Abstract: Enhanced probe cards, for testing unpackaged semiconductor die including numerous discrete devices (e.g., LEDs), are described. The die includes anodes and cathodes for the LEDs. Via a single touchdown event, the probe card may simultaneously operate each of the LEDs. The LEDs' optical output is measured and the performance of the die is characterized. The probe card includes a conductive first contact and another contact that are fabricated from a conformal sheet or film. Upon the touchdown event, the first contact makes contact with each of the die's anodes and the other contact makes contact with each of the die's cathodes. The vertical and sheet resistance of the contacts are sufficient such that the voltage drop across the vertical dimension of the contacts is approximately an order of magnitude greater than the operating voltage of the LEDs and current-sharing between adjacent LEDs is limited by the sheet resistance.

Abstract: Probe cards for probing highly-scaled integrated circuits are provided. A probe card includes a backplane and an array of probes extending from the backplane. Each of the probes includes a cantilever member and a probe tip. A first end of the cantilever member is coupled to the backplane, such that the cantilever member extends from the backplane. The probe tip extends from a second end of the cantilever member. The probes are fabricated from semiconductor materials. Each probe is configured to transmit electrical signals between the backplane and a device under test (DUT), via corresponding electrodes of the DUT. The probes are highly-scaled such that the feature size and pitch of the probes matches the highly-scaled feature size and pitch of the DUT's electrodes. The probes comprise atomic force microscopy (AFM) probes that are enhanced for increased electrical conductivity, elasticity, lifetime, and reliability.

Abstract: A head-mounted display (HMD) including multiple layered display panels. The HMD may include a first display panel to display a first image, and a second display panel positioned in front of the first display panel to at least partially overlap with the first display panel. The second display panel may include a display substrate, and a plurality of light emitting diodes (LEDs) positioned on the display substrate. The plurality of LEDs display a second image. The display substrate and the plurality of LEDs are transparent for the first image to be visible through the second display panel.

Abstract: Methods and apparatus (100) for profiling a beam of a light emitting semiconductor device. The apparatus comprises a light emitting semiconductor device (102) comprising an active region (108) formed on a substrate (104) and configured to generate light when a suitable electrical current is applied to contacts on an upper surface of the device and a light emitting surface (110) defined by a lower surface of the substrate opposite the contacts. The apparatus further comprises a transmission medium (112) comprising a first surface (114) in contact with at least part of the light emitting surface of the semiconductor device and a diffusion surface (116), opposite the first surface, and configured to diffuse light emitted from the micro-LED and transmitted through the transmission medium.

Abstract: A Light emitting diode (LED) includes a mesa structure, a light emitting source within the mesa structure, and a primary emission surface on a side of the LED opposed to a top of the mesa structure. The light emitting source is configured to emit light anisotropically in a first direction perpendicular to a second direction of emission of the light from the LED at the primary emission surface.

Abstract: A probe card includes a conductive body, an insulation block, and a plurality of conductive microsprings. The insulation block covers at least one side of the body and at least partially encloses the microsprings. A first end of each microspring is connected to the conductive body and a second end is exposed from the insulation block. In operation, the probe card is moved onto one or more semiconductor devices to be tested. As the probe card is moved toward the semiconductor devices, the second ends of the conductive microsprings come into contact with contact pads on the semiconductor devices. The insulation block encloses the microsprings, which prevents the microsprings from buckling or making contact with each other. As a result, the probe card produces fewer false positives and false negatives during the testing process.

Abstract: Methods and apparatus for use in the manufacture of a display device including pixels. Each pixel includes a plurality of sub-pixels, each sub-pixel configured to provide light of a given wavelength. The method may include: performing, using a pick up tool (PUT), a first placement cycle comprising picking up first light emitting diode (LED) dies, and placing a first LED die on a substrate of the display device at a location corresponding to a sub-pixel the display device. The method further includes performing one or more subsequent placement cycles comprising picking up a second LED die, and placing the second LED die on the substrate of the display device at a second location corresponding to the sub-pixel of the display device. Multiple first and second LED dies may be picked and placed during each placement cycle to populate each pixel of the display device to provide redundancy of LED dies at each sub-pixel.

Abstract: A vortex polarizer converts light having azimuthal polarization emitted at a light emitting surface of a light emitting diode (LED) into a converted light having linear polarization. The vortex polarizer includes a distribution of fast axes that vary as a function of azimuth angle. Each fast axis rotates a portion of the light having the azimuthal polarization to a portion of the converted light having linear polarization. The vortex polarizer may include linear photoalignment polymer (LPP) aligned to define the distribution of fast axes.

Abstract: A Light emitting diode (LED) includes a mesa structure, a light emitting source within the mesa structure, and a primary emission surface on a side of the LED opposed to a top of the mesa structure. The light emitting source is configured to emit light anisotropically in a first direction perpendicular to a second direction of emission of the light from the LED at the primary emission surface.

Abstract: A lithography system includes an electron source, a lens, and a stencil mask. The electron source emits a beam of electrons. The lens converts the emitted beam of electrons into a diffuse beam of parallel electrons. The stencil mask is positioned between the lens and a semiconductor wafer with an electron-sensitive resists. The stencil mask has a pattern to selectively pass portions of the diffuse beam of parallel electrons onto the electron-sensitive resist of the wafer.

Abstract: A micro-LED, ?LED, comprising: a substantially parabolic mesa structure; a light emitting source within the mesa structure; and a primary emission surface on a side of the device opposed to a top of the mesa structure; wherein the mesa structure has an aspect ratio, defined by (H2*H2)/Ac, of less than 0.5, and the ?LED further comprises a reflective surface located in a region from the light emitting source to the primary emission surface, wherein the reflective surface has a roughness, Ra, less than 500 nm.

Abstract: A ?LED device comprising: a substrate and an epitaxial layer grown on the substrate and comprising a semiconductor material, wherein at least a portion of the substrate and the epitaxial layer define a mesa; an active layer within the mesa and configured, on application of an electrical current, to generate light for emission through a light emitting surface of the substrate opposite the mesa, wherein the crystal lattice structure of the substrate and the epitaxial layer is arranged such that a c-plane of the crystal lattice structure is misaligned with respect to the light emitting surface.

Abstract: Embodiments relate to a light emitting structure including a light emitting diode, a first contact, and a second contact. The light emitting diode includes a body of transparent semiconductor material with a top surface and a light emitting region below the top surface. The light emitting region emits light in response to current passing through the light emitting region; the emitted light passes through the body of the light emitting diode. The first contact is connected to the top surface of the body and has a spiral shape to induce an electromagnetic field. The electromagnetic field shapes the light emitted from the light emitting region and passes through the body of the light emitting diode. The second contact is connected to a surface of the light emitting structure. A voltage difference can be applied across the first contact and second contact to generate the current through the light emitting region.

Abstract: A display panel for concurrent video output and eye position tracking. The display panel includes a substrate, a plurality of visible light emitting diodes (LEDs) positioned on a side of the substrate, and a plurality of light detectors positioned on the side of the substrate. The visible LEDs transmit quasi-collimated visible light propagating away from the side of the substrate. The light detectors capture invisible light propagating toward the side of the substrate, reflected from an eye of the user. In some embodiments, non-visible LEDs are formed on the side of the substrate. The visible LEDs, light detectors, and non-visible LEDs may be arranged to form pixels of the display panel. The quasi-collimated light emitted from the visible LEDs reduces spread into beam paths of the invisible light between the non-visible LEDs and the light detectors.

Abstract: A head-mounted display (HMD) including multiple layered display panels. The HMD may include a first display panel to display a first image, and a second display panel positioned in front of the first display panel to at least partially overlap with the first display panel. The second display panel may include a display substrate, and a plurality of light emitting diodes (LEDs) positioned on the display substrate. The plurality of LEDs display a second image. The display substrate and the plurality of LEDs are transparent for the first image to be visible through the second display panel.

Abstract: Methods and apparatus for use in the manufacture of a display device including pixels. Each pixel includes a plurality of sub-pixels, each sub-pixel configured to provide light of a given wavelength. The method may include: performing, using a pick up tool (PUT), a first placement cycle comprising picking up first light emitting diode (LED) dies, and placing a first LED die on a substrate of the display device at a location corresponding to a sub-pixel the display device. The method further includes performing one or more subsequent placement cycles comprising picking up a second LED die, and placing the second LED die on the substrate of the display device at a second location corresponding to the sub-pixel of the display device. Multiple first and second LED dies may be picked and placed during each placement cycle to populate each pixel of the display device to provide redundancy of LED dies at each sub-pixel.

Abstract: A micro-LED, ?LED, comprising: a substantially parabolic mesa structure; a light emitting source within the mesa structure; and a primary emission surface on a side of the device opposed to a top of the mesa structure; wherein the mesa structure has an aspect ratio, defined by (H2*H2)/Ac, of less than 0.5, and the ?LED further comprises a reflective surface located in a region from the light emitting source to the primary emission surface, wherein the reflective surface has a roughness, Ra, less than 500 nm.

Abstract: Methods and apparatus for use in the manufacture of a display device including pixels. Each pixel includes a plurality of sub-pixels, each sub-pixel configured to provide light of a given wavelength. The method may include: performing, using a pick up tool (PUT), a first placement cycle comprising picking up first light emitting diode (LED) dies, and placing a first LED die on a substrate of the display device at a location corresponding to a sub-pixel the display device. The method further includes performing one or more subsequent placement cycles comprising picking up a second LED die, and placing the second LED die on the substrate of the display device at a second location corresponding to the sub-pixel of the display device. Multiple first and second LED dies may be picked and placed during each placement cycle to populate each pixel of the display device to provide redundancy of LED dies at each sub-pixel.

Abstract: A micro-LED, ?LED, comprising: a substantially parabolic mesa structure; a light emitting source within the mesa structure; and a primary emission surface on a side of the device opposed to a top of the mesa structure; wherein the mesa structure has an aspect ratio, defined by (H2*H2)/Ac, of less than 0.5, and the ?LED further comprises a reflective surface located in a region from the light emitting source to the primary emission surface, wherein the reflective surface has a roughness, Ra, less than 500 nm.

Abstract: A ?LED device comprising: a substrate and an epitaxial layer grown on the substrate and comprising a semiconductor material, wherein at least a portion of the substrate and the epitaxial layer define a mesa; an active layer within the mesa and configured, on application of an electrical current, to generate light for emission through a light emitting surface of the substrate opposite the mesa, wherein the crystal lattice structure of the substrate and the epitaxial layer is arranged such that a c-plane of the crystal lattice structure is misaligned with respect to the light emitting surface.