CN101309370A - Photoelectric conversion simulating device of TDI CCD apparatus and method thereof - Google Patents

Abstract

The invention provides a photoelectric conversion simulator and a method for a TDI CCD device, which belong to the photoelectric conversion testing device and the method of the TDI CCD. The photoelectric conversion simulator includes a photoelectric conversion module, a buffer-amplifier module, an A/D converter, a digital signal processing circuit, a D/A converter and an output-amplifier module; the photoelectric conversion module is used for finishing receiving the optical signal and the conversion function which is from the optical signal to the electric signal; the buffer-amplifier has the effect of amplifying the signal amplitude properly; the A/D converter is used for finishing the function of digitalizing the analog electric signal; the digital signal processing circuit is responsible for processing the algorithm conversion; the D/A converter is used for converting the numerical value of the TDI CCD output signal to the practical TDI CCD video level; the buffering output-amplifier is used to enhance the capability for driving the back-end circuit. The output signal of the photoelectric conversion simulator is connected with the TDI CCD waveform synthesis generation circuit to integrally simulate and convert the photoelectric performance and electric performance of the TDI CCD so that the TDI CCD device during the circuit debugging stage is avoided from being damaged.

Description

A kind of opto-electronic conversion analogue means and method of TDI CCD device

Technical field

The present invention relates to a kind of TDI CCD is the opto-electronic conversion analogue means and the method for integration time-delay charge coupled device, belongs to opto-electronic conversion testing equipment and method.

Background technology

TDI CCD has this outstanding feature of acquisition high sensitivity under the situation that can not sacrifice spatial resolution and operating rate, and it is with a wide range of applications in high speed, low-light field.In scientific research mission, demand for performance and index, often need to customize novel TDI CCD device, this just needs certain lead time and delivery cycle, sometimes even reach one to two year, this can have a strong impact on the progress of research and production task, and in addition, the cost of TDI CCD device is often very high, complex process, the driving of some novel TDI CCD device requires very complicated, often adopts multiple power supply to power together, and the power-on and power-off of power supply order will satisfy certain priority pass, in case do not meet the demands, perhaps protect bad words and cause components from being damaged easily, cause tremendous loss, this debug phase at circuit can often take place.At present, the waveform generator that industry has begun to design various TDI CCD still all is in the stage of simulation of electrical performance to solve the problem of test substitute, can't realize the complete debugging of optics and electricity system.The output signal of this device is connected to synthetic generation of TDI CCD waveform can carries out the complete simulation of photoelectric properties and electrical property to TDI CCD behind the circuit.

Summary of the invention

The technical problem to be solved in the present invention provides a kind of analogue means that can realize the TDI CCD device of TDICCD device photoelectric translation function in the simulation of the debug phase of equipment development process neutralizing circuit, the video level signal of simulation output TDI CCD.

For solving the problems of the technologies described above, the analogue means of TDI CCD device of the present invention such as accompanying drawing 1 comprise photoelectric conversion module, buffering amplification module, A/D converter, digital signal processing circuit, D/A converter, output amplification module; Photoelectric conversion module is used for finishing receiving optical signals and finishes the translation function of light signal to the signal of telecommunication; Buffering is amplified the suitably effect of amplification of amplitude of finishing signal; A/D converter is used for finishing with the digitized function of analog electrical signal; Digital signal processing circuit is responsible for carrying out algorithm conversion, will represent the numerical quantities after opto-electronic conversion and the digitlization to be converted into the numerical quantities of representing actual TDI ccd output signal; D/A converter is used for the numerical quantities of TDICCD output signal is converted into actual TDI CCD video level; The output buffering is amplified the ability that is used for strengthening driving late-class circuit.

The annexation of each several part is: photoelectric conversion module output analog signal is connected to the buffering amplification module of subordinate, and this signal is connected to A/D converter after amplifying by the buffering amplification module; The digital signal of the output of A/D converter is connected to the digital signal processing circuit input, and the word signal processing circuit output is connected to the D/A converter input; D/A converter output analog signal is connected to output amplification module input; Export amplification module at last and export actual TDI CCD video level.

Photoelectric conversion module structure wherein is as follows:

The effect of this circuit is that external optical signals is converted into the signal of telecommunication.Circuit theory diagrams such as accompanying drawing 2.The element of realizing opto-electronic conversion adopts photodiode.Reason is that the photoelectric characteristic of photodiode is a linear relationship, and is comparatively approaching with the photoelectric characteristic of CCD, only needs to get final product through linear transformation when the photoelectric characteristic of simulation CCD.After photodiode is accepted illumination, produce photogenerated current.This electric current carries out forming voltage after the current/voltage conversion through resistance.This voltage signal is exported to late-class circuit after buffering is amplified.

Described buffering amplification module:

Finish the signal that higher level's circuit is converted and carry out the amplification of voltage magnitude, strengthen coupling ability with late-class circuit.

Described A/D converter:

The effect of this modular circuit is that the signal of telecommunication of reaction light signal power that photoelectric conversion module is obtained carries out digitlization.Data after the digitlization are input to late-class circuit by output data bus.

Described digital signal processing circuit:

The function of this circuit is to realize being converted to through fixing algorithm by the numerical value of the light conditions that reflects photodiode the digital quantity of reflection TDICCD output voltage values.Algorithm wherein is as follows.

Adopt linear corresponding method.The photoelectric respone of photodiode such as accompanying drawing 2.Photodiode photoelectric respone illumination and photogenerated current under certain reversed bias voltage is linear.After being converted to voltage, resistance is equivalent to illumination and the resistance both end voltage is linear.This point is consistent with the photobehavior of CCD.Therefore relational expression is as follows under the situation of having ignored dark current separately:

V _CCD＝T _diR _eE _e ①

V wherein _CCD: be the output voltage of photogenerated charge after amplifying on the sheet of CCD device.

T _Di: be the integration progression of CCD device.

R _e: be the luminous sensitivity (one-level integration progression) of CCD device.

E _e: be the image planes irradiation.

$V_{\mathrm{diode}}=\frac{E_e}{T_{\mathrm{int}}}{\mathrm{KRA}}_0$ ②

V wherein _Diode: be the output voltage of photoelectric conversion module.

E _e: the same.

T _Int: the image planes time for exposure.

K: the irradiance of photodiode-photogenerated current response curve slope.

R: photoelectric conversion module output resistance.

A ₀: the gain that buffering is amplified.

The K slope can be taken up an official post by the response curve of photodiode and be got any and obtain.

Can get VCCD, V by (1), (2) formula _DiodeCorresponding relation is as follows:

$V_{\mathrm{CCD}}=\frac{T_{\mathrm{di}}{R}_e{T}_{\mathrm{int}}}{{\mathrm{KRA}}_0}{\mathrm{<figure-callout\; id="3"\; label="V\; diode"\; filenames="A20081005094400101.png"\; state="\{\{state\}\}">V</figure-callout>}}_{\mathrm{diode}}$ ③

(3) formula of employing can be converted into the output voltage of photoelectric conversion module the voltage output value of TDI CCD.

Described D/A converter:

The function of D/A converter is that the data transaction with the parallel representative TDI CCD of digital signal processing circuit output becomes analog signal.This signal is output after buffering is amplified.Actual TDI ccd signal as shown in Figure 3.The vision signal of TDI CCD output is different with the common video signal, and every row is made up of a lot of pixel signals.As shown in Figure 4, each effective TDI CCD pixel vision signal is the process from the A level signal to the C level signal, and wherein the spike of a-signal level representative is the interference that is produced by reset signal RST, is called spike, is useless signal, but eliminates not fall.The B signal level is the reset reference level, and the C signal level is the signal level that is triggered by drive signal CR.The useful vision signal that this signal level obtains after relevant processing of circuit is the pressure reduction that is produced by B signal level and C signal level.This pressure reduction is represented the size of the light signal that TDI CCD chip gathers at this pixel place and strong and weak.And the amplitude size after buffering is amplified output equals the size of this pressure reduction.Utilize this signal to cooperate follow-up ccd signal combiner circuit can realize the simulation of the opto-electronic conversion performance of TDI CCD.

Described output buffering amplification module:

Since the present invention can simulating TDI CCD device photoelectric converting function, therefore, in lead time of optoelectronic device and debug process, can replace TDI CCD device simulation opto-electronic conversion with its part; Or be used with TDI CCD electrical property signal generator, thereby finish the simulation of TDI CCD device photoelectric and complete performance simulation, not only shorten the lead time of equipment, and avoided the generation of circuit debugging stage TDI CCD device failure phenomenon.

Description of drawings

Fig. 1 is a structured flowchart of the present invention.

Fig. 2 is the photoelectric conversion module circuit theory diagrams.

Fig. 3 is the illumination response curve of photodiode.

Fig. 4 is the schematic diagram of buffer amplifier circuit.

Fig. 5 is a TDI CCD pixel signal.

Fig. 6 is the algorithm flow that carries out electric first conversion among the DSP.

Fig. 7 is to use the physical structure schematic diagram of photodiode simulating TDI CCD.

Embodiment

Below in conjunction with the drawings and specific embodiments the present invention is described in further detail.

Embodiment 1

The IT-F6-2048B type TDI ccd image sensor of selecting for use Canadian DALSA company to produce is an example, introduces the basic structure of TDI CCD.The pixel structure 2048 * 96 of this TDI CCD.It is 96 grades TDICCD for two-way, the optional output of single channel two-way, progression.Photosensitive unit is N * M arrangement architecture in the TDI CCD photosensitive area, and N is a horizontal direction pixel number, and M is the pixel number (being 96 pixels) of vertical direction.The not only online column direction of TDICCD but also exist shift clock to drive in TDI progression direction could guarantee that like this signal charge bag is transferred to detecting unit in an orderly manner.

Now the TEMD5010 with VISHAY company is an example, introduces the basic principle of photodiode.TEMD5010 is a kind of high speed, highly sensitive PIN type photodiode.Its sensitive volume is the spectral region of 400nm-1000nm.TEMD5010 can be applied in infrared ray sensor, in the high speed visual light imaging equipment.

IT-F6-2048B type TDI CCD with DALSA company is a simulated target, is the specific implementation method of example explanation TDI CCD device pixel analogue means with TEMD5010.

The pixel analogue means of TDI CCD device of the present invention comprises photoelectric conversion module 1 as shown in Figure 1, buffering amplification module 2, A/D converter 3, digital signal processing circuit 4, D/A converter 5, output amplification module 6.

As shown in Figure 2, diode adopts TEMD5010 in the realization circuit of photoelectric conversion module.The photoelectric respone curve of TEMD5010 such as accompanying drawing 3.The resistance R resistance adopts 50k Ω.Power supply adopts direct current 15V power supply (ignoring the variation of the photoelectric respone degree that the bias variations of photodiode brings).

As shown in Figure 1, buffer amplifier circuit adopts integrated transporting discharging AD812 formation in-phase amplifier to cushion.Circuit theory diagrams such as accompanying drawing 4.Wherein Shu Ru signal is the voltage of photoelectric switching circuit output.So this circuit gain A ₀Be 1.

As shown in Figure 1, A/D change-over circuit and digital signal processing circuit adopt the TMS320LF2407 chip of TI company to realize.TMS320LF2407 is special digital signal processing CPU.Its peripheral integrated important peripheral hardware such as ADC, SCI, SPI.The realization of A/D modular converter of the present invention can utilize TMS320LF2407 to go up integrated ADC equipment.Digital signal processor is connected with the internal bus that the connection of A/D modular converter also is converted into TMS320LF2407.The processor of TMS320LF2407 obtains the data volume that ADC transforms by inner ADC register.

The major parameter relevant with opto-electronic conversion of TDI CCD IT-F6-2048B is as follows: sensitivity (96TDI) 1920V/ μ J/cm ²If image planes time for exposure T _InT is 1s.Can get TEMD5010 by accompanying drawing 3 again is 1mW/cm at the image planes irradiance ²The time photogenerated current be 63 μ A

Therefore can get

K＝63 ④

Unit Wherein μ A is a current unit, cm ²Square measure, the mW power unit.Bring top known conditions into formula (3) and can get following formula:

$V_{\mathrm{CCD}}=\frac{1920\&times;1}{63\&times;{10}^{-6}\&times;1000\&times;50\&times;{10}^3}{V}_{\text{diode}}$

V _CCD＝0.6·V _diode ⑤

Thereby can calculate the corresponding right output level size of TDI CCD of photoelectric conversion module output according to (5) formula.Formula above service routine is finished in DSP calculates.Program circuit such as accompanying drawing 6.

As shown in Figure 1, the DA change-over circuit adopts D/A converter 3 to adopt ten high-speed d/a transducer AD9750.Its effect is that the tens word conversion of signals that DSP produces is become corresponding analog signal.For example when the output area of D/A be 0～1V, 1111111111 of output is changed into 1V and 0000000000 is changed into 0V.The level of D/A converter 3 outputs passes through the level size after output amplifier 5 is amplified to corresponding reflection TDI CCD opto-electronic conversion again.

As shown in Figure 1, output buffer can adopt the form of buffering amplification module.

Embodiment 2

On the principle basis of embodiment 1, several can be simulated the pixel unit cell arrangement as shown in Figure 7 and become delegation, constitute the analog machine of line array CCD device.Calculated relationship is as follows: be of a size of L in linear array sensitization, when photodiode length is M, can use N photodiode to be used for the photoelectric characteristic of simulating TDI CCD.Wherein N uses following formula:

$N=\frac{L}{M}$ ⑥

Now the IL-P1 molded lines array image sensor of producing with Canadian DALSA company is an example, and this series has the different models of the quick unit of 4096,2048,1024,512 pictures.Each is 10 μ m * 10 μ m as quick cell size, and existing is example with 4096 devices as quick unit, and the L in the formula (6) is 40.96mm.

Now the TEMD5010 with VISHAY company is the basic structure that example is introduced photodiode.TEMD5010 is a kind of high speed, highly sensitive PIN type photodiode.Its sensitive volume is the spectral region of 400nm-1000nm.TEMD5010 can be applied in infrared ray sensor, in the high speed visual light imaging equipment.Its overall dimension is 5mm * 5mm.M in the formula (6) is 5mm.

Thus, the N of formula in 6. is 8.Therefore 8 TEMD5010 are arranged in delegation, and with the aliging of CCD device as quick unit original position, finish the simulation of IL-P1 4096 devices.Visible light-sensitive diode 1 can be measured 1 to 512 sensitization situation on the CCD device, and photodiode 2 can be measured 513 to 1024 sensitization situations on the CCD device, and the like can utilize the quick unit of picture on this device dividual simulation CCD device.

Claims (4)

1, a kind of opto-electronic conversion analogue means of TDI CCD device, it is characterized in that this device comprises photoelectric conversion module (1), buffering amplification module (2), A/D converter (3), digital signal processing circuit (4), D/A converter (5), output amplification module (6);

Photoelectric conversion module (1) is used for receiving optical signals and finish the conversion of light signal to the signal of telecommunication, buffering amplification module (2) amplifies the amplitude of signal, A/D converter (3) is with the analog electrical signal digitlization, digital signal processing circuit (4) is responsible for carrying out the algorithm conversion, and D/A converter (5) is converted into actual TDI CCD video level with the numerical quantities of TDI ccd output signal; Output amplification module (6) is used for strengthening driving the driving force of late-class circuit;

The output signal of this device is connected in the synthetic generation of the TDI CCD waveform circuit, the annexation of each several part is: photoelectric conversion module (1) output analog signal is connected to the buffering amplification module (2) of subordinate, this signal is connected to A/D converter (3) after amplifying by buffering amplification module (2); The digital signal of the output of A/D converter (3) is connected to digital signal processing circuit (4) input, and word signal processing circuit (4) output is connected to D/A converter (5) input; D/A converter (5) output analog signal is connected to output amplification module (6) input; Export the actual TDI CCD video level of amplification module (6) output at last.

2, the opto-electronic conversion analogue means of TDI CCD device according to claim 1, it is characterized in that photo-electric conversion element adopts photodiode in the described digital signal processing circuit (4), after photodiode is accepted illumination, produce photogenerated current, this electric current carries out forming voltage after the current/voltage conversion through resistance, and this voltage signal is exported to late-class circuit after buffering is amplified.

3, the opto-electronic conversion analogue means and the method for TDI CCD device according to claim 1, it is characterized in that described this digital signal processing circuit (4) is to realize being converted to the digital quantity that reflects the TDICCD output voltage values by the numerical value of the light conditions that reflects photodiode through fixing algorithm, algorithm wherein is as follows:

Photodiode photoelectric respone illumination and photogenerated current under certain reversed bias voltage is linear, be equivalent to illumination and the resistance both end voltage is linear after resistance is converted to voltage, therefore relational expression is as follows under the situation of having ignored dark current separately:

V _CCD＝T _diR _eE _e (1)

V wherein _CCD: be the output voltage of photogenerated charge after amplifying on the sheet of CCD device

T _Di: be the integration progression of CCD device

R _e: be the one-level integration progression luminous sensitivity of CCD device

E _e: be the image planes irradiation

$V_{\mathrm{diode}}=\frac{E_e}{T_{\mathrm{int}}}{\mathrm{KRA}}_0---\left(2\right)$

V wherein _Diode: be the output voltage of photoelectric conversion module

E _e: be the image planes irradiation

T _Int: the image planes time for exposure

K: the irradiance of photodiode-photogenerated current response curve slope

R: photoelectric conversion module output resistance

A ₀: the gain that buffering is amplified

The K slope can be taken up an official post by the response curve of photodiode and be got any and obtain can getting V by (1), (2) formula _CCD, V _DiodeCorresponding relation is as follows:

$V_{\mathrm{CCD}}=\frac{T_{\mathrm{di}}{R}_e{T}_{\mathrm{int}}}{\mathrm{KR}{A}_0}{V}_{\mathrm{diode}}---\left(3\right)$

(3) formula of employing is converted into the output voltage of photoelectric conversion module the voltage output value of TDI CCD.

4, the opto-electronic conversion analogue means opto-electronic conversion method of TDI CCD device according to claim 3 is characterized in that N simulation pixel unit cell arrangement become delegation, and its linear array sensitization is of a size of L, and when photodiode length was M, wherein N used following formula:

$N=\frac{L}{M}---\left(6\right)$

With the quick unit of picture on this device dividual simulation CCD device.

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