A product conveyance apparatus includes an actuator, a movement portion, a first position detection portion, a second position detection portion, and a controller. The controller performs a process of causing the actuator not holding a product to move to a predetermined position, detecting the position of the actuator and storing the position as a first position, a process of causing the actuator to move on a basis of a movement instruction value and hold the product, causing the actuator holding the product to move to the predetermined position, detecting the position of the product held by the actuator, and storing the position as a second position, and a process of correcting and updating the movement instruction value on a basis of difference between the first position and the second position.

A workpiece conveyance apparatus having: a conveyance path on which the workpiece moves; a gas flotation section that gas-floats the workpiece over the conveyance path; a movable holding section that holds the workpiece to move on the conveyance path along with the workpiece; and a treatment region conveyance path that is located on the conveyance path, and has a treatment region where predetermined treatment for the workpiece is performed, wherein the movable holding section has at least two or more holding sections along a movement direction of the conveyance path, each of the holding sections is capable of switching between release of holding and holding for the workpiece during movement of the workpiece, operation for releasing holding of the workpiece by the holding section on the treatment region conveyance path, and holding the workpiece on the conveyance path other than the treatment region conveyance path.

The invention relates to a method for producing an optical element from glass, wherein a portion of glass or a glass blank is blank-pressed, in particular on both sides, to form the optical element, wherein the optical element is then placed on a transport element and passes through a cooling path with the transport element, without the optical surface of the optical element being touched.