Tilt Detection via Optical Pattern on Pivot Member

The patent replaces the traditional mechanical encoder system with an optical detection system. A light source projects light onto an angle detection pattern formed on the pivot member, and a photodetection element receives the reflected light to detect the rotation angle. This optical substitution eliminates the need for large mechanical encoders while achieving high tilt detection accuracy through optical pattern recognition and photodetection.

The patent uses an angle detection pattern (a visual copy or representation of angular position) formed on the pivot member instead of a physical mechanical encoder. The pattern consists of radial lines or markings that represent angular positions, and the photodetection element reads this optical copy to determine the tilt angle, replacing the need for complex mechanical encoding structures.

The patent concentrates the angle detection information into a localized angular region on the pivot member where the angle detection pattern is formed. The photodetection element only needs to detect patterns within this specific angular range rather than covering a large area, allowing for a small photodetection element size while maintaining high detection accuracy through focused local pattern recognition.

The patent transitions from a two-dimensional spatial encoding (large mechanical encoder盘面) to a one-dimensional angular pattern on a compact pivot member. The angle detection pattern uses radial lines or markings arranged in an angular dimension around the pivot axis, allowing the photodetection element to detect tilt angles through angular pattern recognition rather than spatial position detection, enabling miniaturization without sacrificing accuracy.