CN209280859U - A kind of highly sensitive high jamproof photodiode detector - Google Patents

Abstract

A kind of highly sensitive high jamproof photodiode detector of the utility model, is related to photodiode detection technique field.It is characterized in that including the circuit module of setting, photocell and photoelectricity stall, optical fiber and fibre-optical splice, lens and lens mount, adjusting nut, heat preservation isolation and output terminal etc. in metal shielding box.The utility model keeps photodiode compact, cost is lower than photomultiplier tube, high sensitivity and anti-interference be better than photomultiplier tube characteristic, it uses high-precision power supply to make circuit mode connection through high-precision linear voltage-stablizer for the low-pass filtered module of the linear Voltage stabilizing module of rectification filtering module and be to obtain more preferably performance, femto-ampere grade amplifier is used to make symmetrical circuit design for core；Using the light guidance mode with optical fiber and lens subassembly, it is that raising sensitivity and anti-interference are made contributions that the high impedance transmission line technical measures in metal shielding box and with deposited copper form encirclement from photronic pin to input, which are arranged in, in all sensing units.

Description

A kind of highly sensitive high jamproof photodiode detector

Technical field

The utility model relates to photodiode detection technique fields, refer specifically to a kind of highly sensitive high jamproof photoelectricity Diode detector.

Background technique

In chromatography and spectral class detecting instrument field, it is related to Uv and visible light detection device and relatively generallys use photoelectricity two Pole pipe or photomultiplier tube.Compact can be accomplished using photodiode, cost is more much lower than photomultiplier tube, and Sensitivity is also not a halfpenny the worse, also superior to photomultiplier tube in terms of anti-interference.Further, it is examined specific to using photodiode It surveys, and is divided into reverse bias open-drain output and is more commonly used across resistance amplifying circuit.Meanwhile in the preposition amplification of chromatographic apparatus electricity The first order on road, it is ultralow input bias current operational amplifier that traditional, which uses AD549JHZ for core amplifier composition,.Cause (8 Lead Metal Can) is encapsulated to belong to To-99, it is oversized for board design, and to reduce junction capacity effect It should also require input pin hanging, these are all unfavorable for the welding of patch integrated circuit and working service.Although the device price is high It is expensive, it, for a long time can only be as the first choice of first order amplifying circuit, because of design difficulty itself because being substituted without more suitable device It is larger, and the device is more demanding to the shielding design of circuit board, but tends not to reach what producer was declared in practical application Technical indicator.

Utility model content

The purpose of the utility model is to overcome missing of the existing technology and deficiencies, propose a kind of highly sensitive highly resistance The photodiode detector of interference.

To realize highly sensitive and high anti-interference ability, the utility model is made as follows in terms of circuit design and structure It improves:

First, to improve sensitivity.In terms of circuit design, firstly, using high-precision power supply for rectification filtering module The linear low-pass filtered module of Voltage stabilizing module makees circuit mode connection through high-precision linear voltage-stablizer.Circuit design core uses ADI company newest femto-ampere grade amplifier.Secondly, it is directed to the special application field of chromatography and spectrum, to obtain more preferably performance, It is designed using symmetric circuit.

Second, to improve anti-interference.Firstly, being arranged all sensing units in metal shielding box.Secondly, with deposited copper Form surrounds the high impedance transmission line etc. from photronic pin to input.

A kind of highly sensitive high jamproof photodiode detector of the utility model, it is characterized in that, metallic shield Include the circuit module of setting, photocell and photoelectricity stall, optical fiber and fibre-optical splice, lens and lens mount in box, adjusts spiral shell Mother, heat preservation isolation and output terminal etc..

The circuit module includes high-precision power supply, and two-stage amplifying circuit is connected with circuit mode；The two-stage amplification Circuit includes that the trans-impedance amplifier of first order measurement photodiode is connected with the voltage follower that the second level carries out buffering isolation Composition.

Further, according to using the monochromator of chromatography and spectral instrument, relatively advanced mostly uses double-beam system, connects By two photodiodes of the dual-beam, it should which performance is consistent as far as possible, environment of accepting is consistent, photoelectric conversion and circuit output Unanimously.Then to light source, monochromator, temperature, power supply, the homologous interference of amplifying circuit bring, under the conditions of better symmetrical performance More preferably performance is obtained, specific explanations are (fixed using lambert Bill by the control and calculating of rear class AD circuit and MCU Rule), be embodied in later period instrument performance index be exactly the basic principle for stablizing straight baseline, accordingly, circuit is taken completely Symmetrical structure.

Metal shielding box is used, although using more scheme, the utility model on pre-amplification circuit is anti-interference Improvement be to increase metal shielding box new function, including optical fiber interface and lens regulatory function, interface also use Special seal and shielding component in turn ensure the space air-tightness (isolation of metal shielding box while converging light energy Property), preferable protection is played vulnerable to stray light and temperature interference to photocell.

Metal shielding box is provided with aperture and introduces optical fiber, and light energy is more concentrated and can to the design of optical path With more flexible.

The emergent light face of optical fiber is fixed on the concavees lens on the inside of metal shielding box, then converges on photocell, Ke Yigeng The convergence light energy of concentration reduces the bandwidth of light, improves the pure of light so as to use narrower slit in optical path early period Degree.

The high impedance line surrounded from photronic pin to input is set, and feedback resistance and feedback capacity are connected to high impedance Node, along the protective layer extended around passive element, the protective layer is to apply copper form.

In conclusion the utility model in circuit design, uses high-precision power supply linear for rectification filtering module The low-pass filtered module of Voltage stabilizing module is made circuit mode connection through high-precision linear voltage-stablizer and to obtain more preferably performance, is used Femto-ampere grade amplifier is that core constitutes symmetric circuit design etc.；Using the light guidance mode with optical fiber and lens subassembly, and by institute There is sensing unit to be arranged in metal shielding box and surrounded with deposited copper form the high impedance transmission line from photronic pin to input Etc. technical measures be to improve sensitivity, high anti-interference ability makes contributions.

Detailed description of the invention

Fig. 1 is a kind of highly sensitive high jamproof photodiode detector structural schematic diagram of the utility model；

Fig. 2 is the linear power source circuit schematic diagram of the utility model embodiment；

Fig. 3 is the two-stage amplifying circuit schematic diagram of the utility model embodiment.

Specific embodiment

Below in conjunction with drawings and examples, the utility model will be further described

The utility model is a kind of highly sensitive high jamproof photodiode detector (as shown in Fig. 1), special Point is, metal shielding box 1 includes the interior circuit module 3 set, photocell 11 and photoelectricity stall 10, optical fiber 4 and fibre-optical splice 5, Lens 6 and lens mount 8, adjusting nut 7, heat preservation isolation 2 and output terminal 9.

The circuit module 3 includes high-precision power supply 31, and two-stage amplifying circuit 32 is connected with circuit mode；The two-stage Trans-impedance amplifier and the second level of the amplifying circuit 32 including first order measurement photodiode carry out the voltage follow of buffering isolation Device connection composition.

The high-precision power supply 31 is the low-pass filtered module of the linear Voltage stabilizing module of rectification filtering module through high-precision Linear voltage regulator makees circuit mode connection (as shown in Fig. 2).

The two-stage amplifying circuit 32 includes that the trans-impedance amplifier of first order measurement photodiode and the second level are delayed The voltage follower of punching isolation connects composition, using full symmetric structure (as shown in Fig. 3).

The preamplifier is to use the high-accuracy power management module of ADI company for amplifying circuit power supply, the first order Amplifying circuit is using advanced femto-ampere grade trans-impedance amplifier (TIA, trans-impedance amplifier) ADA4530-1；

The second level voltage follower is made of OP27.

Embodiment takes the encapsulation of SOIC_N (R-8) minitype paster, and reasonable price is particularly suitable for that extremely low input is required to bias The application of electric current and low input follows manufacturers instructions handbook in board design and pays attention to protection ring and protective layer and company Connection interface can be designed ideal chromatographic grade amplifier.

Be in view of amplifying circuit it is highly sensitive, the design of Electromagnetic Shielding of metal shielding box also determine reduce as far as possible it is outer Boundary's interference.Further, the design of high-accuracy power supply is the influence for reducing power network fluctuation and interference to signal acquisition.

Optical path is more effectively collected using optical fiber.Metal shielding box has aperture to introduce optical fiber, enables light energy More concentrate and can be more flexible to the design of optical path.

The emergent light face of optical fiber is fixed on the concavees lens on the inside of metal shielding box, then converges on photocell, Ke Yigeng The convergence light energy of concentration improves the purity and bandwidth of light so as to use narrower slit in optical path early period.

The photocell is nested on the pedestal of polytetrafluoroethylene material production, is then welded on circuit module 3；Photoelectricity Pond is more sensitive to temperature, by the isolation of pedestal, is on the one hand to give photocell one stable Supporting Media, plays simultaneously Heat-insulated and heat preservation effect.

The photronic window is provided with concavees lens, changes the position of monochromatic light convergent point by adjusting nut, into one Step convergence optical path enhances energy, and closes photronic photosurface, avoids the influence of stray light and air-flow.

The high impedance line surrounded from photronic pin to input is set, and feedback resistance and feedback capacity are connected to high impedance Node, the protective layer extended around these passive elements, protective layer are to apply copper form.

Entire circuit system is enclosed in metal shielding box with the electromagnetic interference outside reduction, also reduces air-flow and temperature On photronic influence.

In conclusion the utility model keeps compact using photodiode, cost is lower than photomultiplier tube, sensitive Degree is high and will be also superior to the characteristic of photomultiplier tube in terms of anti-interference.And further in circuit design, using high-precision Power supply be that the low-pass filtered module of the linear Voltage stabilizing module of rectification filtering module through high-precision linear voltage-stablizer makees circuit mode It connects and to obtain more preferably performance, femto-ampere grade amplifier is used to constitute symmetric circuit design etc. for core；Using band optical fiber and thoroughly The light guidance mode of mirror assembly, and all sensing units are arranged in metal shielding box and are surrounded with deposited copper form from photoelectricity The pin in pond is to improve sensitivity to technical measures such as the high impedance transmission lines of input, and high anti-interference ability is made contributions.

Claims (6)

1. a kind of highly sensitive high jamproof photodiode detector, which is characterized in that setting packet in metal shielding box (1) It includes circuit module (3), photocell (11) and photoelectricity stall (10), optical fiber (4) and fibre-optical splice (5), lens (6) and lens mount (8), adjusting nut (7), heat preservation isolation (2) and output terminal (9).

2. a kind of highly sensitive high jamproof photodiode detector as described in claim 1, which is characterized in that described Circuit module (3) includes high-precision power supply (31) that two-stage amplifying circuit (32) is connected with circuit mode.

3. a kind of highly sensitive high jamproof photodiode detector as claimed in claim 2, which is characterized in that described High-precision power supply (31) is the low-pass filtered module of the linear Voltage stabilizing module of rectification filtering module through high-precision linear voltage-stablizer Make circuit mode connection；

The two-stage amplifying circuit (32) includes that the trans-impedance amplifier of first order measurement photodiode and the second level are buffered The voltage follower of isolation connects composition, using full symmetric structure.

4. a kind of highly sensitive high jamproof photodiode detector as claimed in claim 3, which is characterized in that described Trans-impedance amplifier is the ADA4530-1 of TIA；The voltage follower is made of OP27.

5. a kind of highly sensitive high jamproof photodiode detector as described in claim 1, which is characterized in that described Photocell is nested on the pedestal of polytetrafluoroethylene material production, is welded on circuit module (3)；

Optical path incorporation way is that the monochromatic light after monochromator light splitting imports simultaneously face concavees lens front end by optical fiber, by adjusting spiral shell Mother changes the position of monochromatic light convergent point, and photocell is placed in concavees lens rear end near focal point.

6. a kind of highly sensitive high jamproof photodiode detector as described in claim 1, which is characterized in that setting It surrounds high impedance line, feedback resistance and feedback capacity from photronic pin to input and is connected to high-impedance node, along nothing The protective layer extended around source element, the protective layer are to apply copper form.