Patent Grant
8487786
The present disclosure relates generally to the field of display systems. More particularly, the disclosure relates to the automatic brightness control of electronic display systems for use in aircraft and that may be used in low ambient light conditions.
Aircraft pilots and crew conventionally have difficulty viewing electronic displays in low ambient conditions. Auto brightness systems may not always respond appropriately to a change to low ambient light. When the display brightness is placed into automatic brightness mode, the display graphics and/or text may not be as visible in low ambient light conditions as compared to higher ambient light conditions with the same contrast ratio. This is because the human eye loses effectiveness in low ambient light conditions.
There is a need for an improved display system and method that can compensate for the effectiveness of the human eye in low ambient light conditions. There is also a need for a display system and method configured to adjust the contrast ratio or brightness of the display in low ambient light conditions and in normal ambient light conditions. There is further a need for a display system and method that provides increased readability in low ambient light conditions.
According to one exemplary embodiment, an aircraft display system includes an electronic display configured to provide at least one of graphical and textual elements and electronics configured to receive a signal indicating an ambient light level. The electronics set a brightness of the display using a first calculation in response to the desired contrast ratio and the ambient light level and using a second calculation in response to the desired contrast ratio and the ambient light level.
According to another exemplary embodiment, a method for setting a brightness of an aircraft display includes receiving a signal indicating an ambient light level at electronics, receiving a signal indicating a desired contrast ratio against ambient light level for the display at the electronics, and setting a brightness of the display using the electronics. The electronics uses a first calculation in response to the desired contrast ratio and the ambient light level and uses a second calculation in response to the desired contrast ratio and the ambient light level.
According to another exemplary embodiment, an aircraft display system includes means for receiving a signal indicating an ambient light level, means for receiving a signal indicating a desired contrast ratio against ambient light level for the display, and means for setting a brightness of the display using a first calculation in response to the desired contrast ratio and the ambient light level and using a second calculation in response to the desired contrast ratio and the ambient light level.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed.
These and other features, aspects, and advantages of the present disclosure will become apparent from the following description, appended claims, and the accompanying exemplary embodiments shown in the drawings, which are briefly described below.
Before describing in detail the particular improved system and method, it should be observed that the invention includes, but is not limited to, a novel structural combination of conventional data/signal processing components and display components, and not in the particular detailed configurations thereof. Accordingly, the structure, methods, functions, control and arrangement of conventional components software, and circuits have, for the most part, been illustrated in the drawings by readily understandable block representations and schematic diagrams, in order not to obscure the disclosure with structural details which will be readily apparent to those skilled in the art, having the benefit of the description herein. Further, the invention is not limited to the particular embodiments depicted in the exemplary diagrams, but should be construed in accordance with the language in the claims.
Referring generally to the figures, a system and method for adjusting a display brightness of an aircraft display is shown. The system can include an electronic display, user interface elements, an ambient light sensor, and electronics. The electronic display can be any type of display, including but not limited to primary displays, head down displays (HDDs), head up display (HUDs), secondary displays, head worn displays, etc. The system may operate in a manual brightness control mode or an automatic brightness control mode. In the manual mode, the user interface elements may be used to directly control the display brightness level. In the automatic mode, the electronics may use a sensed ambient light level from the sensor to adjust the display brightness for a desired contrast ratio set using the user interface elements. The electronics may make one calculation for low ambient light level conditions and another calculation for normal or high ambient light level conditions. The electronics may perform both calculations and select the higher calculated display brightness for use in adjusting the brightness of the electronic display.
Referring to
In some exemplary embodiments, flight displays 20 can provide an output from other systems of the aircraft. Displays 20 can include a weather display, a joint display, a weather radar map, a terrain display, and a head up display. Further, displays 20 may include an electronic display. For example, flight displays 20 can include a display configured to display a three dimensional or two dimensional perspective image of terrain, weather, navigation, or guidance information. Other views of terrain, weather, guidance, and navigation information may also be provided (e.g. plan view, horizontal view, vertical view, etc.). Additionally, flight displays 20 can be implemented using any of a variety of display technologies, including CRT, LCD, organic LED, dot matrix display, TFT, and others.
In various exemplary embodiments, flight displays 20 can also include head up displays (HUD) with or without a projector. The HUD is generally configured to display at least one of graphical and textual images or indicia. The images or indicia are displayed onto an otherwise generally transparent medium or combiner that the flight crew can see through. For example, the HUD may display navigational or guidance data overlayed onto a runway that the flight crew is viewing. The images may also be overlayed onto a view of terrain, other aircraft, cloud cover, low visibility conditions, other hazards, etc. In other exemplary embodiments, the medium on which the images are displayed may provide a synthetic view of various objects. For example, the medium may display an image of a runway, terrain, an obstacle, other aircraft, etc. that may or may not be otherwise viewable by the flight crew.
Aircraft control center 15 additionally includes one or more user interface (UI) elements 22. UI elements 22 can include dials, switches, buttons, touch screens, mous devices, trackballs, joysticks, or any other user input device. UI elements 22 can be used to adjust features of flight displays 20, such as contrast, brightness, width, and length. UI elements 22 can also (or alternatively) be used by an occupant to interface with or change the displays of flight displays 20. UI elements 22 can additionally be used to acknowledge or dismiss an indicator provided by flight displays 20. Further, UI elements 22 can be used to correct errors on the electronic display.
One specific UI element 22 may be used to set a manual or automatic mode for brightness and contrast adjustments of display 20 (e.g., an HUD or other display). Another specific UI element or knob may be used to adjust the brightness or contrast of display 20 based on the manual or automatic mode. If the manual mode is set, the knob may be used to directly adjust a fixed brightness of display 20. If the automatic mode is set, the knob may be used to set a desired contrast ratio that automatically adjusts the display brightness based on the ambient light level around the display, as is discussed in greater detail below.
Referring to
According to various exemplary embodiments, aircraft systems 50 may include at least one of a radar system, a communications system, a terrain awareness system, a navigation system, and any other aircraft system that generates data that may be useful to the flight crew. In an exemplary embodiment using a radar system, weather data, terrain data, and/or aircraft data may be provided for display on electronic display 70. In an exemplary embodiment using a communication system, communication data from a ground station or other aircraft (e.g., navigational data, weather data, communication messages, etc.) may be provided for display on electronic display 70. In an exemplary embodiment using a terrain awareness system, terrain data and/or obstacle data may be provided for display on electronic display 70. In an exemplary embodiment using a navigation system, navigational data (e.g., location, elevation, heading, bearing, drift, flight path, etc.) may be provided for display on electronic display 70.
Each aircraft system may generally include a transceiver 52 configured to send and receive data (e.g., radar data, terrain data, communication data, etc.) or to communicate with processing electronics 60 and display 70. Each aircraft system may also include processing electronics 54 configured to perform operations on received data or to format data for sending to processing electronics 60 or display 70.
Electronic display system 70 can be used to display information from aircraft systems 50 or other electronic equipment. Electronic display system 70 may include user interface (UI) elements 72, display 20, and a display driver 74. Display driver 74 can be any computer hardware and/or software that enables electronic display system 70 to communicate with and receive data from various other components. As described above, display 20 may be a head up display, a TFT display, an LCD display, or any other display suitable for use in an aircraft. UI elements 72 (e.g., knob, dial, button, touch screen, etc.) can be used for adjustment of display properties such as contrast, brightness level, dimensions, etc. As described above, UI elements 72 may include an element for setting a manual or automatic brightness control mode and an element (e.g., a knob or other element) for adjusting the brightness or contrast ratio based on the mode. UI elements 72 can also be used for selection of data shown on display 20 or to apply corrections to data shown on display 20. Input received from UI elements 72 may be provided directly to processing electronics 60 for further processing. Alternatively, input received from UI elements 72 may be processed by display driver 74. Display driver 74 may then communicate the received input to processing electronics 60 or various other components.
Processing electronics 60 may be configured to perform operations on data received from aircraft systems 50 or from UI elements 72. Processing electronics 60 may be configured to verify data received from aircraft systems 50 or to facilitate transmission of data to display 70 or to a ground station or another aircraft. Processing electronics 60 includes a processor 62 and a memory 64. Processor 62 may be any hardware and/or software processor or processing architecture capable of executing instructions (e.g., computer code stored in memory 64) and operating on various data types. Memory 64 may be any volatile or non volatile memory configured to store instructions or operations for execution by processor 62. Alternatively, memory 64 may be configured to store radar data received from aircraft systems 50, a ground station, or from another aircraft.
In addition to providing data to display 70 for display, processing electronics 60 may be able to adjust properties of display 70. For example, processing electronics 60 may adjust the contrast ratio, brightness, resolution, or other properties of display 70. Processing electronics may communicate with an ambient light sensor (ALS) 66 to receive data related to an ambient light level in the aircraft, for example in the cockpit or near the display. For purposes of this disclosure an area near the display may be a distance within ten feet of the display, within five feet of the display, within three feet of the display, within one foot of the display, etc. ALS 66 may be any ALS sensor capable of measuring ambient light in an aircraft cockpit. ALS 66 may be located in a combiner of display 70 (e.g., for a HUD) or in any other location of display system 30. ALS 66 may have the same field of view as the combiner field of view. ALS 66 then feeds a DC voltage back to the processing electronics 60 (e.g., in a range between about 0 to 5 volts). Processing electronics 60 then scales the DC voltage into foot lamberts using the following equation:
Ambient Light(fL)=K1×10(K2×Ambient Light VDC−1) (1)
Where K1 and K2 are calibration parameters. In one exemplary embodiments, equation (1) may be used for an ALS 66 using a voltage range of about 0 to 5V. In other exemplary embodiments, ALS 66 may have a different operating voltage range. In various exemplary embodiments, the calibration parameters or coefficients K1 and K2 allow equation (1) to be calibrated or tuned for various types of ALS 66.
Based on the ambient light level, processing electronics 60 may adjust the contrast ratio or display brightness of display 70. Adjustments of the contrast ratio or display brightness of display 70 may be calculated based on inputs received at UI elements 72. If the display system is set to an automatic brightness control mode, in typical or normal ambient light conditions processing electronics 60 may adjust the contrast ratio or brightness based on one calculation and adjust the contrast ratio or brightness in low ambient light conditions based on another calculation, as described in greater detail below.
Referring also to
When the brightness of display 70 is set to automatic mode, the desired display brightness is calculated based on a desired contrast ratio set by the pilot or flight crew via a display brightness knob (e.g., a UI element 22 or 72). The desired display brightness can vary with the sensed ambient light level to maintain the desired contrast ratio:
Desired Contrast Ratio=1+(Desired Display Brightness/Ambient Light) (2)
Processing electronics 60 calculates the desired display brightness based on the desired contrast ratio using the following general equation:
Desired Display Brightness=(Desired Contrast Ratio−1)×Ambient Light (3)
The ambient light is measured by ALS 66 as described above. ALS 66 generally has the same field of view (in size and shape) as display 70 (e.g., a combiner for a HUD).
Referring specifically to
Referring to
Ka is the brightness intercept point for the desired contrast ratio for a low ambient light level or is the minimum brightness level for a low ambient light level. Kb defines the slope that the display brightness changes for the contrast ratio based on the ambient light level. In one exemplary embodiment where display 70 includes an LCOS based image source, Ka may be less than about 0.1 and Kb may be less than about 1.0. In another exemplary embodiment using an LCOS based image source, Ka may be about 0.055 and Kb may be about 0.75. In other exemplary embodiments, display 70 may include other image sources and thus other Ka and Kb may have other values for optimizing the effectiveness of display 70 in low light conditions.
Referring to
According to various exemplary embodiments, equation (1) above may be used to define the Ambient Light quantity used in each of equations (2)-(4). Such a definition of ambient light leads to the following equations:
Contrast Ratio=1+(Display Brightness/10(Filtered Ambient Light Level−1)) (5)
Display Brightness=(Contrast Ratio−1)×10(Filtered Ambient Light Level−1) (6)
Referring to
Referring to
Exemplary embodiments may include program products comprising computer or machine-readable media for carrying or having machine-executable instructions or data structures stored thereon. For example, aircraft display system 30 may be computer driven. Exemplary embodiments illustrated in the methods of
It is also important to note that the construction and arrangement of the components as shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in dimensions, structures, shapes and proportions of the various elements, mounting arrangements, use of materials, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited in the claims. For example, elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. The order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments. Other substitutions, modifications, changes and omissions may be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present inventions as expressed in the appended claims.
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