On-Axis Holographic Sight

A sighting device for assisting with aiming of an instrument, comprising:

• a housing configured to engage with the instrument;
• a light source in the housing;
• an image generating element in the housing configured to receive light from the light source and generate image information including a reticle pattern;
• an input light coupling optical element in the housing configured to receive the image information from the image generating element;
• an imageguide optically coupled to the input light coupling optical element, the input light coupling optical element being configured to direct the image information into the imageguide;
• an output light coupling optical element optically coupled to the imageguide and configured to receive the image information from the imageguide and project a virtual image viewable to a user of the instrument and appearing at a distance from the instrument;
• a controller;
• a motion sensor on the instrument in communication with the controller;
• a first light sensor in communication with the controller, wherein the first light sensor is positioned in a front of the sighting device and directed such that light reflected from a target is received when the sighting device is aimed at the target and provides a signal representative of target brightness to the controller;
• and
• a second light sensor in communication with the controller and positioned to receive ambient light proximate the sighting device,
• wherein the controller is configured to activate the sighting device based on movement of the instrument detected by the motion sensor, and
• wherein the controller is configured to modulate brightness of the virtual image based on light conditions determined from both the first light sensor and the second light sensor.