CN2452037Y

CN2452037Y - Focal plane imaging double-wave range separating device

Info

Publication number: CN2452037Y
Application number: CN 00259498
Authority: CN
Inventors: 汤学新
Original assignee: Shanghai Institute of Technical Physics of CAS
Current assignee: Shanghai Institute of Technical Physics of CAS
Priority date: 2000-12-07
Filing date: 2000-12-07
Publication date: 2001-10-03
Anticipated expiration: 2010-12-07

Abstract

The utility model provides a double-waveband separating device used before focal plane imaging systems. In the utility model, two fan filters have different wavebands, are installed in a disc and driven by a brushless type direct current motor and alternately go into a light path before a focal plane; a frame signal in the output of the focal plane is used as a reference for controlling the rotation speed and the phase of a motor for causing the time of the two filters going into the light path to keep strict synchronization with the frame signal for separating the two wavebands. The utility model is suitable for the temperature range within-20DEG. C to +50DEG. C and can also be used for separating multiple wavebands.

Description

Focal plane imaging two waveband tripping device

The utility model relates to light beam and decomposes or combination technique, particularly a kind of preceding two waveband tripping device of focal plane imaging system that is used in.

Be in the imaging system of detector with the focal plane device, often needing to obtain the target emanation amount of two above wave bands.If obtain multiwave radiant quantity with many table apparatus, then not only volume and weight increases progressively greatly, and its cost also significantly improves.Technical ten minutes need be to the tripping device of the different-waveband of light beam.

The purpose of this utility model is to provide a kind of preceding two waveband tripping device of focal plane imaging system that is used in.

The purpose of this utility model reaches like this: the fan-shaped optical filter of two different-wavebands is housed on the filter disc, drives filter disc by brshless DC motor, make optical filter alternately enter light path.With the frame signal in the focal plane device output is reference signal, makes the frame signal of rotating speed of motor and phase place and focal plane device output keep the synchronous of strictness by control circuit, realizes the separation of light beam wave band.

The utility model description of drawings is as follows:

Fig. 1 is the structural representation of the utility model two waveband tripping device.

Fig. 2 is the front elevation of the optical filtering disk in the utility model two waveband tripping device.

Fig. 3 is the control circuit block diagram in the utility model two waveband tripping device.

Fig. 4 is the control circuit figure in the utility model two waveband tripping device, and the dotted line among the figure is rectified corresponding with the circuit block of Fig. 3.

Below in conjunction with accompanying drawing the utility model is made sets forth in detail:

This device is installed in the fan-shaped optical filter 101 and 102 of two different-wavebands on the optical filtering disk 1, is driven by brshless DC motor 3, makes two tablet filters alternately enter light path.Detect the tach signal and the phase signal of optical filtering disk by the photoelectric tube 2 that straddles optical filtering disk 1 edge, deliver to control circuit 4.As reference signal, make rotating speed of motor and phase place and frame signal keep strict synchronism with the frame signal in the focal plane device output by control circuit.

For using focal plane device as detector, more than the common 30mm of its clear aperture.So the width of optical filter must be greater than 30mm.Optical filtering disk 1 external diameter is 194mm, thickness 4mm.Optical filter 101 and 102 thickness are 2mm, and width is 40mm, and segment angle is 160 °.The nearly 100 gram cm of moment of inertia that the optical filtering disk is total ²Because two optical filters vary in weight, and must handle through counterweight, reduce its unevenness as far as possible.

For phase place and rotating speed to optical filtering disk 1 detect and control, 9 apertures have been opened at the edge of disk.Wherein 8 circumference according to dish are provided with every 45 ° of equalizations.Draw signal with photoelectric tube 2.The optical filtering disk rotates a circle, and 8 pulses are just arranged, and per second 15 changes 120 of pulses.With this as rate signal f _SpeedAnother aperture 104 is opened an intersection at two optical filters.Optical filtering disk per second 15 changes, and can obtain 15 pulses of per second.Phase signal f as the optical filtering disk _Phase9 apertures are positioned on the same radius, with a pair of photoelectric tube 2 detecting signals, and again with delay and NAND gate circuit, can be with f _SpeedAnd f _PhaseTake out respectively.

Control signal is the frame signal of focal plane device output.Per second 30 frames.Two wave bands, a frame is every a frame.The rotating speed of optical filtering disk is that per second 15 changes revolution two frames.Switch in the field blanking interval of two optical filters between two frames.The frame signal two divided-frequency is become 15H, as phase reference signal.

Phase loop 402 is to use phase signal f _PhaseBehind two divided-frequency, become phase reference signal to send in the phase detector with frame signal, draw phase error voltage.The height of this voltage has been represented f _PhasePhase place and frame signal phase place poor, amplify the phase place that self-regulation motor is removed in the back negative feedback, make the phase locking of optical filtering disk in the phase place of frame signal.

Phase detector is made up of delay B, sawtooth wave, sampling B, and its principle is such: reference signal is delivered to sawtooth wave form circuit, form the rising oblique wave of linear change in time, deliver to sampling B.f _PhaseBurst pulse is as sampling pulse.Sampling B comes at sampling pulse and constantly opens, and the rising oblique wave is delivered to the maintenance capacitor C in the amplitude in this moment ₂In.After the sampling pulse, sampling gate is closed.Capacitor C ₂On current potential remain unchanged.The height of its current potential has reflected f _PhasePhase differential with frame signal.We are placed on the centre of rising oblique wave with sampling pulse, with the current potential got this moment as the correct phase place of filter disc.Change soon as motor, sampling pulse is leading, and the current potential of getting is at the first half of rising oblique wave, and its current potential is lower, and the FEEDBACK CONTROL motor lowers rotating speed.On the contrary, change slowly as motor, sampling pulse lags behind, and the current potential of getting is at the latter half of rising oblique wave, and its current potential is higher, and the FEEDBACK CONTROL motor makes faster rotational speed.Thereby reach the purpose of automatic adjustment phase place.

Phase loop 402 contains two divided-frequency U12A; Postpone B U13A, U14A; Sawtooth wave C8; Sampling BU6A.

For stablizing motor speed, and when start, make motor reach stable rotating speed fast, be provided with speed loop 401.Rate signal f _Speed,, produce another row pulse f ' through postponing _SpeedIt and f _SpeedPhase differential fix.But it and next f _SpeedThe phase differential of signal pulse, then the speed with motor speed changes.Use f ' _SpeedForm the rising oblique wave, f _SpeedAs the sampling burst pulse, then keep capacitor C ₁On the current potential obtained reflected the speed of motor speed.Similar to the phase detector principle in the phase loop.Motor speed is remained on its intrinsic speed, reach the purpose of automatic adjustment rotating speed.Simultaneously, speed loop also has anti-jamming capacity.

Speed loop 401 contains and postpones and Sheffer stroke gate U1A, U2A, U3A; Postpone A U7A, U8A; Oblique wave C12; Sampling A U9A.

Control action by speed loop 401 and phase loop 402 adds temperature-compensation circuit 403D3, D4, after voltage/frequency is changed 404 U17 and power amplifier 405 U18, Q11, Q12, Q13, with rotating speed of motor and phase locking in the phase place of frame signal.Thereby make the phase place of filter disc and the phase place of frame signal keep reaching the purpose that two waveband is separated synchronously.

The utility model has following beneficial effect:

1) because employing driven by Brush-Less DC motor, therefore required micro power consumption. The optical filtering circle of this device The nearly 100 gram cm of its rotary inertia of dish load² The power supply of its motor and circuit board is+15V1A ,-15V1A, Be total to 30W.

2) this device is equally applicable to multiband.Triband for example, four wave bands.As long as make frame signal two divided-frequency among Fig. 3 into three frequency division, four frequency divisions, optical filter makes three into, four by two.

3) this device has high control precision.Filter disc rotates a circle needs 66.67ms.Control accuracy reaches ± 02ms in, promptly a week ± 3 ‰ in.

4) this device has temperature compensation, and its temperature limit is-20 ℃-+50 ℃.

5) this device successfully is applied in and stares on the formula infra-red imaging radiometer.This radiometer is to use the infrared CCD focal plane device as detector, and its service band is 1～5 micron, requires to obtain to be respectively the infrared radiation image of 1～3 micron and 3～5 microns two wave bands.Be output as video, per second 30 frames.Clear aperture 30mm.Adopt this device successfully two wave bands to be separated.

Claims

1. a focal plane imaging two waveband tripping device comprises optical filtering disk (1), optical filter (101), (102), drive motor (3), photoelectric tube (2) and control circuit (4); It is characterized in that;

A) put on optical filtering disk (1) the fan-shaped optical filter (101) of two different-wavebands and (102), drive by brshless DC motor (3), make two tablet filters alternately enter light path, detect the tach signal and the phase signal of optical filtering disk by the photoelectric tube (2) that straddles optical filtering disk (1) edge, deliver to control circuit (4), as reference signal, make rotating speed of motor and phase place and frame signal keep strict synchronism with the frame signal in the focal plane device output by control circuit;

B) said optical filter (101) and (102) its segment angle are 160 °;

C) said optical filtering disk (1), be to have two scallop holes in the diameter symmetria bilateralis, the disk that its segment angle is 160 °, the perforate position is more smaller than optical filter, so that two tablet filters to be installed, be equipped with 9 apertures (103) and (104) in the same radius in the edge of disk; Wherein 8 apertures (103) are according to the circumference equal distribution, and promptly the interval is 45 °; Another aperture (104) is at an intersection of two optical filters;

D) said photoelectric tube (2) detects the tach signal and the phase signal of filter disc (1) by aperture (103) and (104);

E) said control circuit (4) is by speed loop (401) and phase loop (402), temperature compensation (403), and voltage/frequency conversion (404), power amplification (405) five parts are formed.

2. according to claim 1 focal plane imaging two waveband tripping device, it is characterized in that: said phase loop 402 contains two divided-frequency U12A, postpones B U28A, U14A, sawtooth wave, sampling BU6A.

3. according to claim 1 focal plane imaging two waveband tripping device, it is characterized in that: said speed loop 401 contains and postpones Sheffer stroke gate U1A, U2A.Postpone A U7A, U8A, oblique wave D1 diode, sampling A U9A.