Abstract: A flow cell system for an optical fluid analysis comprises a disposable flow cell having at least one flow chamber comprising a fluid pathway, and at least one pair of opposed light transmitting windows along the fluid pathway, an external flow cell holder for holding the flow cell, at least one light source, and an external detection device couplable with at least one of the flow cell holder and the flow cell for bringing the external detection device in optical communication with the flow cell, the device having at least one optical detection unit. The external detection device is configured to conduct optical measurements of the fluid that flows in the flow cell through at least one pair of windows from externally under illumination by the at least one light source.

Abstract: A display panel, a display device and a display method are provided. The display panel includes: first pixels configured to display a first image; second pixels configured to display a second image. The display panel further includes light-shielding patterns configured to shield part of light beams emitted by the second pixels.

Abstract: A display device and a display method are provided. The display device includes a plurality of repeat units and an optical layer. Each of the repeat units includes a plurality of display elements displaying a same object with different parallaxes. At least two of the display elements displaying the same object with the closest parallax are not connected with each other. The optical layer is disposed on the repeat units. The optical layer having a plurality of light transmission areas and a light non-transmission area around the light transmission areas. Each of the repeat units overlaps with two or more light transmission areas.

Abstract: A slit slider assembly for providing a plurality of slits. The slit slider assembly includes: a holder including a first channel and a pair of set screws that each has a ball partially extruding into the first channel; and a slit carrier assembly configured to be slidably disposed in the first channel and carry a slit mask that includes a plurality of slits, the slit carrier assembly including a plurality of dimples for receiving a portion of the ball. When the balls of the pair of set screws engage two dimples of the plurality of the dimples, the holder is configured to pass light through one of the plurality of slits that corresponds to the two dimples.

Abstract: An image pickup unit, an image pickup device, a picture processing method, a diaphragm control method, and program are capable of suppressing deterioration in quality of a stereoscopic picture. A parallax detection pixel receives object light by a plurality of photodetectors covered with one microlens, to generate a signal used for detecting parallax. G pixels, an R pixel, and a B pixel each receive the object light to generate a signal used for generating a planar picture. A parallax detection section detects parallax based on the signal generated by the parallax detection pixels. A 2D picture generation section generates a planar picture based on a signal generated by picture generation pixels. A 3D picture generation section adjusts a position of each object image included in the planar picture, based on the detected parallax, to generate a stereoscopic picture.

Abstract: Provided is an observation apparatus and an observation method with which it is possible to observe imaging subjects, such as cells or the like, without labeling the imaging subjects and without causing an increase in the apparatus size. Provided is an observation apparatus including: a light-source unit that emits illumination light upward from below a sample; and an image-capturing optical system that has an objective lens that collects transmitted light, which is the illumination light emitted from the light-source unit that has passed through the sample by being reflected above the sample and that captures, below the sample, the transmitted light collected by the objective lens.

Abstract: The stereoscopic image display device which displays images corresponding to each of a plurality of viewpoints includes: a stereoscopic image display panel which includes a display panel in which a plurality of pixels are arranged and a light-ray separating module provided on the display panel for separating parallax images from each of the pixels towards a plurality of N-viewpoints (N is a natural number of 2 or larger) according to the layout direction of each of the pixels; an observer position measuring unit which measures an observing position of the observer who is facing the display surface; a relative position calculating unit which calculates a relative position of the observer with respect to the stereoscopic image display panel based on the measurement result; and an image generation processing unit which generates viewpoint image by corresponding to the relative position and outputs the image towards the stereoscopic image display panel.

Abstract: A confocal optical scanner includes: a plurality of condenser elements each configured to concentrate illumination light to be applied on a sample to produce fluorescence from the sample; a plurality of optical scanning units including a plurality of openings each configured to allow the illumination light concentrated by the condenser element to pass the opening, the optical scanning units each configured to scan the sample with the illumination light that has passed through the opening; a moving mechanism configured to move the optical scanning units to select one of the optical scanning units; and an incident-angle adjusting part configured to adjust the incident angle of the illumination light incident on the optical scanning unit selected from the optical scanning units according to the selected optical scanning unit.

Abstract: A fixed aperture includes a first fixed slit and a second fixed slit which are arranged respectively in regions positioned on both sides with a moving line sandwiched therebetween. A drive aperture includes a first drive slit and a second drive slit which are arranged on both sides with the moving line sandwiched therebetween. The first fixed slit and the first drive slit are formed in an extending manner along a first line, and are arranged such that these slits communicate with each other when a shutter is at a position where the transmission of light is allowed. The second fixed slit and the second drive slit are formed in an extending manner along a second line which intersects with the first line, and are arranged such that these slits communicate with each other when the shutter is at a position where the transmission of light is allowed.

Abstract: A microscope has an aperture arrangement that, in order to limit the dimension of a light beam, comprises an aperture opening. The size of the aperture opening is adjustable with the aid of a first aperture member and a second aperture member. At least one of the two aperture members is movable relative to the other aperture member. The aperture members are spaced apart from one another when the aperture opening is closed.

Abstract: The display apparatus including a microelectromechanical (MEMS) shutter is disclosed. The MEMS shutter is shifted by the switching element in a horizontal direction corresponding to the light control area to turn on or turn off the light control area. A first slit transmits light generated from the light source to the MEMS shutter of a first substrate and a second slit of a second substrate corresponding to the first slit provides apertures by overlapping the first slit and the second slit. The apertures of the MEMS shutter are distributed on a two dimensional plane and form a geometrically symmetric pattern that are capable of enhancing light-use efficiency.

Abstract: A spectrometer design method that corrects aberration by using crossed optical paths and minor alignment, simplifies manufacture by applying the light entrance slit and aperture on opposite sides of a transparent input block, and creates a more compact footprint by placing a 45 degree mirror or right angle prism directly in front of the detector is disclosed.

Abstract: An aperture shaped to provide a narrow beam in the horizontal plane but a wider beam in the vertical plane that will provide improved image quality in spectrometers without sacrificing as much throughput as typically experienced using a reduced diameter round aperture along with a method of mounting the entrance slit and the limiting aperture on a transparent block for optical stability and ease of alignment is disclosed.

Abstract: A diaphragm device for projector includes a first gear unit, a second gear unit and two diaphragm plates. The first gear unit includes a partial circular arc portion and a gear portion with partial no tooth. The second gear unit includes a circular arc portion corresponding to the partial circular arc portion, and a pinion and a gear corresponding to the gear portion with partial no tooth. When the partial circular arc portion abuts on the circular arc portion, the gear does not rotate. When the partial circular arc portion does not abut on the circular arc portion, the gear portion with partial no tooth meshes the gear to transmit rotation of the first gear unit to the gear. The two diaphragm plates each on which a rack meshing the pinion is formed, moves in directions opposed to each other according to rotation of the pinion.

Abstract: The invention is a high-throughput multi-capillary system utilizing a 2-dimensional mask onto which the detection windows of the capillaries are lined up in alternating columns and rows. The image of the capillaries is projected onto a 2-dimensional detection system, such as a charge-coupled-detector (CCD) array. Each row and column of the capillary detection windows is imaged in a separate area of the CCD array, which results in reduced cross-talk between capillaries.

Abstract: A micro shutter device and a method of manufacturing the micro shutter device are provided. A transparent substrate is provided. A barrier is formed on the substrate to partition a unit pixel. A pattern layer is formed with a transparent material to have a transparent first pattern portion on the substrate in the unit pixel. A movable plate is arranged to face the pattern layer, has an opaque second pattern layer corresponding to a shape of the first pattern portion, and is configured to transmit light therethrough except the second pattern portion. An actuator is for moving the movable plate. Therefore, light leakage due to diffraction can be prevented, resulting in increasing contrast ratio and improving light efficiency.

Abstract: The present invention provides a light source apparatus capable of producing stable oscillation and performing high-speed wavelength sweeping over a desired wavelength range. A swept light source apparatus in which oscillation wavelength is continuously changeable is provided. The apparatus includes, inside a resonator, an optical amplification medium that amplifies light, a first device configured to disperse light emitted from the optical amplification medium and thus produce beams having different wavelengths, a second device functioning as a non-focusing optical element and configured to collimate the beams having different wavelengths resulting from the dispersion by the first device, and a selecting device configured to select a beam having a specific wavelength from among the beams collimated by the second device. The beam having the specific wavelength selected by the selecting device is fed back to the optical amplification medium.

Abstract: An aperture unit includes three or more diaphragm blades, a base plate that supports the diaphragm blades, a drive lever connected to the diaphragm blades, and an aperture motor that rotates the drive lever, wherein, in a range from a reference aperture value to a specific aperture value, a polygonal aperture is formed by aperture edges of two or more of the three or more diaphragm blades that linearly move in a first direction and an aperture edge of at least one of the three or more diaphragm blades that linearly moves in a second direction opposite to the first direction, and wherein, in a range from the specific aperture value to a closed aperture state, an aperture is formed by aperture edges of two diaphragm blades that move in opposite directions.

Abstract: The present invention provides a shutter apparatus and a drive method for the same, the shutter apparatus having functions of both a shutter apparatus for an image interception and a shutter apparatus for an aperture adjustment and being space-saving and low in costs. Within an illumination casing are provided first and second shading plates 212 and 215, first and second cammed gear 224 and 227 having a cam groove 225 and 228 respectively for driving the first shading plate 212 and the second shading plate 215 respectively. A cam shape is structured such that the rotation of a DC motor 235 (one drive source) enables the first and second shading plates 212 and 215 to drive independently. Thus, arbitrarily operating the functions of both the shutter apparatus for the image interception and the shutter apparatus for the aperture adjustment by the DC motor 235 (one shared drive source) is possible.

Abstract: A tension apparatus for extending a patterning slit sheet included in a thin film deposition apparatus that can be simply applied to produce large-sized display devices on a mass scale and that improves manufacturing yield. The tension apparatus, wherein a plurality of patterning slits are formed along a first direction in the patterning slit sheet, and distances between adjacent patterning slits are different from each other, includes: a light source disposed to face the patterning slit sheet and irradiating light toward the patterning slit sheet; a tension member combined to at least one end of the patterning slit sheet, and applying a predetermined tensile force on the patterning slit sheet; and a master glass onto which light irradiated from the light source and passed through the patterning slit sheet is projected.

Abstract: A system and method for uniform light generation in projection display systems. An illumination source comprises a light source to produce colored light, and a scrolling optics unit optically coupled to the light source, the scrolling optics unit configured to create lines of colored light from the colored light, and to scroll the lines of colored light along a direction orthogonal to a light path of the illumination source. The scrolling optics unit comprises a single light shaping diffuser to transform the colored light into the lines of colored light, an optical filter positioned in the light path after the light shaping diffuser, and a scrolling optics element positioned in the light path after the optical filter. The single light shaping diffuser is capable of simultaneously transforming colored light into lines of colored light having substantially uniform intensity to provide uniform illumination.

Abstract: An aperture unit includes three or more diaphragm blades, a base plate that supports the diaphragm blades, a drive lever connected to the diaphragm blades, and an aperture motor that rotates the drive lever, wherein, in a range from a reference aperture value to a specific aperture value, a polygonal aperture is formed by aperture edges of two or more of the three or more diaphragm blades that linearly move in a first direction and an aperture edge of at least one of the three or more diaphragm blades that linearly moves in a second direction opposite to the first direction, and wherein, in a range from the specific aperture value to a closed aperture state, an aperture is formed by aperture edges of two diaphragm blades that move in opposite directions.

Abstract: In at least one embodiment of the disclosure, a light control device includes a light blocking module to block a luminous flux passing through the light control device in a direction parallel to a system optical axis. The light blocking module includes a first and a second light blocking member. The first light blocking member includes a cutout portion at an end near a system optical axis, the first light blocking member configured so as to change a size of an area blocking the luminous flux in accordance with an opening and closing operation of the light blocking module. The second light blocking member is disposed in proximity to the first light blocking member and configured so as to increasingly block the luminous flux from passing through the cutout portion of the first light blocking member in accordance with the closing operation of the light blocking module.

Abstract: A dynamic aperture, positioned in the path of light, includes a pair of parallel blades, a connecting member, a driving member, and a motor. The projection device includes a light source configured for generating light. The connecting member is fixed to the projection device and rotatably interconnects a same side of the blades. The driving member rotatably interconnects the opposite side of the blades so that the blades, the connecting member, and the driving member constituting a variable quadrangular frame. The motor is coupled to the driving member and is configured for rotating the driving member. Rotation of the driving member and restriction of the projection device to the connection member alter dimensions of the variable quadrangular frame and accordingly adjust a gap between the blades through which the generated light passes.

Abstract: A light shielding unit, which shields a part of an exposure light with a light shielding member, includes a sensor which detects displacement of the light shielding member, a driving device which drives the light shielding member based on a detection result obtained by the sensor, a case which accommodates the sensor and the driving device, and a bellows mechanism which gas-seals the case with respect to the light shielding member. When the illumination area of the illumination light is defined, it is possible to mitigate the influence of the foreign matters and/or the heat generated from the driving mechanism.

Abstract: A transmission illumination apparatus for a microscope has an optically transparent sample mount plate on which a sample is mounted, a surface light source that projects substantially uniform illumination light toward the sample mount plate, and a light orientation member that restricts diffusion of the illumination light in relation to at least one direction.

Abstract: A planar light source of the present invention includes a light source part, a light guide part for guiding light emitted from the light source part to form planar emission of the light, and a reflector for reflecting light emitted from the light source part to allow the light to enter the light guide part. The reflector has a member for controlling the amount of reflected light capable of controlling the amount of reflected light.

Abstract: An adjustable shroud for use with a detector having an aperture for detecting electromagnetic radiation. The adjustable shroud includes a base element, a cover element and a directional shroud. The cover element and the directional shroud may be adjusted over an aperture of a detector to increase and/or decrease a detection field associated with the detector. The user is easily able to configure the adjustable shroud to block a portion of a detection field associated with the detector to eliminate unwanted environment factors.

Abstract: The invention concerns a system for projecting a digital video image sequence using a light beam capable of being generated by a source (1) on a 3D swivel joint (2), of low/medium power laser type or white light laser type. The system comprises a shutter microdisc (4) with slots (3), two rotary optical discs (5) and (7) digitally interlocked on an axis (12) with 3D swivel joints (6), generating vertical and horizontal scanning of the screen, the whole assembly terminated by a rectangular shutter (8). The display is achieved by successive reflections of the light beam on microscopic reflecting facets arranged on the surface of the discs (5) and (7).

Abstract: A laser repair system including a laser light oscillator for generating laser light, and a slit unit on which the laser light is irradiated and which includes a laser light-blocking section, a first slit section and a second slit section, wherein the laser light-blocking section of the slit unit does not transmit the laser light incident on the laser light-blocking section, and the amount of light transmitted through the first slit section is greater than that of light transmitted through the second slit section.

Abstract: Methods for measuring expansion of a test sample. One method includes establishing a diffraction slit between two blades, with the position of at least one of the blades being dependent upon the length of a test sample of material. As the temperature of the sample changes, the width of the slit changes. Light is projected through the slit onto a target and an diffraction pattern is measured. Changes in the light diffraction pattern correspond to the thermal expansion of the sample. Another method includes establishing a diffraction slit between two blades, with the position of at least one of the blades being dependent upon a length along a test sample of material. As a load is applied to the test sample, the width of the slit changes. Changes in the light diffraction pattern correspond to Young's Modulus for the sample.

Abstract: Adjustable pinhole, particularly for the illumination beam path and/or detection beam path of a laser scanning microscope, wherein the pinhole is defined by foil edges which are adjustable relative to one another, and at least two foils, each with at least one straight edge, are advantageously arranged relative to one another and/or connected to one another in such a way that their edges describe an L-shape and the L-shaped connection pieces are arranged on one another in such a way that they define a rhombic or square light passage and they are moved relative to one another for adjusting the pinhole.

Abstract: The invention relates to a transmitted-light base (1) for illuminating an object (15) for imaging through a zoom microscope (21), the transmitted-light base (1) comprising an integrated light source (3) having an associated electrical power regulation system (31) for generating a suitable radiation flux, and means (5, 6), capable of being added downstream, for generating a specified spectral intensity distribution. To allow compensation for brightness changes of low dynamic range, such as those occurring in particular during zooming, a continuously controllable mechanical brightness regulator (4) is proposed which is activatable by means of an associated adjustment device (41) in such a way that the illumination intensity of the transmitted-light base (1) is controllable with no change in the spectral intensity distribution.

Abstract: Adjustable pinhole, particularly for the illumination beam path and/or detection beam path of a laser scanning microscope, wherein the pinhole is defined by foil edges which are adjustable relative to one another, and at least two foils, each with at least one straight edge, are advantageously arranged relative to one another and/or connected to one another in such a way that their edges describe an L-shape and the L-shaped connection pieces are arranged on one another in such a way that they define a rhombic or square light passage and they are moved relative to one another for adjusting the pinhole.

Abstract: An optical measurement device capable of improving optical spectrum measurement accuracy without the need to structurally decrease a slit width. A diffraction grating for dispersing measurement light into respective different wavelengths is rotated in a given direction to produce diffracted light of selected wavelengths. A focusing lens converges the diffracted light to produce a converged beam. A slit control section varies the slit width at a constant scan speed to open or close the slit, thereby varying the passing bandwidth for the converged beam. A light receiving/measuring section receives the light passed through the slit, obtains a level function indicative of the power level of the received light that varies with change in optical frequency, and differentiates the level function by the scan speed to reproduce the spectrum profile of the measurement light.

Abstract: An optical slit comprises two blades 40,42 which define a slit between them, each blade being independently movable. This enables both the slit position and the slit width to be adjusted. The slit may be aligned with the center of a light beam by aiming the light beam at a detector, traversing at least one edge of the slit across the beam path, measuring the intensity of transmitted light at the detector for each position of the slit, and feeding back a signal which adjusts the slit position for maximum light throughput. The width on the optical slit may be selected by placing the slit in the path of the light beam and measuring the light transmitted at the detector, calculating the percentage of light transmitted for that slit width and feeding back a signal which adjusts slit width to obtain the desired amount of light throughput.

Abstract: A parallax barrier comprises evenly spaced groups of slits. Each group comprises two or more slits which are evenly spaced and the groups are spaced with a period which is greater than the product of the number of slits in each group and the slit period in each group. Such a barrier may be used with a spatial light modulator having columns of pixels whose structure cooperates with the barrier structure to provide a wider angle between views in a multiple view display, such as an autostereoscopic 3D display or a display providing two or more different views to two or more observers.

Abstract: Heat generation is inhibited in a polarized light generating optics system in a projector. A liquid crystal projector includes: lens arrays 140, 150 that generate partial light beams from a light beam emitted from a light source; and a polarized light generating optics system 160 that generates polarized light, which is to be supplied to liquid crystal light valves, from the partial light beams. The polarized light generating optics system 160 separates s-polarized light and p-polarized light by polarization separating films 64a. The s-polarized light is reflected from reflecting films 64b and is emitted directly. The p-polarized light is converted into s-polarized light by a selective phase difference plate 66 and is emitted therefrom. The polarized light generating optics system 160 is equipped with light shielding surfaces 62b that shield light from entering into the reflecting films 64b.

Abstract: Device (1) and method for delimiting a field (3) impinged with light from a light source (2), particularly on the surface of an optical element (4) and/or sample (5), having a slit diaphragm (6) including a slit height (7) and a slit width (8), which includes first and second linearly movable slides (9, 9?), positioned parallel to one another on two separate parallel lines, which are movable at least partially symmetrically to one another in relation to an optical axis (10), each of the two slides (9, 9?) including at least one optical opening (11, 11?), which—for continuous adjustment of at least the slit height (7) or the slit width (8)—may be positioned at least partially on the optical opening (11?, 11) of the neighboring slide (9?, 9) in the region of the optical axis (10).

Abstract: When a video signal is inputted to a projector (10) through a video input terminal, a luminance peak value of an image of the video signal is detected by an image-analyzing circuit (61) to be outputted to a CPU (71). A gain-adjusting circuit (63) adjusts a luminance signal in the video signal based on a command from the CPU (71). The CPU (71) determines a gain adjustment amount based on the luminance peak value of the image obtained by the image-analyzing circuit (61) and outputs the result to the gain-adjusting circuit (63). For instance, when the luminance peak value (Ip) of the image is 50% of the upper limit (Imax) thereof, a gain-adjusting amount AG is doubled. In this case, an illuminating light volume of a light valve (44a) has to be reduced to 50%, which is achieved by light-attenuation by a light-source lamp (21) and an open/close light shield (23).

Abstract: There is provided a variable width optical slit mechanism capable of controlling the width of a slit with high accuracy in wide range of temperatures. A pair of conductive carriages is movably mounted on a conductive guide rail in the state that the carriages are not in contact with the guide rail by use of insulative rolling elements, or alternatively, a pair of conductive carriages is movably mounted on an insulative guide rail by use of conductive rolling elements. A pair of slit forming members is mounted to the pair of carriages, respectively. An elastic force is given to the carriages for energizing them such that they move toward each other, thereby to always bring the slit forming members into contact with each other to make the width of a slit zero. When a slit is formed, the carriages move away from each other against the elastic force.

Abstract: A projector includes an array of micromirror light modulators and a projector light source for generating an illumination light beam along an optical path. An elongated rectilinear illumination aperture is defined at a first location along the optical path, with one or more elongated regions having a long dimension parallel to the axis. An elongated rectilinear pupil aperture is defined at an output pupil with one or more elongate pupil regions having a long dimension parallel to the axis.

Abstract: Described herein is a spectrophotometer having an inlet slit associated to which is at least one electrostatic-film shutter.

Abstract: An optical scanning apparatus includes a rotatable polygonal mirror for deflecting first and second laser beams, which are incident on the polygonal mirror at diff(rent positions with respect to a rotational direction of the polygonal mirror; a first optical member for transmitting the first laser beam; a second optical member for transmitting the second laser beam; a laser beam blocking member, disposed between the first optical member and the second optical member, for blocking the first laser beam reflected by the first optical member to prevent the first laser beam reflected by the first optical member from being incident on the second optical member.

Abstract: A parallax barrier comprises evenly spaced groups of slits. Each group comprises two or more slits which are evenly spaced and the groups are spaced with a period which is greater than the product of the number of slits in each group and the slit period in each group. Such a barrier may be used with a spatial light modulator having columns of pixels whose structure cooperates with the barrier structure to provide a wider angle between views in a multiple view display, such as an autostereoscopic 3D display or a display providing two or more different views to two or more observers.

Abstract: An optical slit comprises two blades 40,42 which define a slit between them, each blade being independently movable. This enables both the slit position and the slit width to be adjusted. The slit may be aligned with the centre of a light beam by aiming the light beam at a detector, traversing at least one edge of the slit across the beam path, measuring the intensity of transmitted light at the detector for each position of the slit, and feeding back a signal which adjusts the slit position for maximum light throughput. The width on the optical slit may be selected by placing the slit in the path of the light beam and measuring the light transmitted at the detector, calculating the percentage of light transmitted for that slit width and feeding back a signal which adjusts slit width to obtain the desired amount of light throughput.

Abstract: A variable slit width device for a spectroscope which can be used in a narrow space, be widely variable, and be set in slit width with high accuracy. The variable slit width device includes a pair of freely rotatable rotary parts for pressing inclined guide parts of a pair of slit holders, pressing parts for supporting the pair of rotary parts, and linear guides having guide parts formed at the lower surfaces thereof and extending horizontally in a direction crossing with guide rails at right angles. The pressing parts are fixed to the linear guides, the guide rails are fitted to the guide parts of the linear guides, feed nuts are fixed to the pressing parts, feed screws are engaged with the feed nuts. Bearings are provided for rotatably supporting the feed screws, preload springs for preloading the feed nuts and the feed screws, a slit driving part for rotatably driving the feed screws, and a housing part for fixing thereto the guide rails, the bearings and the motor.

Abstract: An imaging system is disclosed that includes an illumination source, a modulator and a variable Fourier diaphragm. The illumination source produces a first illumination field having a first frequency and a second illumination field having a second frequency. The modulator receives the first illumination field and the second illumination field, and produces a first modulated illumination field and a second modulated illumination fields. The variable Fourier diaphragm selectively passes one of the first modulated illumination field and the second modulated illumination field.

Abstract: A lensless focusing device for receiving an unfocused laser beam and creating a desired output pattern of laser profiles. The focusing device includes a pair of wedge plates oriented at a reflective angle relative to the projection axis of the input laser beam. The focusing device generates an output pattern having a plurality of spaced laser profiles. The laser profiles include a series of fixed laser profiles and a series of adjustable laser profiles. Rotation of the focusing device about the projection axis of the input laser beam moves the adjustable laser profiles relative to the fixed laser profiles. Multiple focusing devices can be used in series with each other to generate an output pattern having a grid shape in which points on the grid are movable upon rotation of either focusing device.

Abstract: There is provided a variable width optical slit mechanism capable of controlling the width of a slit with high accuracy in wide range of temperatures. A pair of conductive carriages is movably mounted on a conductive guide rail in the state that the carriages are not in contact with the guide rail by use of insulative rolling elements, or alternatively, a pair of conductive carriages is movably mounted on an insulative guide rail by use of conductive rolling elements. A pair of slit forming members is mounted to the pair of carriages, respectively. An elastic force is given to the carriages for energizing them such that they move toward each other, thereby to always bring the slit forming members into contact with each other to make the width of a slit zero. When a slit is formed, the carriages move away from each other against the elastic force.