Touchscreen Display Test Area Validation
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Solution Overview
Problem
Existing touchscreen displays, particularly in safety-critical environments like avionics and process control, face challenges in confirming and validating touch inputs effectively, requiring additional safety measures beyond standard validation methods.
Innovation Solution
A touchscreen display system with a dedicated test area connected to both the touchscreen and auxiliary controllers, allowing for the simulation of touch events and sensitivity testing through test signals and response signal comparison, enabling remote validation and sensitivity assessment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard touch validation methods are used, then the touchscreen can operate, but safety-critical requirements cannot be sufficiently met
Solution Approach 1:
The touchscreen display is segmented into a user-input area and one or more separate test areas. The test areas are dedicated regions that can be independently activated for validation purposes without interfering with normal user input operations. This segmentation allows the system to meet safety-critical requirements by providing dedicated validation zones while maintaining the functionality of the user-input area.
Solution Approach 2:
An auxiliary controller is introduced as an intermediary component between the touchscreen controller and the validation system. The auxiliary controller receives test signals, activates test areas, and compares response signals with expected values. This intermediary layer simplifies the overall system architecture by centralizing the validation logic and providing a clear separation between user input handling and safety validation functions.
2Reliability
If test areas are separate from user-input area, then touch confirmation can be validated, but active area utilization is reduced
Solution Approach 1:
Different regions of the touchscreen are assigned different functions: the user-input area is optimized for normal operation while test areas are specifically designed for validation purposes. This local differentiation allows each region to perform its specialized function effectively. The test areas can be positioned in locations that minimize impact on the overall active area while still providing sufficient space for validation operations.
Solution Approach 2:
The validation functionality is added as a separate dimensional layer rather than competing for the same spatial resources. By using the auxiliary controller to manage test area activation and validation logic, the system adds validation capabilities in a functional dimension rather than requiring additional physical space, thereby minimizing the impact on active area utilization.
3Area of stationary object
If test areas are within user-input area, then active area is maximized, but user input may be affected
Solution Approach 1:
The test areas are dynamically activated and deactivated based on validation needs rather than being permanently active. The auxiliary controller can selectively enable test areas during validation sequences and disable them during normal user operation. This dynamic behavior ensures that test areas do not interfere with user input while still providing comprehensive validation coverage when needed.
Solution Approach 2:
Validation operations are performed periodically or on-demand rather than continuously. The auxiliary controller activates test areas in periodic validation sequences or in response to specific triggers, allowing normal user input operations to proceed uninterrupted between validation cycles. This periodic activation minimizes interference with user operations while maintaining validation effectiveness.
4Reliability
If multiple test areas are provided, then comprehensive testing is enabled, but device complexity increases
Solution Approach 1:
Multiple test areas are designed with universal characteristics, allowing the same validation logic and comparison procedures to be applied across all test areas. The auxiliary controller uses a unified approach to manage all test areas, activating them in sequences and applying consistent validation rules. This universal management approach reduces the complexity that would otherwise arise from having to manage each test area independently.
Data Source
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AI summary
A touchscreen display system is described that has a touchscreen display (10) comprising an active area (11) and an user-input area (1), a touchscreen controller (4) and an auxiliary controller (5) the active are (11) and the user-input area (1) being connected to the touchscreen controller (4) and to the auxiliary controller (5), wherein a part of the active area (11) comprises at least one test area (3) allocated for test operations. Instructions are provided to assert the test areas to states of validated touches, a response signal is provided relating to the coordinates corresponding to the validated touches, and the signal is compared with the initial instruction.