Pathlength matched beam splitter and method and apparatus for assembly

A device, comprising

• a first precision holding device configured to hold a first prism and place a first alignment target adjacent to a face of the first prism;
• a second precision holding device configured to hold a second prism such that a diagonal of the second prism is parallel to a diagonal of the first prism and to place a second alignment target adjacent to a face of the second prism;
• an adjustment device configured to adjust relative positions of the first and second holding devices;
• and
• an observation mechanism configured to observe a first light path originating at the first alignment target and a second light path originating at the second alignment target.

A method, comprising the steps of:

• selecting a first triangular prism comprising a first diagonal;
• selecting a second triangular prism comprising a second diagonal;
• abutting the triangular prisms at the diagonals in a beam splitting configuration;
• and
• fixing the triangular prisms in beam splitter pathlength matched positions.

A method, comprising the steps of:

• selecting a prism;
• selecting an optical component;
• depositing a beam splitting layer on a surface of at least one of the prism and the optical component;
• abutting the prism to an optical component at the beam splitting layer to form a beam splitter having a single internal reflection at the beam splitting layer such that an input light is split into a first split beam reflected by the beam splitting layer and a second split beam passing the beam splitting layer;
• adjusting the relative positions of the prism and the optical component until the first split beam and the second split beam are pathlength matched;
• and
• setting the prism and optical component in the split beam pathlength matched position.

A method, comprising the steps of:

• selecting a prism;
• selecting an optical component;
• depositing a beam splitting layer on a surface of at least one of the prism and the optical component;
• abutting the prism to an optical component at the beam splitting layer to form a beam splitter that splits an incoming light beam into a first spit beam and a second split beam;
• adjusting the relative positions of the prism and the optical component until the first split beam and the second split beam are pathlength matched;
• setting the relative positions of the prism and the optical component in the beam splitter at the split beam pathlength matched position;
• and
• installing the beam splitter in a video projection device.

A method, comprising the steps of:

• selecting a prism;
• selecting an optical component;
• depositing a beam splitting layer on a surface of at least one of the prism and the optical component;
• abutting the prism to a side of the optical component at the beam splitting layer to form a beam splitter that splits an incoming light beam into a first spit beam and a second split beam;
• adjusting the relative positions of the prism and the optical component until the first split beam and the second split beam are pathlength matched;
• and
• setting the relative positions of the prism and the optical component in the beam splitter at the split beam pathlength matched position;
• wherein the step of adjusting the relative positions of the prism and the optical component comprises overlapping ends of the diagonal and the side of the optical component by an amount proportional to a difference in dimensions between the prism and the optical component.