The range of operating angles of a position transducer is widened, and its signal-to-noise ratio is improved. The position transducer includes a light source and a detector including at least one pair of photodiodes (PDs) disposed on a predetermined circle. The detector receives light emitted from the light source to output a signal varying depending on the areas of regions where the light is received on two PDs forming a pair. The PDs are formed on separate chips, respectively, and the chips are disposed on a substrate so that one or more pairs of PDs surround the entirety of a predetermined region and have an annular shape as a whole.

A micro device transfer tool and methods of operation are described. In an embodiment, the micro device transfer tool includes an articulating transfer head assembly capable of six degrees of motion. A miniatured camera assembly may be secured near the point of contact for the articulating transfer head assembly to aid in system alignment. In an embodiment, an encoder system is described for alignment of a micro pick up array and target substrate using complementary concentric grating patterns. In an embodiment a miniaturized position sensor design is described for sensing position of various system components during alignment or pick and place processes.

A micro device transfer tool and methods of operation are described. In an embodiment, the micro device transfer tool includes an articulating transfer head assembly capable of six degrees of motion. A miniatured camera assembly may be secured near the point of contact for the articulating transfer head assembly to aid in system alignment. In an embodiment, an encoder system is described for alignment of a micro pick up array and target substrate using complementary concentric grating patterns. In an embodiment a miniaturized position sensor design is described for sensing position of various system components during alignment or pick and place processes.

An image based opto-electronic encoder for a joint, the encoder having a reading head for the first part of the joint and an optical system, comprising a ball lens for the second part of the joint. The ball lens has a front surface transparent for measuring light and an at least partially reflective, structured back surface. The ball lens has -with respect to the measuring light- a refractive index of at least approximately two or an equal radially varying refractive index, such that a bundle of measuring light rays reflected inside the ball lens from a point of the back surface of the ball lens forms at least approximately a parallel bundle after getting refracted at the front surface of the ball lens. The reading head and the ball lens are rotatable relative to each other in at least two degrees of freedom.

An image based opto-electronic encoder for a joint, the encoder having a reading head for the first part of the joint and an optical system, comprising a ball lens for the second part of the joint. The ball lens has a front surface transparent for measuring light and an at least partially reflective, structured back surface. The ball lens has -with respect to the measuring light- a refractive index of at least approximately two or an equal radially varying refractive index, such that a bundle of measuring light rays reflected inside the ball lens from a point of the back surface of the ball lens forms at least approximately a parallel bundle after getting refracted at the front surface of the ball lens. The reading head and the ball lens are rotatable relative to each other in at least two degrees of freedom.

A damper assembly has a longitudinal axis and includes a damper housing with a side wall portion and an end wall portion defining a damping chamber containing a quantity of damping fluid. A photon source and a photon receptor are operatively disposed in optical communication with the non-gaseous damping fluid in the damping chamber. The photon source is operable to direct a photon through the non-gaseous damping fluid toward an associated target surface. The photon receptor is operable to receive the photon reflected off the associated target surface through the non-gaseous damping fluid. A sensor suitable for such use as well as spring and damper assemblies and suspension systems are also included.

A damper assembly has a longitudinal axis and includes a damper housing with a side wall portion and an end wall portion defining a damping chamber containing a quantity of damping fluid. A photon source and a photon receptor are operatively disposed in optical communication with the non-gaseous damping fluid in the damping chamber. The photon source is operable to direct a photon through the non-gaseous damping fluid toward an associated target surface. The photon receptor is operable to receive the photon reflected off the associated target surface through the non-gaseous damping fluid. A sensor suitable for such use as well as spring and damper assemblies and suspension systems are also included.

A vertical cavity surface emitting laser includes a gain layer configured to generate light; a distributed Bragg reflector below the gains layer; and a meta structure reflector above the gain layer and comprising a plurality of nano structures having a sub wavelength dimension.

A vertical cavity surface emitting laser includes a gain layer configured to generate light; a distributed Bragg reflector below the gains layer; and a meta structure reflector above the gain layer and comprising a plurality of nano structures having a sub wavelength dimension.

A system is provided for detecting a forcer misalignment, e.g., due to forcer loss of registration (FLR), in a wafer prober used for electrical testing of a semiconductor wafer. The system includes an optical sensor system including a transmitter and receiver affixed to the forcer or to a reference structure (e.g., the prober platen), and a reflector affixed to the other one of the forcer or reference structure. The transmitter emits radiation toward the reflector, which reflects the radiation toward the receiver. The receiver detects the reflected radiation, and generates an output signal indicating the quantity of received radiation. Alignment monitoring circuitry is configured to identify a misalignment of the forcer relative to the reference structure (e.g., platen) based on the output signal generated by the receiver, and in response, output an alert signal, e.g., to suspend operations of the prober and/or display an error notification to an operator.