Optical system of laser ceilometer
Technical field
The present invention relates to optical system of laser ceilometer.
Background technology
Laser ceilometer is the active photoelectric detection equipment with optical maser wavelength work, and equipment comprises generating laser and laser pickoff two big opticses, and each optics configuration one cover optical system is called optical transmitting system and receiving optics respectively.Optical transmitting system is used for the collimation of the divergent beams of laser radiation, and receiving optics is used for pinching by the laser echo signal of cloud layer scattering.From the optical imaging concept analysis; " thing " of optical transmitting system is the light-emitting area of lasing source, this " thing " by optical transmitting system became " as ", should be on the cloud layer bottom surface of unlimited distance; Therefore; Optical transmitting system should be " collimation " type optical system, that is is transformed into the optical system of parallel beam to divergent beams, and the light-emitting area of generating laser should be placed near the focal plane of optical transmitting system.From the optical imaging concept analysis; " thing " of receiving optics launched the searchlighting hot spot of laser beam on the cloud layer bottom surface, this " thing " be received that optical system becomes " as ", should be on the focal plane of receiving optics; Therefore; Receiving optics should be " photographic lens " type optical system, that is is transformed into the optical system of convergent beam to parallel beam, and the photosurface of laser pickoff should be placed near the focal plane of receiving optics.
The optical system of laser ceilometer is made up of optical elements such as lens, and the lens with focusing function are by the light transmissive material manufacturing, and two optical surfaces of definite gauge, caliber size and definite curvature are arranged.The line of the center of curvature of two optical surfaces is defined as the optical axis of lens, and the root mean square equivalence center line of the center of curvature of same optical system, a plurality of lens is defined as the optical axis of optical system.The spatial orientation of laser ceilometer optical transmitting system optical axis is determining the direct of travel of Laser emission light beam, and the spatial orientation of receiving optics optical axis is determining that the return signal of which direction is surveyed.The relative position of optical transmitting system optical axis and receiving optics is arranged, that is the total arrangement scheme of optical system of laser ceilometer, and performance level, technical difficulty and cost cost for laser ceilometer have decisive significance.
Existing laser ceilometer product adopts that optical transmitting system optical axis and receiving optics optical axis detached parallel arrange more sends out, the release optical system of contracture; This scheme layout is as shown in Figure 1; Optical transmitting system and receiving optics have lens separately separately; Just need two cover lens, two nested structures, then the scheme layout of this optical system has deficiencies such as structure dispersion, big and heave and lens element demand are many.
Summary of the invention
The purpose of this invention is to provide the light in a small amount optical system of laser ceilometer of a kind of compact conformation, body.
Optical system of laser ceilometer of the present invention; Comprise generating laser, laser pickoff, optical transmitting system and receiving optics; The shared cover optical lens of said optical transmitting system and receiving optics; At this cover optical lens and tilting between focal plane below it dichroic reflector arranged, this dichroic reflector is positioned on the optical axis of said optical lens, and said generating laser and laser pickoff are arranged at respectively on the focal plane of optical transmitting system and receiving optics.
Between dichroic reflector and laser pickoff, be provided with filter plate, this filter plate is positioned on the receiving optics optical axis and with this optical axis is vertical and is provided with.
Said dichroic reflector is divided into two with the back segment of optical axis; Article one, optical axis continues to advance along former rectilinear direction;, optical axis 90 ° of left and right sides steering horizontals of turning back are made as optical transmitting system with the optical system at straight line optical axis place, and another broken line optical system is made as receiving optics.
Said dichroic reflector is divided into two with the back segment of optical axis; Article one, optical axis continues to advance along former rectilinear direction;, optical axis 90 ° of left and right sides steering horizontals of turning back are made as receiving optics with the optical system at straight line optical axis place, and another broken line optical system is made as optical transmitting system.
Said dichroic reflector becomes 45 tilting with lens axis.
The reflectivity of said dichroic reflector is 38%.
The optical system that the present invention is used for laser ceilometer makes optical transmitting system and the shared lens of receiving optics, a nested structure; Make total system compact conformation, body light in a small amount; Cheap; The use of dichroic reflector is divided into two with the back segment of lens axis; Form two system focal planes of emission coefficient and receiving system simultaneously, generating laser and laser pickoff are located at respectively on the focal plane of optical transmitting system and receiving optics, solved the spatial coherence problem of device installation site.
Further, the setting of filter plate is in order to reduce the interference of dichroic reflector to laser pickoff.
Through evidence, the reflectivity of dichroic reflector 38% has good effect.
Description of drawings
Fig. 1 is existing the release optical system of contracture;
Fig. 2 is an optical system of laser ceilometer of the present invention.
Embodiment
The possibility of optical system of laser ceilometer total arrangement comprises " sending out contracture leaves " and " send out and fold one " amphitypy.So-called to send out contracture release, that is optical transmitting system and receiving optics have lens separately separately, and the optical axis of optical transmitting system and the optical axis of receiving optics is separated from one another, parallel arrangement is as shown in Figure 1.So-called sending out folds a type, that is optical transmitting system and the shared cover lens of receiving optics, and the optical transmitting system optical axis overlaps with receiving optics optical axis part section each other, only near the device installation site time, just is divided into two, and is as shown in Figure 2.
Optical system of laser ceilometer of the present invention comprises generating laser, laser pickoff, optical transmitting system and receiving optics, and optical transmitting system and the shared cover optical lens of receiving optics; It is an optical lens here; For fear of the installation site space mutually mutual interference of generating laser, must the dichroic reflector that become 45 with lens axis be arranged in that optical lens is tilting between the focal plane below with it, and this dichroic reflector is positioned on the optical axis of said optical lens with laser pickoff; This dichroic reflector is divided into two with the back segment of optical axis; Article one, optical axis continues to advance along former rectilinear direction, and an optical axis 90 ° of left and right sides steering horizontals of turning back are here with the optical axis 90 ° of steering horizontals of turning back left; So just the focal plane with same lens becomes two by one; Generally speaking, the optical system that the straight line optical axis is belonged to is made as optical transmitting system, and another broken line optical system is made as receiving optics; Generating laser and laser pickoff are arranged at respectively on the focal plane of optical transmitting system and receiving optics; Thereby solved the spatial coherence problem of device installation site, between dichroic reflector and laser pickoff, be provided with filter plate, this filter plate is positioned on the receiving optics optical axis and with this optical axis is vertical and is provided with.
Shown in Figure 2 sending out folds a type optical system; The divergent beams that generating laser sends are through dichroic reflector directive optical lens; Pass the warp of this optical lens and press narrow parallel laser light beam directive cloud layer; By the back scattered parallel beam of cloud layer behind optical lens, through the filtering post-concentration of the reflection of dichroic reflector and filter plate in laser pickoff, to realize the survey cloud level purpose of laser ceilometer.
Certainly the position of optical transmitting system and receiving optics can exchange; The optical system at broken line optical axis place is made as optical transmitting system; The optical system at straight line optical axis place is made as receiving optics; Then generating laser and laser pickoff are arranged at respectively on the focal plane of optical transmitting system and receiving optics; The emission light beam that generating laser sends directive optical lens after the reflection of dichroic reflector, pass this optical lens through pressing narrow parallel laser light beam directive cloud layer, by the back scattered parallel beam of cloud layer behind optical lens; After the filtering of filter plate, converge at laser pickoff along straight line, can realize the side cloud level purpose of laser ceilometer equally.
The dichroic reflector of tiltedly putting is to send out the important optical element that folds a type optical system of laser ceilometer.Dichroic reflector is determining the proportion of utilization of Laser emission beam energy and laser pick-off beam energy to distribute to the inverse ratio performance thoroughly of laser emission.The reflectivity of dichroic reflector is high more, and the utilization factor of Laser emission beam energy is low more, but high more with the utilization factor of laser pick-off beam energy.Evidence, for the laser ceilometer application scenario, about 38% reflectivity has better effect.
Deficiencies such as two lens of the present invention and the needs that excite the release optical system of contracture, two nested structures, volume weight are bigger are compared, and send out the advantage that folds a type optical system to be: only need lens, a nested structure; Compact conformation, body are light, cheap in a small amount.