Research On The Image Source Drive Control Of The Holographic Waveguide Display

In recent years,Augmented Reality(AR)has set off a boom in the civilian consumer market.Holographic optical waveguide technology is a way to realize augmented reality.Based on the principle of Bragg diffraction and waveguide transmission,holographic optical waveguide technology has the advantages of thin volume,large exit pupil area,low cost of mass production,so it is a promising AR technology scheme.At present,the mainstream AR products in the market are head mounted display(HMD)devices,whose background is easy to change,so the display brightness of the micro-image source should be controlled in real time.Once the brightness changes,the Gamma characteristic also changes,which requires the device to achieve control of the Gamma characteristic quickly and accurately.The traditional Gamma correction method is complex and cannot meet the requirements of fast and accurate control of HMD devices.To solve this problem,a fast Gamma adaptive correction algorithm is proposed in this thesis.Subsequently,based on the principle of holographic waveguide display,a HMD device is designed,and the Gamma correction algorithm is successfully applied to the device.The specific work is as follows:(1)A fast adaptive Gamma correction algorithm based on Microcontroller Unit(MCU)is proposed.The algorithm has strong applicability.Firstly,the brightness of a set images with uniform gray value changes is measured,and then the relationship between brightness and data voltage is fitted by using analysis and processing software.Finally,the relational expression and the target Gamma curve are stored in MCU to complete the mapping.The standard Gamma correction with different γ values can be realized quickly by using this relational expression.At the same time,the multi-voltage curve fitting makes the algorithm have the function of brightness adaptive correction.(2)A split HMD device scheme based on holographic waveguide display is designed.The device is divided into a drive unit and a control unit,which need to be connected by cable.The drive unit is enclosed by a goggle,which can hold all the components of the holographic waveguide display structure.The control unit can be a portable computer,mobile phone and other mobile devices,or a night vision control box developed by cooperative unit,which can provide power signals,video signals and control signals for the drive unit.(3)A real-time online control method of image source based on USB(Universal Serial Bus)interrupt is implemented.USB interrupt control has the advantage of flexibility and precision,it works well in the control of brightness,Gamma,display mode,video flip and other related performance.Qt Creator software was used to implement the development of USB application on mobile device,which makes the performance control more simple.The results show that the Gamma correction algorithm proposed in this thesis is feasible and can be used to control the micro-image source of HMD device in real time.The main work of this thesis is based on OLED(Organic Light Emitting Diode),but the relevant methods,designs and conclusions have direct reference significance for other types of micro-image source device applications.