3D Time-of-flight distance measurement with custom - Universität ...

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DEMODULATION PIXELS IN CMOS/CCD 117 quantities quantum efficiency, conversion capacitance and amplification can be measured directly or independently from each other in the present implementation. Since we never know the exact process parameters, we can only roughly estimate amplification and conversion capacitance with an accuracy of about ± 10%: Conversion capacitance: Cc = 40 fF Amplification of SF stage: ASF = 0.9 Quantum efficiency at 630nm: 65% � Sensitivity: � Responsivity: q S = ASF =3.6 µV/electron Cc q R( λ ) = QE( λ) ⋅ S = QE( λ) ⋅ ASF ⋅ =2.35 µV/photon @ 630 nm Cc With the measurement conditions listed in MCD02 in the appendix we measure an output voltage swing of 3.60 V. The theoretical calculations (all parameters in MCD02) predict a swing of 3.25 V, which agrees very well with the measurement (within the expected uncertainty range of ± 10%). Saturation of output stage and CCD gates The maximum signal (charge) that can be handled by a CCD structure is limited by two independent (saturation) mechanisms. Firstly the charge must not exceed the CCD gate’s charge handling capability and secondly the output voltage swing caused by the signal charge must be within the operation range of the output amplifier. The charge handling capability is essentially influenced by the voltage difference between the single CCD gates (Qmax=Cgate⋅∆Vmax). A high voltage difference allows more charge carriers to be integrated than a low voltage difference. It is the purpose of this section to investigate the voltage difference between the integration gate and the modulated photogate that defines a charge handling capability just leading to saturation of the output stage. In general, we expect the demodulation contrast to increase with high voltage amplitudes on the modulated photogates. It is obvious, however, that for a certain modulation amplitude, depending on the actual voltage of the integration gate IG and the amount of
118 CHAPTER 5 charge already integrated, it will be possible for charge carriers integrated under IG to be transported back into the light sensitive pixel area and to be dumped to the dump diffusion. The maximum charge to be integrated within the pixel is defined by the output stage. The conversion capacitance of 40 fF, together with the amplification of 0.9 and a maximum output voltage swing of 4 V, leads to a maximum number of about 1,100,000 electrons that can be integrated without causing signal clipping due to saturation of the output stage. To determine the charge that leads to saturation of the output stage, we bias the gates PGM and PGR with 10 V (so that they are definitely at a higher potential than PGL) and use PGL as a variable barrier. In this way the potential difference between PGL and IG adjusts the amount of charge that IG can hold (c.f. Figure 5.9). The integration gate IG is always biased at 10.7 V, a reliable amplitude that avoids device damage by oxide break through. The illumination time is chosen to be long enough that the potential well, generated by the potential difference between IG and PGL, is always totally filled. Additionally generated charge carriers can no longer be held by IG. As the result of this measurement we find that a potential-difference of 2.2 V between IG and PGL defines the full-well charge that leads to saturation of the output stage (IG=10.7 V, PGL=8.5 V). For lower PGL voltages (e.g. 8 V) the output signal does not increase further, because the amount of charge that will be integrated then leads to saturation of the output stage. For higher PGL voltages (e.g. 9 V), the output signal decreases, because the full-well charge is smaller than the maximum charge that the output stage can handle. Therefore, the amplitude of PGL should not exceed 8.5 V for the demodulation application (assuming IG = 10.7 V). Otherwise, the maximum signal that can be handled is no longer limited by the output stage but by the actual potential difference between IG and PGL.
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3D Time-of-flight distance measurem
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To my parents
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Meinen Eltern
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II 4. Power budget and resolution l
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Abstract Since we are living in a t
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centimeter accuracy. With the singl
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X Eine elegantere Methode zur Entfe
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INTRODUCTION 1 1. Introduction One
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INTRODUCTION 3 light source observe
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INTRODUCTION 5 Propagation time, ho
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INTRODUCTION 7 Chapter 3 gives a sh
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OPTICAL TOF RANGE MEASUREMENT 9 2.
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OPTICAL TOF RANGE MEASUREMENT 13 pr
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OPTICAL TOF RANGE MEASUREMENT 15 hi
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OPTICAL TOF RANGE MEASUREMENT 17 Pu
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OPTICAL TOF RANGE MEASUREMENT 19 Ad
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OPTICAL TOF RANGE MEASUREMENT 21 pr
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OPTICAL TOF RANGE MEASUREMENT 23 wh
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OPTICAL TOF RANGE MEASUREMENT 25 δ
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OPTICAL TOF RANGE MEASUREMENT 27 c(
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OPTICAL TOF RANGE MEASUREMENT 29 A
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OPTICAL TOF RANGE MEASUREMENT 31 ph
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OPTICAL TOF RANGE MEASUREMENT 33 Ts
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OPTICAL TOF RANGE MEASUREMENT 35 f1
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OPTICAL TOF RANGE MEASUREMENT 37 an
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OPTICAL TOF RANGE MEASUREMENT 39 in
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OPTICAL TOF RANGE MEASUREMENT 41 Ss
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OPTICAL TOF RANGE MEASUREMENT 43 Fr
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OPTICAL TOF RANGE MEASUREMENT 45 1
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50 CHAPTER 3 the smearing effect, r
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52 CHAPTER 3 3.1 Silicon properties
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54 CHAPTER 3 (a) Figure 3.3 Optical
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56 CHAPTER 3 Quantum efficiency in
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58 CHAPTER 3 The different operatio
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60 CHAPTER 3 (a) (b) Depletion widt
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62 CHAPTER 3 Very special processes
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64 CHAPTER 3 1 kT Dn = ⋅ vth ⋅
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Page 87 and 88: 70 CHAPTER 3 Flicker noise is cause
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Page 91 and 92: 74 CHAPTER 3 amount of the charge p
Page 93 and 94: 76 CHAPTER 3 substrate (Equation 3.
Page 95 and 96: 78 CHAPTER 3 charge carriers the CT
Page 97 and 98: 80 CHAPTER 3 without causing short
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Page 103 and 104: 86 CHAPTER 4 Figure 4.1 P lens Lamb
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Page 111 and 112: 94 CHAPTER 4 Cmod = 1 QE(λ) = 0.65
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IMAGING TOF RANGE CAMERAS 167 Delay
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IMAGING TOF RANGE CAMERAS 169 6.3 3
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IMAGING TOF RANGE CAMERAS 171 Gate
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IMAGING TOF RANGE CAMERAS 173 Bound
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IMAGING TOF RANGE CAMERAS 175 Figur
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IMAGING TOF RANGE CAMERAS 177 Final
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IMAGING TOF RANGE CAMERAS 179 #5 #6
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SUMMARY AND PERSPECTIVE 181 7. Summ
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SUMMARY AND PERSPECTIVE 183 into th
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SUMMARY AND PERSPECTIVE 185 or phas
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188 CHAPTER 8 8.2 Typical parameter
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190 CHAPTER 8 Spectral luminous int
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192 CHAPTER 8 MCD03S: Conditions SC
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194 CHAPTER 8 MCD06S: Measurement c
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196 [BRK] Brockhaus, “Naturwissen
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198 [KAI] I. Kaisto, et al., “Opt
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200 [SP1] T. Spirig et al., “The
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ACKNOWLEDGMENTS 203 Acknowledgments
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206 Publication list 1. R. Lange, P
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