A method for adjusting the magnification scale of an optical imaging device for exposing or inspecting substrates is provided. The optical imaging device includes a first optical element group, which includes a plurality of first optical elements in an imaging beam path. The method includes replacing optical elements of the first optical element group in the imaging beam path by optical elements of a second optical element group for the purposes of adjusting the magnification scale. The first optical element group includes two reflecting optical elements with first optical parameters, which define a first Petzval sum. The second optical element group includes two reflecting optical elements with second optical parameters, which define a second Petzval sum. The value of the first Petzval sum is at least substantially identical to the value of the second Petzval sum.

Methods and apparatus for supporting zoom operations using a plurality of optical chain modules, e.g., camera modules, are described. Switching between use of groups of optical chains with different focal lengths is used to support zoom operations. Digital zoom is used in some cases to support zoom levels corresponding to levels between the zoom levels of different optical chain groups or discrete focal lengths to which optical chains may be switched. In some embodiments optical chains have adjustable focal lengths and are switched between different focal lengths. In other embodiments optical chains have fixed focal lengths with different optical chain groups corresponding to different fixed focal lengths. Composite images are generate from images captured by multiple optical chains of the same group and/or different groups. Composite image is in accordance with a user zoom control setting. Individual composite images may be generated and/or a video sequence.

Methods and apparatus for supporting zoom operations using a plurality of optical chain modules, e.g., camera modules, are described. Switching between use of groups of optical chains with different focal lengths is used to support zoom operations. Digital zoom is used in some cases to support zoom levels corresponding to levels between the zoom levels of different optical chain groups or discrete focal lengths to which optical chains may be switched. In some embodiments optical chains have adjustable focal lengths and are switched between different focal lengths. In other embodiments optical chains have fixed focal lengths with different optical chain groups corresponding to different fixed focal lengths. Composite images are generate from images captured by multiple optical chains of the same group and/or different groups. Composite image is in accordance with a user zoom control setting. Individual composite images may be generated and/or a video sequence.

A method for designing an optical system for providing reliable, robust and successful realization of a distortion variation function is presented. In a preferred embodiment, the proposed distortion variation optical system includes at least two non-symmetrical elements, which are moving in the transverse direction. The proposed freeform lens contains two transmissive refractive surfaces. The freeform elements designed with this method have preferably a flat surface and a non-symmetrical freeform surface. The two plano-surfaces are preferably made to face each other, so that a miniature camera can be offered. The value of the non-symmetrical freeform surface is used to produce variable optical power when the two freeform elements undergo a relative movement in the vertical direction. Using this method, an optical system with an active distortion, smaller form factor, and better imaging quality can be obtained.

A zoom lens is provided which has at least one front optical group with fixed optical power, adapted to receive rays from an observed object, at least one rear optical group with fixed optical power, adapted to convey the rays towards an image plane of a sensor, a lens opening positioned between the front optical group and the rear optical group, a front adaptive lens positioned between the at least one front optical group and the lens opening, and a rear adaptive lens positioned behind the lens opening. The front and rear adaptive lenses are controllable to vary the respective optical power to adjust focal length, magnification, and working distance of the zoom lens.

The objective lens has multiple focal lengths within a focal length interval and a relatively small focal-length ratio in a range from 1.05 to 2.75, and a travel-to-focal-length ratio in a range from 0.05 to 0.4. The objective lens has three main lens groups that define a negative-positive-positive optical system configuration. The first lens group has a rearward lens sub-group that is axially movable for focusing so that the lens length stays the same during focusing. The objective lenses use optical compensation rather than mechanical compensation to move between the design focal lengths each having an in-focus image. This simplifies operation while increasing reliability and reducing cost. A small set of one or more of the objective lenses can be used to replace a large set of prime lenses each having a single focal length, so that fewer lenses are needed to cover the same focal length span.

The objective lens has multiple focal lengths within a focal length interval and a relatively small focal-length ratio in a range from 1.05 to 2.75, and a travel-to-focal-length ratio in a range from 0.05 to 0.4. The objective lens has three main lens groups that define a negative-positive-positive optical system configuration. The first lens group has a rearward lens sub-group that is axially movable for focusing so that the lens length stays the same during focusing. The objective lenses use optical compensation rather than mechanical compensation to move between the design focal lengths each having an in-focus image. This simplifies operation while increasing reliability and reducing cost. A small set of one or more of the objective lenses can be used to replace a large set of prime lenses each having a single focal length, so that fewer lenses are needed to cover the same focal length span.

A zoom control method is provided, including: determining a midpoint of a connecting line of touch points located on both sides of an object to be close-up; determining a pixel vector formed from the midpoint of the connecting line to a center point of a screen; converting the pixel vector into an angle vector based on a conversion relationship between a diagonal angle of view of a current focal length range and a diagonal pixel of an image sensor of a camera system; and controlling the object to be close-up being moved to the center point of the screen based on the angle vector.

A zoom control method is provided, including: determining a midpoint of a connecting line of touch points located on both sides of an object to be close-up; determining a pixel vector formed from the midpoint of the connecting line to a center point of a screen; converting the pixel vector into an angle vector based on a conversion relationship between a diagonal angle of view of a current focal length range and a diagonal pixel of an image sensor of a camera system; and controlling the object to be close-up being moved to the center point of the screen based on the angle vector.

An apparatus and a method for powder bed fusion additive manufacturing involve a multiple-chamber design achieving a high efficiency and throughput. The multiple-chamber design features concurrent printing of one or more print jobs inside one or more build chambers, side removals of printed objects from build chambers allowing quick exchanges of powdered materials, and capabilities of elevated process temperature controls of build chambers and post processing heat treatments of printed objects. The multiple-chamber design also includes a height-adjustable optical assembly in combination with a fixed build platform method suitable for large and heavy printed objects. A side removal mechanism of the build chambers of the apparatus improves handling and efficiency for printing large and heavy objects. Use of a wide range of sensors in the apparatus and by the method allows various feedback to improve quality, manufacturing throughput, and energy efficiency.