Abstract: A surveying instrument includes a sighting telescope optical system, a distance measuring system which outputs first data, a phase detection autofocus system which and outputs second data, and an AF driver which moves a focusing lens of the sighting telescope optical system to bring the sighting object into focus in accordance with one of the first data and the second data. A surveying instrument is also disclosed, which includes a sighting telescope and an AF drive unit which is provided separately from the sighting telescope, wherein the AF drive unit can be mounted to and dismounted from a body of the surveying instrument.

Abstract: A survey point indicating instrument, for recognizing a line of sight visually, includes a collimating lens, two light sources being positioned so that optical axes of the two light sources intersect each other on an optical axis of the collimating lens at a focal point of the collimating lens; a driving circuit for controlling light emissions of the two light sources independently from each other; and a light shield plate having a slit, and positioned between the focal point and the two light sources so that light rays emitted from each of the two light sources to travel in an area between the optical axes are allowed to pass through the slit while other light rays emitted from each of the two light sources are cut off by the light shield plate to prevent the other light rays from traveling outside the area between the optical axes.

Abstract: A surveying instrument includes a sighting telescope optical system, a distance measuring system which outputs first data, a phase detection autofocus system which and outputs second data, and an AF driver which moves a focusing lens of the sighting telescope optical system to bring the sighting object into focus in accordance with one of the first data and the second data. A surveying instrument is also disclosed, which includes a sighting telescope and an AF drive unit which is provided separately from the sighting telescope, wherein the AF drive unit can be mounted to and dismounted from a body of the surveying instrument.

Abstract: A surveying instrument includes a surveying instrument body rotatable about each of a vertical axis and a horizontal axis; and a first collimator optical system and a second collimator optical system each of which is positioned in the surveying instrument body to collimate the surveying instrument relative to a survey point, a viewing angle of the second collimator optical system being greater than a viewing angle of the first collimator optical system. A first collimating operation is performed with the first collimator optical system after a second collimating operation is performed with the second collimator optical system.

Abstract: An electronic distance meter includes a sighting telescope optical system having an objective lens for sighting an object, and an optical distance meter which includes a light-transmitting optical system for transmitting a measuring light toward the object via the objective lens, and a light-receiving optical system for receiving a portion of the measuring light which is reflected by the object. The light-transmitting optical system includes a light-shield mask having a translucent portion to define a beam profile of the measuring light. The translucent portion comprises a filter having an uneven density, light transmittance of a central portion of the filter being greater than light transmittance of a peripheral portion of the filter.

Abstract: A surveying instrument includes a surveying instrument body which is rotatable about vertical and horizontal axes and has a telescope optical system for collimating the surveying instrument relative to a survey point; a collimator optical system for projecting first light rays toward the survey point and for receiving the first light rays reflected at the survey point; an auto-collimating system which rotates the surveying instrument body to position the survey point on an optical axis of the telescope optical system; a distance measuring optical system for projecting second light rays toward the survey point and for receiving the second light rays reflected at the survey point; and a distance measuring device for calculating a distance from the surveying instrument to the survey point. The optical axes of the collimator optical system and the distance measuring optical system are offset from each other.

Abstract: A surveying instrument includes a sighting telescope optical system, a distance measuring system which outputs first data, a phase detection autofocus system which and outputs second data, and an AF driver which moves a focusing lens of the sighting telescope optical system to bring the sighting object into focus in accordance with one of the first data and the second data. A surveying instrument is also disclosed, which includes a sighting telescope and an AF drive unit which is provided separately from the sighting telescope, wherein the AF drive unit can be mounted to and dismounted from a body of the surveying instrument.

Abstract: An integral transmitter-receiver optical communication apparatus, including: a transmitter-receiver device including: a transmitter having a laser source for emitting a laser beam modulated in accordance with a transmission information signal, a receiver having a position detecting sensor and a light receiving element each of which receives a complementing modulated laser beam transmitted from a complementing transmitter, and a beam splitting device for splitting the modulated laser beam and the complementing modulated laser beam into two separate laser beams; a telescopic optical system for transmitting the modulated laser beam emitted by the laser source, and for receiving the complementing modulated laser beam transmitted from the complementing transmitter, the telescopic optical system including a first afocal optical system; a light beam deflecting device positioned between the telescopic optical system and the transmitter-receiver device, wherein the light beam deflecting device is controlled in accorda

Abstract: A variable-focus lens system includes a negative front lens group, and a positive rear lens group. The focal length of the variable-focus lens system is varied by changing the distance between the front and said rear lens groups. The lens system satisfies the following conditions: −3.0<fx/Fw<−2.5 3.0<fy/Fw<3.5 wherein fx designates the focal length of the front lens group, which is less than zero; fy designates the focal length of the rear lens group, which is greater than zero; and Fw designates the focal length of the entire variable-focus lens system at the short focal length extremity.

Abstract: A surveying instrument includes a sighting telescope having an objective lens and an eyepiece; a Porro-prism erecting system; a semitransparent surface formed on a reflection surface of the Porro-prism erecting system; a beam splitting prism adhered to the semitransparent surface; and a focus detecting device which detects a focus state from a correlation between a pair of images respectively formed by two light bundles which are respectively passed through two different pupil areas of the objective lens and passed through two separate areas on the semitransparent surface. An area of a surface of the beam splitting prism which is adhered to the semitransparent surface is smaller than an effective area of the reflection surface of the Porro-prism erecting system. The semitransparent surface and the beam splitting prism are positioned so that the two light bundles are incident on the semitransparent surface at the same incident angle.

Abstract: A surveying instrument which incorporates a magnetic incremental rotary encoder includes a rotary magnetic drum provided on an outer peripheral surface thereof with a multi-pole magnetized layer having a plurality of equally-divided magnetized divisions, a pair of magnetic sensors located on opposite sides of said rotary magnetic drum so that each of said pair of magnetic sensors faces said multi-pole magnetized layer, and at least one magnet, positioned in the vicinity of at least one of said pair of magnetic sensors, for reducing an error in detection of said magnetic incremental rotary encoder.

Abstract: An incremental rotary encoder includes a rotary portion, a first sensor and a second sensor, the first and second sensors being arranged so as to be opposite from each other with respect to the axis of the rotary portion. The second sensor is offset from the first sensor so that the phase of output voltage of the second sensor advances or delays with respect to the phase of output voltage of the first sensor by &pgr;/X, wherein “X” represents a real number of one or more than one.

Abstract: A surveying instrument having an AF apparatus, provided with a focusing lens and a collimation telescope, includes a focus detector for detecting a focus state through the collimation telescope, and a controller for moving the focusing lens of the collimation telescope to a focal position, based on the focus state detected by the focus detector. The surveying instrument includes a single focus mode at which only one detection of the output of the focus detector and only one control operation of the controller based on the detected output are carried out, and a continuous focus mode at which a plurality of detections of the output of the focus detector and a plurality of control operations of the controller based on the detected outputs are sequentially carried out, the single focus mode and the continuous mode being selectively performed.

Abstract: An electronic distance meter includes a sighting telescope optical system having an objective lens for sighting an object, and an optical distance meter which includes a light-transmitting optical system for transmitting a measuring light toward the object via the objective lens, and a light-receiving optical system for receiving a portion of the measuring light which is reflected by the object. The light-transmitting optical system includes a light-shield mask having a translucent portion to define a beam profile of the measuring light. The translucent portion comprises a filter having an uneven density, light transmittance of a central portion of the filter being greater than light transmittance of a peripheral portion of the filter.

Abstract: An electronic distance meter includes a sighting telescope having an objective lens for sighting an object; a reflection member positioned behind the objective lens; an optical distance meter which includes a light-transmitting optical system for transmitting a measuring light via the reflection member and the objective lens, and a light-receiving optical system for receiving light which is reflected by the object, subsequently passed through the objective lens and not interrupted by the reflection member; a beam-diameter varying device, provided in association with the light-transmitting optical system, for varying a beam diameter of the measuring light; and a controller which varies the beam diameter via the beam-diameter varying device in accordance with a distance from the object to the electronic distance meter.

Abstract: An incremental rotary encoder having first and second sensors which each output two sine wave signals having a phase difference of 90 degrees while a rotary member of the incremental rotary encoder rotates. The incremental rotary encoder includes an absolute-zero-index detecting device, provided for the first sensor; at least one binary coding circuit which codes each of the two sine wave signals and the zero index signal into a corresponding binary signal; a holding device for holding the level data of the binary signal of each sine wave signal output from the second sensor when the absolute-zero-index detecting device outputs the zero index signal; and a controller for determining whether the phase of the two sine wave signals output from the second sensor advances or delays with respect to the phase of the two sine wave signals output from the first sensor.

Abstract: A surveying instrument which incorporates a magnetic incremental rotary encoder includes a rotary magnetic drum provided on an outer peripheral surface thereof with a multi-pole magnetized layer having a plurality of equally-divided magnetized divisions; and at least two magnetic sensors, each of which detects a magnetic field generated by the multi-pole magnetized layer therefrom. Each of the at least two magnetic sensors detects a variation in the magnetic field due to a rotation of the rotary magnetic drum to measure an angle of rotation of the rotary magnetic drum, and the at least two magnetic sensors are arranged so that two of the at least two magnetic sensors are offset from each other to have a phase angle of an odd-numbered pitch angle therebetween.

Abstract: A surveying machine that automatically adjusts an optical axis includes a sighting optical system for sighting an object, a light-transmitting optical system that transmits a beam for surveying, radiated from a light source, to the object, a deviation detector, and an optical axis adjuster. The deviation detector detects a deviation between a first optical axis corresponding to the sighting optical system and a second optical axis corresponding to the light-transmitting optical system. The optical axis adjuster automatically adjusts at least one of the first optical axis and the second optical axis so as to correct the deviation.