously described transition line 7, as seen on the new transition line 7 '. Using the new transition line 7 ', the steps between the new night brightness 6' and the new daytime brightness 5 'are smaller, but the transition is still smooth, gradual until threshold values 2 and 3 become the same.

In the above examples, ambient light conditions are measured using a light sensor coupled to the processor of the navigation device. The light sensor may be an integral part of the navigation device, or it may be an external sensor connected to a suitable connector of the navigation device or its docking device.

In other schemes, an external sensor may transmit radio signals, such as Bluetooth or infrared signals indicating ambient lighting conditions. For example, a radio signal transmitter may be directly or indirectly connected to an in-vehicle light sensor or a headlamp light sensor and configured to transmit radio signals to a navigation device, the signals indicating ambient lighting conditions. The proper installation of a Bluetooth or infrared transmitter device is well known to those skilled in the art and is outside the scope of the invention. A navigation device capable of Bluetooth or infrared communication can monitor radio signals indicating ambient lighting conditions and implement the invention in accordance with the appended claims.

In the absence of a signal from a light sensor or similar hardware component, or in addition to them, the software in the navigation device can also monitor the current position of the navigation device and compare it with the map data for the purposes described above. By comparing the map data with the current position, the software of the navigation device may indicate that the current position is in a tunnel or in an underground car park, which is interpreted as a signal indicating low ambient light conditions. Lack of positional data (i.e. loss of GPS signal) may also indicate that the current location is a tunnel or underground car park.

In this case, an indication of the ambient lighting conditions does not require a hardware component implemented in or connected to the navigation device. A signal indicating lighting conditions may be generated using software such as at least one of map data, user data, time data, and configuration data.

In a further embodiment, the navigation device may request confirmation from the user before or after a change between the day and night color schemes after determining that the current display setting is not a display setting assigned to the current ambient lighting conditions. To change the display settings, a selection screen or confirmation dialog may be presented to the user of the navigation device.

If the navigation device is removed from the vehicle, that is, if it is revealed that the device has been undocked, the user can select additional possible options that contain at least one of: confirm undocking, choose whether or not to monitor a signal indicating the lighting conditions , selecting the color scheme to be used, and selecting the backlight level to be used. A similar choice is possible when docking a navigation device in a vehicle.

The invention has been described with reference to some preferred embodiments. However, it will be understood that modifications and changes are possible within the scope of the attached claims.

Claims (34)

1. A portable navigation device comprising
a processor and a storage device configured to assign and store at least brightness settings and display settings for relatively light and dark ambient lighting conditions,
an ambient light sensor, configured to provide a signal indicating a current ambient lighting condition that the processor may evaluate,
means for setting said brightness settings and changing display settings,
wherein said processor evaluates whether the ambient light conditions are light or dark, and determines:
(a) whether the first option is set to allow the automatic change of the current display setting;
(b) whether the second option is enabled to automatically change the current brightness setting;
(c) whether the current display settings and / or the current brightness settings of the device are in conflict with those that have been assigned and stored for the estimated current ambient light condition,
and if definition (c) and at least one of definitions (a) and (b) are positive,
the processor automatically changes at least one current brightness setting and the current display setting to the appropriate assigned or stored setting. 2. The portable navigation device according to claim 1, wherein the brightness settings are obtained by backlighting illuminating to a custom predetermined level. 3. The portable navigation device according to claim 1, wherein the display settings for at least one ambient lighting condition comprise at least one of a proper presentation and color scheme. 4. The portable navigation device according to claim 3, wherein the color scheme includes a schematic representation of the sky in the daytime or night view, depending on whether the current ambient light condition is light or dark. 5. The portable navigation device of claim 1, wherein the display settings comprise a color scheme using brighter colors and the brightness level is relatively high when the current ambient light conditions are bright. 6. The portable navigation device of claim 1, wherein the display settings include a color scheme using darker colors and the brightness level is relatively low when the current ambient light conditions are dark. 7. The portable navigation device according to claim 3, wherein said color scheme is stored as a plug-in module. 8. The portable navigation device according to claim 2, further configured to change said current brightness setting by gradually changing the backlight levels from the current backlight level to the assigned and stored backlight level. 9. The portable navigation device of claim 8, wherein the gradual change in backlight levels comprises a predetermined number of incremental transitions ranging from the level of the current backlight for the current display setting to the stored backlight level. 10. The portable navigation device according to claim 9, in which a certain number of transitions is equal to five. 11. The portable navigation device of claim 1, wherein the signal indicating the condition of the ambient lighting is a signal from a light sensor. 12. The portable navigation device of claim 11, further configured to buffer said signal from a light sensor. 13. The portable navigation device of claim 12, wherein the light sensor is located on a printed circuit board of the navigation device. 14. The portable navigation device according to claim 1, wherein said signal indicating ambient lighting conditions comprises a signal from a headlamp light sensor. 15. The portable navigation device of claim 14, wherein said headlight sensor is connected by wire communication to said navigation device directly or via its docking device. 16. The portable navigation device of claim 15, further configured to request confirmation from the user when docking / undocking said navigation device. 17. The portable navigation device of claim 14, wherein said headlight sensor is connected wirelessly to said navigation device. 18. The portable navigation device according to claim 2, comprising a display device with a touch screen and backlighting a light emitting diode. 19. The portable navigation device according to claim 1, further configured to enable or disable at least one function of said navigation device when changing a display setting. 20. The portable navigation device according to claim 19, wherein said at least one function comprises one of: a star map, points of interest, information related to map elements or a planned route, speed limit warnings, motion interruption warnings , traffic information, weather information, menu items and menu color schemes. 21. A method for automatically adjusting the visibility of a display device of a portable navigation device, the method comprises the steps of:
assign and store at least brightness settings and display settings for relatively light and dark ambient lighting conditions;
assessing whether the signal representing the current ambient lighting condition is relatively light or dark,
determine
(a) whether the first option is set to allow automatic change of the current display setting,
(b) whether the second option is enabled to automatically change the current brightness setting,
(c) whether the current display settings and / or the current brightness settings of the device are in conflict with those that have been assigned and stored for the estimated current ambient light condition,
and if definition (c) and at least one of definitions (a) and (b) are positive,
the processor automatically changes at least one current brightness setting and the current display setting to the appropriate assigned or stored setting. 22. The method according to item 21, in which the brightness settings are obtained by means of a backlight illuminating to a custom predetermined level. 23. The method of claim 21, wherein the display settings for the at least one ambient lighting condition comprise at least one of a proper presentation and color scheme. 24. The method according to item 23, in which the color scheme includes a schematic representation of the sky in the daytime or night view, depending on whether the current condition of the ambient lighting is light or dark. 25. The method according to item 21, in which the display settings contain a color scheme that uses brighter colors, and the brightness level is relatively high when the current ambient lighting conditions are bright. 26. The method according to item 21, in which the display settings contain a color scheme that uses darker colors, and the brightness level is relatively low when the current ambient lighting conditions are dark. 27. The method of claim 23, wherein said color scheme is stored as a plug-in. 28. The method according to item 22, in which the current brightness settings are additionally changed by gradually changing the backlight levels from the current backlight level to the assigned and saved backlight level. 29. The method of claim 28, wherein the gradually changing backlight levels comprises a predetermined number of incremental transitions ranging from the level of the current backlight for the current display setting to the stored backlight level. 30. The method according to clause 29, in which a certain number of transitions is equal to five. 31. The method according to item 21, in which the signal indicating the condition of the ambient lighting is a signal from a light sensor. 32. The method of claim 31, further comprising buffering said signal from the light sensor. 33. The method according to item 21, in which additionally provide the ability to enable or disable at least one function of the aforementioned navigation device when changing the display settings. 34. The method according to claim 33, wherein said at least one function comprises one of: a star map, points of interest, information related to map elements or a planned route, speed limit warnings, traffic interruption warnings, information about traffic, weather information, menu items and color schemes of the menu.

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