Projection Display Apparatus Noise Reduction for Gesture Detection
Solution Overview
Problem
Existing projection display apparatuses face challenges in accurately detecting objects on a projection surface due to noise components within the illuminating unit, which affect detection accuracy and are not suitable for small-sized, stylish designs, especially under dark environments.
Innovation Solution
Incorporating optical members such as dichroic prisms and polarizing elements within the illuminating unit to reduce noise components, allowing for improved object detection accuracy while maintaining a compact and stylish design, and enabling operation under various lighting conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a projector unit and a detector unit are separately configured as independent units, then the pointing operation function is achieved, but the size of the whole system increases
Solution Approach 1:
The patent combines the projector unit and detector unit into a single integrated device. The projector projects images while the detector detects manual operations (gestures) within the projection area, merging two previously separate functions into one compact unit, thereby reducing overall system size while maintaining both projection and gesture detection capabilities
Solution Approach 2:
The integrated projector-detector device performs multiple functions simultaneously: it projects images like a traditional projector while also detecting manual operations and gestures within the projection area. This multi-functional design eliminates the need for separate detector units, achieving both projection and interaction capabilities in one device
2Measurement precision
If calibration operation is performed to ensure accuracy of relative positional coordinates, then pointing operation accuracy is improved, but the operation becomes cumbersome
Solution Approach 1:
The system performs automatic calibration without requiring manual intervention. The detector automatically detects manual operations within the projection area and establishes coordinate correspondence between the projection area and detection area, eliminating the need for users to manually calibrate every corner of the screen and significantly reducing operational complexity
3Measurement precision
If illuminating light is turned off during imaging, then imaging is not affected by illuminating light, but sufficient brightness cannot be assured under dark external environment
Solution Approach 1:
The patent separates the illuminating light and detection light into different wavelength bands. The illuminating unit uses visible light for projection while the detector uses infrared light for detection. This segmentation allows both functions to operate simultaneously without interference, maintaining brightness for projection while ensuring accurate detection in dark environments
Solution Approach 2:
Different parts of the optical system have different optical properties tailored to their specific functions. The illuminating unit is optimized for visible light projection while the detection unit is optimized for infrared detection. This local optimization allows each component to perform its function effectively without compromising the other, enabling simultaneous operation in dark environments
4Measurement precision
If a dedicated polarization converter element for imaging use is added, then imaging is not affected by illuminating light, but the projection lens becomes larger in size
Solution Approach 1:
The patent divides the optical system into separate illuminating and detection paths with different wavelength bands. The illuminating unit projects visible light while the detector captures infrared light. This segmentation eliminates the need for dedicated polarization converter elements, keeping the projection lens compact while ensuring imaging accuracy through wavelength-based separation
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enhances object detection accuracy by reducing noise components, allowing for a small-sized, high-definition, and interactive laser projector that can function effectively in both bright and dark environments.
Implementation Method 1
a second dichroic prism 132 that transmits blue light LB and the green light LG, and reflects red light LR
Implementation Method 2
a first dichroic prism 131 that transmits the blue light LB, reflects the green light LG, and transmits infrared light LIR
Implementation Method 3
a wire grid 27 that reflects a P-polarization component Lp1 of the illuminating light L1 and transmits an S-polarization component Ls1
Implementation Method 4
a light valve 21 that modulates illuminating light on a basis of image data to output the modulated light
Implementation Method 5
a projection lens that projects the modulated light from the light valve on a projection surface, and allows detection light to enter from a direction opposite to a travelling direction of the modulated light
Implementation Method 6
an imaging device that is disposed at a location optically conjugated with the light valve, and allows the detection light to enter through the projection lens
Implementation Method 7
a blue laser diode 11B that emits blue light LB with a wavelength of about 450 nm, a green laser diode 11G that emits green light LG with a wavelength of about 520 nm, and a red laser diode 11R that emits red light LR with a wavelength of about 640 nm
Data Source
AI summary
A projection display apparatus includes a light valve that modulates illuminating light on the basis of image data to output the modulated light, an illuminating unit including a light source, and a plurality of optical members for illumination that generate the illuminating light on the basis of light from the light source to guide the illuminating light to the light valve, a projection lens that projects the modulated light from the light valve on a projection surface, and allows detection light to enter from a direction opposite to a travelling direction of the modulated light, and an imaging device that is disposed at a location optically conjugated with the light valve, and allows the detection light to enter through the projection lens. The plurality of optical members for illumination have optical property of reducing a noise component that affects the detection light and arises inside the illuminating unit.