BACKGROUND

Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section.

Vehicles can be configured to operate in an autonomous mode in which the vehicle navigates through an environment with little or no input from a driver. Such autonomous vehicles can include one or more sensors that are configured to detect information about the environment in which the vehicle operates.

One such sensor is a light detection and ranging (LIDAR) device. A LIDAR can estimates distance to environmental features while scanning through a scene to assemble a “point cloud” indicative of reflective surfaces in the environment. Individual points in the point cloud can be determined by transmitting a laser pulse and detecting a returning pulse, if any, reflected from an object in the environment, and determining the distance to the object according to the time delay between the transmitted pulse and the reception of the reflected pulse. A laser, or set of lasers, can be rapidly and repeatedly scanned across a scene to provide continuous real-time information on distances to reflective objects in the scene. Combining the measured distances and the orientation of the laser(s) while measuring each distance allows for associating a three-dimensional position with each returning pulse. In this way, a three-dimensional map of points indicative of locations of reflective features in the environment can be generated for the entire scanning zone.

SUMMARY

In one example, a light detection and ranging (LIDAR) device is provided that includes a housing configured to rotate about an axis. The housing has an interior space that includes a transmit block, a receive block, and a shared space. The transmit block has an exit aperture and the receive block has an entrance aperture. The LIDAR device also includes a plurality of light sources in the transmit block. The plurality of light sources is configured to emit a plurality of light beams that enter the shared space through the exit aperture and traverse the shared space via a transmit path. The light beams include light having wavelengths in a wavelength range. The LIDAR device also includes a plurality of detectors in the receive block. The plurality of detectors is configured to detect light having wavelengths in the wavelength range. The LIDAR device also includes a lens mounted to the housing. The lens is configured to (i) receive the light beams via the transmit path, (ii) collimate the light beams for transmission into an environment of the LIDAR device, (iii) collect light that includes light from one or more of the collimated light beams reflected by one or more objects in the environment of the LIDAR device, and (iv) focus the collected light onto the detectors via a receive path that extends through the shared space and the entrance aperture of the receive block.

In another example, a method is provided that involves rotating a housing of a light detection and ranging (LIDAR) device about an axis. The housing has an interior space that includes a transmit block, a receive block, and a shared space. The transmit block has an exit aperture and the receive block has an entrance aperture. The method further involves emitting a plurality of light beams by a plurality of light sources in the transmit block. The plurality of light beams enter the shared space via a transmit path. The light beams include light having wavelengths in a wavelength range. The method further involves receiving the light beams at a lens mounted to the housing along the transmit path. The method further involves collimating, by the lens, the light beams for transmission into an environment of the LIDAR device. The method further involves collecting, by the lens, light from one or more of the collimated light beams reflected by one or more objects in the environment of the LIDAR device. The method further involves focusing, by the lens, the collected light onto a plurality of detectors in the receive block via a receive path that extends through the shared space and the entrance aperture of the receive block. The method further involves detecting, by the plurality of detectors in the receive block, light from the focused light having wavelengths in the wavelength range.

These as well as other aspects, advantages, and alternatives, will become apparent to those of ordinary skill in the art by reading the following detailed description, with reference where appropriate to the accompanying figures.

