Digital Optic System provides a clear, highly magnified image of the LCD, which is viewable regardless of environmental conditions and may be seen clearly by the vast majority of people, regardless of vision.
 Optical Design
The extremely small physical size of the display characters is such that they cannot be viewed close to the eye without high magnification. To help determine the minimum acceptable magnification, the displayed characters in existing dive computers were used as a reference point. Through limited subject testing using primarily Navy personnel (30 test subjects) we established a comfortable viewing reference distance of 10 inches (254mm). Approximately 75% of subjects tested could comfortably read alpha-numeric text height of 0.25-in (6.35mm) at the reference distance. More than 90% of test subjects could comfortably read text height of 0.375-in (9.5mm) at the same distance. This included test subjects who normally used glasses for reading. An additional margin was added to the test data results, and a minimum optical magnification requirement for the IDDM was established as 0.50-in (12.7mm) primary character height at the reference viewing distance.
Initially, we tested a large number of commercially available lenses with widely varying performance. Our best results were realized using a 0.86-in (21mm) diameter x 10X magnification lens that met all our basic optical requirements for magnification, eye relief, and physical size with acceptable distortion.
To determine if the optical performance could be significantly improved, we retained a leading optical design firm to design a custom lens with improved characteristics over the commercially available lens. The custom solution surpassed our technical requirements in all areas - providing a 14X magnification (0.625-in [15.8mm] primary character height at 10-in [254mm] viewing distance). Additional analysis showed that this system would also provide sharper images with less distortion at the edges of the viewing area.
 Optical Alignment
The optical assembly components (lens, display, and backlight) must stay precisely aligned along a center-viewing axis relative to each other and with precise spacing between components. This center-viewing axis extending from the diver's eye is perpendicular to the lens surface. The diver views the magnified display by shifting the eye downward and slightly to the right. Two additional variables affect the diver's ability to view the display within the mask. The distance between the diver's eyes, or interpupillary distance (IPD), affects the alignment of the diver's eye to the lens. The diver's face shape also affects viewing alignment since it determines the way the mask fits on the diver's face. This required the design of a fixed alignment mount that could accommodate as many different divers as possible, despite varying IPDs and face shapes. Finding the optimum location and alignment angle for a fixed mount system was a considerable challenge, requiring extensive trial and error, and human factor subject testing.
After completing extensive testing using prototype masks with various alignment positions, the optimum alignment angle was achieved and incorporated into the digital 3D solid mask model.
Embedded Electronic Control
The IDDM embedded electronic system is a combination of electronics, sensors, electromechanical hardware, and controlling software. This distributed system processes the sensor data and presents it to the diver's display screen.
Through several iterations of integrating electromechanical and industrial design requirements, a well-balanced frame design with a natural distribution by function of the electronic, mechanical, and optical system components was developed.
The embedded electronic control system is located within this frame design and distributed in four subsystems: the controller, the display, the RF receiver, and the battery.
 Rapid Prototyping and Manufacturing
To produce interim and final prototype masks with such a complicated mechanical design it was essential to use state-of-the-art rapid prototyping techniques. Several interim prototype versions of the IDDM were produced using a process called stereolithography in order to test human factors, optical alignment, backlight intensity, and system integration. Stereolithography uses proprietary photo-reactive liquid polymer resins and ultraviolet laser light to produce functional prototypes from the digital 3D solid models.
Other Diving Applications
Military Special Operations:
The miniature display screen and control software can be customized for the specific diving apparatus and mission profile, with SOF combat swimmers able to monitor critical life support and mission data inside the dive mask - regardless of poor environmental conditions.
An IDDM system could also be modified for the US Navy MK-16 or similar UBA for use by EOD divers. Adapting the IDDM into a full facemask configuration is also possible. This future integrated full facemask system could potentially provide the EOD diver with depth, bottom time, cylinder pressure, oxygen level (PPO 2 ), and battery status without large wrist-mounted displays.
Recreational and Technical Divers:
An increasing number of civilian divers (deep, wreck, cave, photographers, and marine biologists) are using enriched air, other mixed-gasses, and commercially available rebreathers to extend dive time at depth, and reduce decompression obligations. A modified version of the IDDM could similarly provide enhanced safety and effectiveness for these applications.
Public Safety Divers:
These divers typically perform rescue and recovery operations in environmental conditions with little or no visibility. Police and other specialist divers may be required to operate special equipment (such as hand held sonars), or perform special missions, which make monitoring critical life support data very difficult. A custom IDDM could enhance safety and mission effectiveness here.
Handicapped or Physically Challenged Divers:
A growing number of handicapped, or physically challenged individuals are entering the realm of recreational diving. Organizations such as the Handicap Scuba Association International and the International Association of Handicapped Divers specialize in training handicapped individuals to scuba dive. One challenge for instructors is enabling the handicapped diver to monitor his or her depth, bottom time and cylinder pressure. This is difficult since many times the handicapped diver cannot manipulate limbs into a position to view gauges, dive computers, watches, or consoles. In these instances the handicapped diver must rely solely on his or her dive buddy to monitor life support data. An IDDM would allow the handicapped diver an added level of control, confidence, and peace of mind by allowing direct monitoring of dive data.
Above Articles: DataMask HUD(1)
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