Pulse-modulated laser-based near-eye display

Enacted in a computer of a near-eye display device, a near-eye display method comprising:

• parsing a digital image;
• controlling a matrix of electronically controllable pixel elements of a spatial light modulator (SLM) configured to receive emission from a laser and direct the emission in spatially modulated form to a pupil-expansion optic, wherein the matrix is controlled such that the spatially modulated form of the emission projects an optical image corresponding to the digital image,
• causing a drive circuit to drive periodic current including a train of current pulses through a gain structure while the optical image is projected, the current pulses having a predetermined pulse width selected to broaden the emission relative to an unmodulated emission of the laser, and
• increasing or decreasing a separation between the current pulses of the predetermined pulse width, so as to control an average duty cycle of the periodic current and thereby provide setpoint power in a primary-color band.

A near-eye display device comprising:

• a pupil-expansion optic;
• a laser having a gain structure and configured for emission in a primary-color band;
• a drive circuit coupled operatively to the laser;
• a spatial light modulator (SLM) having a matrix of electronically controllable pixel elements, the SLM being configured to receive the emission from the laser and direct the emission in spatially modulated form to the pupil-expansion optic;
• and
• coupled operatively to the drive circuit and the SLM, a computer configured to:
• parse a digital image,
• control the matrix of pixel elements such that the spatially modulated form of the emission projects an optical image corresponding to the digital image,
• cause the drive circuit to drive periodic current including a train of current pulses through the gain structure while the optical image is projected, the current pulses having a predetermined pulse width of twenty nanoseconds or shorter, selected to broaden the emission relative to an unmodulated emission of the laser, and
• increase or decrease a separation between the current pulses of the predetermined pulse width, so as to control an average duty cycle of the periodic current and thereby provide setpoint power in the primary-color band,
• wherein the laser is one of a plurality of lasers of a field-sequential color display, wherein pulse-modulated drive current is supplied to each of the plurality of lasers, and wherein the computer is configured to control the average duty cycle for the pulse-modulated drive current supplied to each of the plurality of lasers to provide color balance.