Time measuring device, fluorescence lifetime measuring device and time measuring method

Abstract

The time measurement device (10) of the present invention comprises: a TAC circuit (12); a measuring gate (11) which is arranged between a detector (4) and the TAC circuit (12) and is set to a first state in which a detection signal passes in the direction of the TAC circuit (12) or a second state in which the detection signal does not pass in the direction of the TAC circuit (12); a control unit (14) which functions as a setting unit for setting the time when the measuring gate (11) is set to the second state, i.e., the gate dead time, to the measuring gate (11); and a control unit (14) which functions as a deriving unit for deriving and outputting time information related to the detection signal based on the measurement signal output from the TAC circuit (12), wherein the control unit (14) functions as a setting unit and sets a time which is an integer multiple of the repetition period of the fluorescence detected in the detector 4, i.e., a time which is longer than the dead time of the TAC circuit (12) itself, as the gate dead time to the measuring gate (11).

Description

Technical Field

[0001] One embodiment of the present invention relates to a time measurement device, a fluorescence lifetime measurement device, and a time measurement method. Background Art

[0002] A time-correlated single photon counting (TCSPC) device for measuring fluorescence lifetime is known (for example, see Patent Document 1). The TCSPC device described in Patent Document 1 has a plurality of TDC (time-digital-converter) circuits. The TDC circuit outputs the time measurement result as a digital signal.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: German Patent Application Publication No. 102008004549 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In the above-mentioned TDC circuit and TAC (Time-Analog-Converter) circuit that outputs the time measurement result as an analog signal, if the time is measured, a certain period of time after the measurement becomes a dead time in which the time measurement cannot be performed again. Due to the dead time, when a phenomenon such as fluorescence is detected and time measurement related to the phenomenon is performed (for example, fluorescence lifetime measurement), it may not be possible to properly obtain the time waveform related to the phenomenon. In other words, the time waveform cannot be obtained during the dead time, so even if the obtainable time waveform is synthesized, the correct time waveform related to the phenomenon cannot be obtained.

[0008] One embodiment of the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a time measurement device, a fluorescence lifetime measurement device, and a time measurement method that can appropriately acquire a time waveform related to a phenomenon.

[0009] Technical solutions to solve problems

[0010] A time measuring device in one embodiment of the present invention comprises: a first time measuring device, which inputs a detection signal output by a detector when detecting a phenomenon, and outputs a measurement signal corresponding to the time related to the detection signal; a gate portion, which is arranged between the detector and the first time measuring device and is set to a first state in which the detection signal passes in the direction of the first time measuring device, or a second state in which the detection signal does not pass in the direction of the first time measuring device; a setting portion, which sets a gate dead time in the gate portion, and the gate dead time is the time when the gate portion is set to the second state; and an exporting portion, which exports and outputs time information related to the detection signal based on the measurement signal output from the first time measuring device, and the setting portion sets a time that is an integer multiple of the repetition period of the phenomenon detected in the detector, that is, a time longer than the dead time of the first time measuring device itself, as the gate dead time in the gate portion.

[0011] In a time measurement device in one embodiment of the present invention, a first state in which a detection signal is input to a first time measurement device that outputs a measurement signal corresponding to a time associated with a detection signal and a second state in which the detection signal is not input are switched. A gate portion is set with a gate dead time that is an integer multiple of a repetition cycle of a phenomenon, that is, longer than a dead time of the first time measurement device itself, and the second state is set during the gate dead time. In such a time measurement device, since the gate dead time that is an integer multiple of the repetition cycle of the phenomenon is set for the gate portion, a time waveform based on time information derived from a measurement signal output from the first time measurement device becomes a waveform that is temporally continuous before and after the dead time (non-measurement state). Furthermore, in the present time measurement device, since the gate dead time set in the gate portion is longer than the dead time of the first time measurement device itself, even in the measurement state in which the detection signal is input to the first time measurement device, the situation in the dead time of the first time measurement device itself is unlikely to occur, and the continuity of the time waveform before and after the gate dead time can be appropriately ensured. As described above, according to the time measurement device of one embodiment of the present invention, it is possible to appropriately (continuously) acquire a time waveform related to a phenomenon.

[0012] Alternatively, the time measurement device further includes a delay generation circuit, the setting unit sets a delay amount that is an integer multiple of the repetition period in the delay generation circuit, the delay generation circuit receives an input of a detection signal that has passed through the gate unit set to the first state, and outputs a delayed signal delayed by the delay amount set by the setting unit to the detection signal to the gate unit, the gate unit is set to the second state until receiving an input of the delay signal after being set to the first state and passing the detection signal, and is set to the first state until receiving an input of a new detection signal after receiving an input of the delay signal. According to this structure, a gate dead time that is an integer multiple of the repetition period can be reliably set to the gate unit.

[0013] Alternatively, the first time measuring device may include: a time-to-amplitude converter that outputs a measurement signal corresponding to the time associated with the detection signal as an analog signal; and a converter that converts the analog signal output from the time-to-amplitude converter into a digital signal and outputs the digital signal. By using the time-to-amplitude converter that outputs the measurement signal as an analog signal and the converter, the time resolution of the measurement of the phenomenon can be improved compared to the case of using, for example, a time-to-digital converter.

[0014] Alternatively, the time measurement device further comprises: a counter that outputs a count signal according to a clock signal, a first time measurement device that inputs a detection signal and a clock signal and outputs a measurement signal corresponding to the time between the detection signal and the clock signal, and a derivation unit that derives and outputs time information based on the count signal output from the counter and the measurement signal output from the first time measurement device. According to this structure, the counter that operates synchronously with the frequency signal outputs a count signal to perform a rough time measurement (low time resolution and long time measurement) that depends on the frequency of the clock, and the first time-to-amplitude converter outputs a measurement signal corresponding to the time between the detection signal and the clock signal to perform a fine time measurement (high time resolution and short time measurement) that compensates for the measurement roughness of the counter. By combining these time measurement results to derive the final time information, high time resolution and long time measurement can be achieved.

[0015] A fluorescence lifetime measurement device according to one embodiment of the present invention is a fluorescence lifetime measurement device for measuring the lifetime of fluorescence emitted from a measurement object, and comprises: a light source that generates light; a detector that detects fluorescence from the measurement object irradiated with light from the light source and outputs a detection signal; the above-mentioned time measurement device that outputs time information related to the detection signal; and a calculation unit that derives the fluorescence lifetime of the measurement object based on the time information. According to this fluorescence lifetime measurement device, the time waveform of the fluorescence lifetime can be appropriately (continuously) obtained using the above-mentioned time measurement device. In order to obtain the time waveform of the fluorescence lifetime, complex light amount adjustment and delay adjustment are currently required, but according to the fluorescence lifetime measurement device of the present invention, such complex adjustments are not required, and the time waveform of the fluorescence waveform can be easily obtained.

[0016] Alternatively, the fluorescence lifetime measurement device may further include: a signal generating unit that generates a pulse signal for controlling the light output of the light source, and the signal generating unit outputs a setting signal that is synchronized with the pulse signal and indicates the repetition period of the fluorescence to the setting unit. Thus, by outputting the setting signal that is synchronized with the pulse signal and indicates the repetition period of the fluorescence from the signal generating unit that generates the pulse signal, the gate dead time that is an integer multiple of the repetition period of the fluorescence can be appropriately set in the gate unit in the setting unit.

[0017] Alternatively, the calculation unit may output a setting signal indicating the fluorescence repetition period to the setting unit. Thus, by outputting the setting signal indicating the fluorescence repetition period from the calculation unit, the setting unit may appropriately set a gate dead time that is an integer multiple of the fluorescence repetition period to the gate unit.

[0018] Alternatively, the fluorescence lifetime measurement device may further include: a signal generation unit that generates a pulse signal for controlling the light output of the light source, the signal generation unit outputs a synchronization signal synchronized with the pulse signal, the time measurement device may further include: a second time measurement device that outputs a signal corresponding to the synchronization signal, and the derivation unit may derive time information based on the signal corresponding to the synchronization signal. In this way, the actual time when the fluorescence is generated can be taken into account and the fluorescence lifetime can be derived with higher accuracy.

[0019] A time measurement method in one embodiment of the present invention is a time measurement method performed by a time measurement device, comprising: a process of setting the first dead time, during which a detection signal output by a detector when detecting a phenomenon is not input into the time measurement device, to an integer multiple of a repetition period of the phenomenon; and a process of deriving and outputting time information related to the detection signal based on the detection signal output from the time measurement device, wherein the first dead time is longer than the second dead time of the time measurement device itself.

[0020] Effects of the Invention

[0021] According to one aspect of the present invention, a time waveform related to a phenomenon can be appropriately acquired. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 FIG. 1 is a diagram schematically showing a fluorescence lifetime measurement device according to the present embodiment.

[0023] Figure 2 This is a diagram for explaining the time measurement principle of the TAC circuit.

[0024] Figure 3 This is a diagram for explaining the time measurement principle of the TAC circuit.

[0025] Figure 4 This is a diagram for explaining the time measurement principle of the TAC circuit.

[0026] Figure 5 It is a diagram for explaining how to obtain a time waveform.

[0027] Figure 6 It is a diagram for explaining how to obtain a time waveform.

[0028] Figure 7 It is a diagram for explaining how to obtain a time waveform.

[0029] Figure 8 It is a diagram for explaining how to obtain a time waveform.

[0030] Fig. 9 It is a diagram for explaining how to obtain a time waveform.

[0031] Fig.10 It is a diagram for explaining how to obtain a time waveform.

[0032] Fig.11 It is a diagram for explaining how to obtain a time waveform.

[0033] Fig.12 It is a diagram for explaining how to obtain a time waveform.

[0034] Fig.13 It is a diagram for explaining how to obtain a time waveform in a comparative example.

[0035] Fig.14 It is a diagram for explaining how to obtain a time waveform in a comparative example.

[0036] Fig.15 It is a diagram for explaining how to obtain a time waveform in a comparative example.

[0037] Fig.16 It is a diagram for explaining how to obtain a time waveform in a comparative example.

[0038] Fig.17 It is a diagram for explaining how to obtain a time waveform in a comparative example.

[0039] Fig.18 It is a diagram for explaining how to obtain a time waveform in a comparative example.

[0040] Fig.19 FIG. 1 is a diagram schematically showing a fluorescence lifetime measurement device according to a modified example.

[0041] Fig. 20 FIG. 1 is a diagram schematically showing a fluorescence lifetime measurement device according to a modified example.

[0042] Fig.21 FIG. 1 is a diagram schematically showing a fluorescence lifetime measurement device according to a modified example.

[0043] Fig. 22 FIG. 1 is a diagram schematically showing a fluorescence lifetime measurement device according to a modified example. DETAILED DESCRIPTION

[0044] Hereinafter, embodiments of a time measurement device, a time measurement method, and a fluorescence lifetime measurement device according to one embodiment of the present invention will be described in detail with reference to the drawings.

[0045] Figure 1 2 is a diagram schematically showing a fluorescence lifetime measurement apparatus 1 according to the present embodiment. The fluorescence lifetime measurement apparatus 1 is an apparatus for measuring the lifetime of fluorescence emitted from a sample S (measurement object).

[0046] The fluorescence spectrum of an organic material or a fluorescent probe is an important parameter for controlling and evaluating the functions or characteristics of a sample, such as the peak wavelength or fluorescence intensity. However, since the information of the fluorescence spectrum is obtained by integrating the fluorescence spectrum by time, when the sample contains multiple substances or reaction systems, only the integrated information can be obtained. In this case, as a method for evaluating the functions or characteristics of the sample, it is effective to measure the fluorescence lifetime in the sub-nanosecond to millisecond time region after the sample is photoexcited by pulsed light until it returns to the ground state. In the fluorescence lifetime measurement device 1 of the present embodiment, the detection timing of the fluorescence is derived by the time measurement device 10 described later, and the frequency distribution of the detection timing is obtained by detecting the fluorescence multiple times, and the fluorescence lifetime of the sample S is estimated based on the frequency distribution.

[0047] like Figure 1 As shown, the fluorescence lifetime measurement device 1 is composed of: a pulse generator 2 (signal generating unit), a light source 3, a detector 4, a computer (calculation unit) 5, a display device 6, an input device 7, and a time measurement device 10. Figure 1 In the structure of the fluorescence lifetime measurement device 1, a clock generation circuit 9 (see Figure 2 ) icon.

[0048] The pulse generator 2 generates a pulse signal for controlling the output of light from the light source 3, and outputs the pulse signal to the light source 3. The pulse generator 2 generates the pulse signal based on an instruction from the computer 5. More specifically, the pulse generator 2 receives a setting signal indicating a repetition period of fluorescence from the computer 5, and generates the pulse signal according to the setting signal.

[0049] The light source 3 outputs the excitation light irradiated to the sample S based on the pulse signal outputted from the pulse generator 2. That is, the light source 3 irradiates the sample S with light. As the light source 3, an LED (Light Emitting Diode) light source, a laser source, an SLD (Super Luminescent Diode) light source, a lamp-based light source, etc. can be used. The intensity of the excitation light can also be set to the following degree, that is, when the excitation light is irradiated to the sample S, one photon is emitted. Fluorescence corresponding to the excitation light is output from the sample S irradiated with the excitation light.

[0050] The detector 4 detects the fluorescence from the sample S irradiated with the light from the light source 3, and outputs the detection signal to the measurement gate 11 (details will be described later) of the time measurement device 10. As the detector 4, a photomultiplier tube, an avalanche photodiode, an HPD (Hybrid Photo Detector), an SSPD (Superconductive Single Photon Detector), etc. can be used.

[0051] The computer 5 derives the fluorescence lifetime based on the measurement result output from the time measurement device 10 (more specifically, the control unit 14). Specifically, the computer 5 derives the frequency distribution of the fluorescence detection time based on the fluorescence time information (fluorescence detection time) included in the measurement result, and obtains the fluorescence lifetime of the sample S based on the frequency distribution. In addition, the computer 5 outputs a setting signal indicating the repetition period of fluorescence to the pulse generator 2 and the control unit 14. The computer 5 is composed of, for example, a computing unit such as a CPU and a storage unit such as a RAM or a flash memory. In addition, the computer 5 can also assume the function of the control unit 14 of the time measurement device 10.

[0052] The display device 6 is a display electrically connected to the computer 5, and displays the fluorescence lifetime analysis results of the sample S. The input device 7 is a keyboard or a mouse, and can input and set the fluorescence lifetime analysis conditions or measurement conditions.

[0053] The time measurement device 10 is a time measurement device that calculates the time from the input of the first trigger signal to the input of the second trigger signal as the measured time. The time measurement device 10 can be applied to various devices and systems that derive the difference in the input time of two signals (the first trigger signal and the second trigger signal) input at different times. In this embodiment, as described above, the time measurement device 10 is applied to the fluorescence lifetime measurement device 1 that measures the lifetime of fluorescence emitted from the sample S.

[0054] like Figure 1 As shown, the time measurement device 10 includes: a measurement gate 11 (first switching unit), a TAC (Time-Analog-Converter) circuit 12 (time amplitude converter) constituting a first time measurement device, a TAC control unit 13, a control unit 14 (setting unit, derivation unit), and a delay generation circuit 30. Figure 1 In the structure of the time measuring device 10, the digital counter 20 described later is omitted (see Figure 2 The digital counter 20 may be provided in the TAC control unit 13 or may be provided separately from the TAC control unit 13.

[0055] The TAC circuit 12 is a circuit of a time-to-amplitude converter that outputs the time difference from the input of the first trigger signal to the input of the second trigger signal as an analog signal (amplitude). The TAC circuit 12 is configured to be able to measure a time of 10 ns, for example. Specifically, the TAC circuit 12 uses the detection signal output by the detector 4 when detecting fluorescence (phenomenon) as the first trigger signal, and outputs the detection signal from the clock generation circuit 9 (see Figure 2 ) as the second trigger signal, and outputs an analog signal (amplitude) corresponding to the time between the detection signal and the clock signal as a measurement signal to the TAC control unit 13. That is, the TAC circuit 12 inputs the detection signal and the clock signal output by the detector 4 when detecting fluorescence, and outputs a measurement signal corresponding to the time between the detection signal and the clock signal (time related to the detection signal). The TAC circuit 12 receives the input of the detection signal via the measurement gate 11.

[0056] The TAC control unit 13 is an AD converter that converts the analog signal (amplitude) outputted from the TAC circuit 12 into a digital signal and outputs the digital signal. The TAC control unit 13 outputs the digital signal after the AD conversion to the control unit 14 as a measurement signal.

[0057] The measuring gate 11 receives the input of the first trigger signal, i.e., the detection signal, from the detector 4, and outputs the detection signal to the TAC circuit 12. The measuring gate 11 is provided between the detector 4 and the TAC circuit 12, and is set to a first state in which the detection signal passes in the direction of the TAC circuit 12, or a second state in which the detection signal does not pass in the direction of the TAC circuit 12. That is, the measuring gate 11 is always set to one of the first state and the second state. A dead time (gate dead time) is set in the measuring gate 11. The dead time (gate dead time) here refers to the time when the measuring gate 11 is set to a state in which the detection signal does not pass in the direction of the TAC circuit 12, i.e., the time of the above-mentioned second state. The gate dead time is set by the control unit 14 (setting unit) via the delay generating circuit 30, and is set to a time that is an integer multiple of the repetition period of the phenomenon (e.g., the fluorescence detected in the detector 4). In addition, the gate dead time set by the control unit 14 is set to a time that is longer than the dead time of the TAC circuit 12 itself. The dead time of the TAC circuit 12 itself refers to a time during which the TAC circuit 12 cannot measure time again for a certain period of time after measuring time.

[0058] Specifically, the measuring gate 11 receives a delay signal from the delay generating circuit 30, and switches between the first state and the second state based on the delay signal. That is, after the measuring gate 11 is set to the first state and the detection signal passes through, it is set to the second state until the delay signal is input, and after the delay signal is input, it is set to the first state until a new detection signal is input. The delay signal is set to a signal delayed by a delay amount that is an integer multiple of the repetition period of the fluorescence (details will be described later). Therefore, in the measuring gate 11, by setting the second state after the detection signal passes through until the delay signal is input, the gate dead time set to the second state can be appropriately set to an integer multiple of the repetition period of the fluorescence.

[0059] The control unit 14 functions as a setting unit that sets the gate dead time, which is the time when the measuring gate 11 is set to the second state, to the measuring gate 11 and as a deriving unit that derives and outputs time information related to the detection signal based on the measurement signal output from the TAC control unit 13 .

[0060] The control unit 14, as a setting unit, sets a time that is an integer multiple of the repetition period of the fluorescence detected in the detector 4, that is, a time that is longer than the dead time of the TAC circuit 12 itself, as a gate dead time in the measuring gate 11. The control unit 14 sets the gate dead time in the measuring gate 11 via the delay generating circuit 30. The control unit 14 performs delay control of the delay generating circuit 30 based on the setting signal (signal indicating the repetition period of the fluorescence) input from the computer 5. That is, the control unit 14 pre-sets a delay amount that is an integer multiple of the repetition period in the delay generating circuit 30 based on the setting signal. The delay generating circuit 30 outputs a delayed signal delayed by the set delay amount to the measuring gate 11. In detail, the delay generation circuit 30 is configured to receive the detection signal that has passed through the measurement gate 11 set to the first state (in the same manner as the TAC circuit 12), and when receiving the input of the detection signal, outputs a signal delayed by the delay amount set by the control unit 14 to the measurement gate 11. As described above, the measurement gate 11 is set to the second state (gate dead time state) after the detection signal has passed until the delay signal is received. Therefore, the gate dead time of the measurement gate 11 can be set to an integral multiple of the repetition period of the fluorescence.

[0061] The control unit 14, as a function of a deriving unit, generates a signal based on the digital counter 20 (see Figure 2 ) and the measurement signal output from the TAC circuit 12 and converted into a digital signal in the TAC control unit 13, and the time information related to the detection signal detected by the detector 4 is derived and output. Figure 2As shown, the digital counter 20 is a counter to which the detection signal from the detector 4 and the clock signal from the clock generation circuit 9 are input. The digital counter 20 operates in synchronization with the clock signal, and outputs a count signal to the control unit 14 according to the clock signal (counts the clock signal). Although such a digital counter 20 can measure the detection signal for a long time, it is difficult to improve the time resolution. The control unit 14 combines the time measurement result of the digital counter 20 with the time measurement result of the TAC circuit 12 with high time resolution, thereby realizing high time resolution and long-term measurement of time information related to the detection signal.

[0062] Figure 3 and Figure 4 : is a diagram illustrating the derivation of the above-mentioned time information. Figure 3 and Figure 4 In the example, the horizontal axis represents the time axis. Figure 3 As shown, the digital counter 20 counts the clock signal and outputs a counting signal. Figure 3 : An example in which the digital counter 20 outputs count signals representing 23, 24, 25, 26, 27, and 28 is shown. As described above, the digital counter 20 operates in synchronization with the clock signal. Figure 3 As shown, currently, the TAC circuit 12 measures the time difference T from the input of the detection signal TRG1 from the detector 4 to the input of the next clock signal TRG2 of the detection signal TRG1. In the measurement signal output by the TAC circuit 12, as shown in FIG. Figure 4 As shown, from the moment when the detection signal TRG1 is input (time t1), the voltage (amplitude) starts to increase corresponding to the detection signal TRG1, and from the moment when the clock signal TRG2 is input (time t2), the voltage (amplitude) is constant corresponding to the clock signal TRG2.

[0063] The control unit 14 derives time information indicating the time until the detection signal is input to the TAC circuit 12 by subtracting the time indicated by the measurement signal from the time corresponding to the count value indicated by the count signal. Figure 3 In the example shown, the control unit 14 derives time information (23-T) indicating the time until the detection signal TRG1 is input to the TAC circuit 12 by subtracting the time difference T, which is the time information indicated by the measurement signal, from the time 23 corresponding to the count value indicated by the count signal. The derivation of such time information is achieved by matching the clock signal of the input digital counter 20 with the clock signal of the input TAC circuit 12 (the count value indicated by the clock signal of the input TAC circuit 12 is uniquely determined). The control unit 14 outputs the derived time information (measurement result) to the computer 5.

[0064] Next, refer to Figures 5 to 18, the significance (effect) of setting the gate dead time to an integer multiple of the fluorescence repetition period is explained. Figure 5 to Figure 12 It is a diagram for explaining acquisition of a fluorescence time waveform in the fluorescence lifetime measurement apparatus 1 according to the present embodiment. Figure 13 to Figure 18 FIG. 1 is a diagram for explaining how to obtain a fluorescence time waveform in the fluorescence lifetime measurement device 1 of the comparative example. Figures 5 to 18 , the horizontal axis represents time.

[0065] Currently, considering Figure 5 The above paragraph shows the case of repeated fluorescence incidence. Figure 5 In the example shown, the frequency of the pulse signal output from the pulse generator 2 is 1 MHz, and the repetition period of the fluorescence is 1 μs. Figure 5 The curve shown in the upper part of the figure produces fluorescent light. Figure 5 The multiple quadrilaterals shown in the upper part of the figure represent the generation of photons related to fluorescence (hereinafter, Figure 6 The same is true for the following figures). Figure 5 In the lower part of FIG. 4 , the detection signal output from the detector 4 is shown. By the generation of photons, such as Figure 5 As shown in the lower part of , at the timing of detecting each photon, a detection signal corresponding to each photon is output from the detector 4.

[0066] Here, in the TAC circuit 12, after a photon is input (after the time is measured), a dead time occurs in which time measurement cannot be performed again for a certain period of time. In a conventional fluorescence lifetime measurement device (for example, the fluorescence lifetime measurement device of the comparative example described later), in order to minimize the omission of photon counting, the dead time of the device is shortened as much as possible, and no dead time other than the dead time of the TAC circuit 12 itself is set. In this regard, in the fluorescence lifetime measurement device 1 of the present embodiment, a time that is an integer multiple of the repetition period of fluorescence (and longer than the dead time of the TAC circuit 12 itself) is set as the gate dead time in the measuring gate 11. Figure 6 The lower part of FIG. 1 shows an example in which a gate dead time of 1 times the repetition period of fluorescence (the same as the repetition period of fluorescence) is set in the measurement gate 11. In addition, Figures 6 to 10 The “dead time” in the figure refers to the gate dead time.

[0067] If after measuring the initial photon Figure 6 The gate dead time (initial gate dead time) shown in FIG. 1 is not able to obtain the signal in the initial gate dead time. Therefore, the initial gate dead time is actually measured by measuring the detection signal of the gate 11. Figure 7 Then, when the initial gate dead time ends and the next photon is measured, Figure 8The gate dead time (the second gate dead time) shown in FIG. 1 is a gate dead time. Since the signal during the second gate dead time cannot be obtained, if the second gate dead time is taken into account, the detection signal of the measuring gate 11 is actually as follows: Fig. 9 As shown in the lower part of FIG. 1 , if the gate dead time is repeated after the photon is measured, the detection signal of the measuring gate 11 is actually as follows: Fig.10 shown.

[0068] Here, the time that can be measured in this fluorescence lifetime measurement device (the time that can be measured when photons are generated) is Fig.11 The time shown in the "measurement area" of the fluorescence lifetime measurement device 1 is a measurement standby state in which measurement can be performed as long as photons are input. The measurement standby state is the time when the fluorescence lifetime measurement device 1 actually performs time measurement. Fig.12 As shown in FIG. 1 , it can be seen that if the "measurement areas" are arranged in the order of generation on the time axis, the original fluorescence emission curve is displayed. The reason is that if the gate dead time is set to an integer multiple of the fluorescence repetition period (here 1), the time waveforms before and after each dead time are synthesized, and a waveform that is continuous in time and equivalent to the waveform of the fluorescence curve is obtained. As described above, by setting the dead time of an integer multiple of the fluorescence repetition period to the measurement gate 11, it is possible to achieve measurement as if continuous measurement is performed (continuous acquisition of fluorescence waveforms).

[0069] Next, for a structure without setting the gate dead time (structure of a comparative example), refer to Figure 13 to Figure 18 In addition, Figure 13 to Figure 16 The "dead time" in the above description refers to the dead time of the TAC circuit itself rather than the gate dead time. Fig.13 As shown in the upper part of the figure, the repetition period of fluorescence is set to 1μs, and the gate dead time is not set. Since the gate dead time is not set, Fig.13 As shown in the lower part of the figure, the dead time after the photon is detected is only the dead time of the TAC circuit itself (a dead time shorter than the gate dead time mentioned above). Fig.13 Then, at the end of the initial dead time, as Fig.14 As shown in the lower part of the figure, a photon can be measured, and a dead time is generated again after the measurement of the photon. When the second dead time ends, as shown in the figure Fig.15 As shown in the lower part of the figure, photons can be measured, and dead time is generated again after the measurement of the photons. In this way, if the gate dead time is repeated after the measurement of photons, the detection signal of the measuring gate is actually as follows Fig.16 And, if Fig.17 The "measurement areas" shown are arranged in the order of generation on the time axis, becoming Fig.18 The waveform shown is the same as the above Fig.12 The waveform shown is different and does not completely match the waveform of the original fluorescence curve. Thus, in a configuration where a dead time that is an integral multiple of the fluorescence repetition period is not set, it is impossible to perform continuous measurement (continuous acquisition of fluorescence waveforms).

[0070] Next, the effects of the time measurement device 10 and the fluorescence lifetime measurement device 1 according to the present embodiment will be described.

[0071] The time measurement device 10 of the present embodiment comprises: a TAC circuit 12, which inputs a detection signal output by a detector 4 when detecting a phenomenon, and outputs a measurement signal corresponding to the time related to the detection signal; a measuring gate 11, which is arranged between the detector 4 and the TAC circuit 12 and is set to a first state in which the detection signal passes in the direction of the TAC circuit 12, or a second state in which the detection signal does not pass in the direction of the TAC circuit 12; a control unit 14, which functions as a setting unit that sets the time when the measuring gate 11 is set to the second state, that is, the gate dead time, to the measuring gate 11; and the control unit 14, which functions as a deriving unit that derives and outputs time information related to the detection signal based on the measurement signal output from the TAC circuit 12. The control unit 14, which functions as a setting unit, sets a time that is an integer multiple of the repetition period of the fluorescence detected in the detector 4, that is, a time longer than the dead time of the TAC circuit 12 itself, as the gate dead time to the measuring gate 11.

[0072] In the time measurement device 10 of the present embodiment, a switch is made between a first state in which the detection signal is input to the TAC circuit 12 that outputs the measurement signal corresponding to the time associated with the detection signal, and a second state in which the detection signal is not input. The measuring gate 11 is set with a gate dead time that is an integer multiple of the repetition period of fluorescence, that is, longer than the dead time of the TAC circuit 12 itself, and becomes the above-mentioned second state during the gate dead time. In such a time measurement device 10, since the gate dead time that is an integer multiple of the repetition period of fluorescence is set for the measuring gate 11, the time waveform of the time information derived from the measurement signal output from the TAC circuit 12 becomes a waveform that is equal to a waveform that is continuous in time before and after the dead time (non-measurement state). Furthermore, in the present time measurement device 10, since the gate dead time set in the measurement gate 11 is longer than the dead time of the TAC circuit 12 itself, even in the measurement state where the detection signal is input to the TAC circuit 12, the situation in the dead time of the TAC circuit 12 itself is unlikely to occur, and the continuity of the time waveform before and after the gate dead time can be appropriately ensured. As described above, according to the time measurement device 10 of this embodiment, the time waveform related to the phenomenon can be appropriately (continuously) obtained.

[0073] Alternatively, the time measurement device 10 further includes a delay generation circuit 30, the control unit 14 functioning as a setting unit sets a delay amount of an integer multiple of the repetition period in the delay generation circuit 30, the delay generation circuit 30 receives an input of a detection signal that has passed through the measurement gate 11 set to the first state, and outputs a delayed signal delayed by the delay amount set by the control unit 14 functioning as a setting unit to the measurement gate 11, the measurement gate 11 is set to the second state until receiving input of the delay signal after being set to the first state and passing the detection signal, and is set to the first state until a new detection signal is input after receiving input of the delay signal. According to this structure, the gate dead time of an integer multiple of the repetition period can be reliably set to the measurement gate 11.

[0074] Alternatively, the first time measuring device may include: a TAC circuit 12 that outputs a measurement signal corresponding to the time associated with the detection signal as an analog signal; and a TAC control unit 13 that converts the analog signal output from the TAC circuit 12 into a digital signal and outputs the digital signal. By using the TAC circuit 12 that outputs the measurement signal as an analog signal and the TAC control unit 13, the time resolution of the measurement of the phenomenon can be improved compared to the case of using, for example, a time-to-digital converter.

[0075] Alternatively, the time measurement device 10 further includes: a digital counter 20 that outputs a count signal based on a clock signal; a TAC circuit 12 that inputs a detection signal and a clock signal and outputs a measurement signal corresponding to the time between the detection signal and the clock signal; and a control unit 14 that functions as a derivation unit derives and outputs time information based on the count signal output from the digital counter 20 and the measurement signal output from the TAC circuit 12. According to this structure, the digital counter 20 that operates synchronously with the clock signal outputs a count signal to perform a rough time measurement (low time resolution and long time measurement) that depends on the frequency of the clock, and the TAC circuit 12 outputs a measurement signal corresponding to the time between the detection signal and the clock signal to perform a fine time measurement (high time resolution and short time measurement) that compensates for the measurement roughness of the digital counter 20. By combining these time measurement results to derive the final time information, high time resolution and long time measurement can be achieved.

[0076] The fluorescence lifetime measurement device 1 of the present embodiment is a fluorescence lifetime measurement device for measuring the lifetime of fluorescence emitted from a sample S, and includes: a light source 3 for irradiating the sample S with light; a detector 4 for detecting the fluorescence from the sample S irradiated with the light from the light source 3 and outputting a detection signal; the above-mentioned time measurement device 10 for outputting time information related to the detection signal; and a computer 5 for deriving the fluorescence lifetime of the sample S based on the time information. According to this fluorescence lifetime measurement device 1, the time waveform of the fluorescence lifetime can be appropriately (continuously) acquired using the above-mentioned time measurement device 10.

[0077] Alternatively, the computer 5 may output a setting signal indicating the fluorescence repetition period to the control unit 14 functioning as a setting unit. In this way, by outputting the setting signal indicating the fluorescence repetition period from the computer 5, the control unit 14 functioning as a setting unit may appropriately set a gate dead time that is an integral multiple of the fluorescence repetition period to the measuring gate 11.

[0078] An embodiment of the present invention has been described above, but the present invention is not limited to the above embodiment. Fig.19As shown in FIG. 1 , the time measurement device 10A of the fluorescence lifetime measurement device 1A may further include a TAC circuit 16. The TAC circuit 16 is a circuit of a time-to-amplitude converter that outputs the time difference from the input of the first trigger signal to the input of the second trigger signal as an analog signal (amplitude). The TAC circuit 16 outputs a signal corresponding to the synchronization signal of the phenomenon related to the detection signal detected by the detector 4. The phenomenon related to the detection signal detected by the detector 4 is the fluorescence from the sample S detected by the detector 4. The synchronization signal of the phenomenon is a signal output by the pulse generator 2 that is synchronized with (for example, the same as) the pulse signal. Specifically, the TAC circuit 16 uses the synchronization signal as the first trigger signal and the clock signal output from the clock generation circuit 9 as the second trigger signal, and outputs an analog signal (amplitude) corresponding to the time difference between the synchronization signal and the clock signal as a signal corresponding to the synchronization signal to the TAC control unit 13. In this case, the control unit 14 functioning as a derivation unit may further consider (based on) the signal corresponding to the synchronization signal output from the TAC circuit 16 and the synchronization signal to derive the time information. That is, the control unit 14 can also determine the start time (starting point) of the phenomenon based on the signal corresponding to the synchronization signal and more accurately derive time information related to the detection signal detected by the detector 4. This can take into account the actual time when fluorescence is generated and derive the fluorescence lifetime with higher accuracy.

[0079] In addition, if Fig. 20As shown, the time measurement device 10B of the fluorescence lifetime measurement device 1B may also have two TAC circuits 16a and 16b as the TAC circuit 16, and further include a reference gate 15. In addition, the time measurement device 10B may also have two TAC control units 13a and 13b as the TAC control unit 13. The TAC circuit 16a outputs a signal corresponding to the above-mentioned synchronization signal to the TAC control unit 13b. In addition, the TAC circuit 16b outputs a signal corresponding to the above-mentioned synchronization signal to the TAC control unit 13b. The TAC control unit 13b converts the signal input from the TAC circuits 16a and 16b into a digital signal and outputs it to the control unit 14. In addition, in this case, the signal output from the TAC circuit 12 may be output to the TAC control unit 13a, and the TAC control unit 13a may convert the signal input from the TAC circuit 12 into a digital signal and output it to the control unit 14. The reference gate 15 switches the TAC circuits 16a and 16b to which the above-mentioned synchronization signal is input, taking into account the dead time of the TAC circuit 16. The reference gate 15 receives an input of a synchronization signal from the pulse generator 2, and outputs the synchronization signal to only one of the TAC circuits 16a and 16b. The reference gate 15 switches the TAC circuits 16a and 16b to which the synchronization signal is input based on switching information that is preset in consideration of the dead time. The switching information is specified in such a way that the synchronization signal is not input to the TAC circuits 16a and 16b during the dead time. In this way, by switching the TAC circuits 16a and 16b to which the synchronization signal is input by the reference gate 15, it is possible to appropriately avoid the deterioration of the signal measurement efficiency due to the influence of the dead time of the TAC circuit 16.

[0080] In addition, if Fig.21 As shown, as in the fluorescence lifetime measurement device 1C having the time measurement device 10C, the pulse generator 2 may output a setting signal indicating the fluorescence repetition period in synchronization with the pulse signal to the control unit 14 functioning as a setting unit. In this way, by outputting the setting signal indicating the fluorescence repetition period in synchronization with the pulse signal from the pulse generator 2 that generates the pulse signal, the control unit 14 functioning as the setting unit can appropriately set the gate dead time that is an integral multiple of the fluorescence repetition period to the measurement gate 11.

[0081] In addition, if Fig. 22 As shown, the time measuring device 10D of the fluorescence lifetime measuring device 1D may include a TAC circuit 16 in addition to the structure of the above-mentioned time measuring device 10C. According to this structure, even in the structure where the setting signal is output from the pulse generator 2, the actual time when fluorescence is generated can be considered and the fluorescence lifetime can be derived with higher accuracy.

[0082] [Explanation of symbols]

[0083] 1, 1A, 1B, 1C, 1D…fluorescence lifetime measuring device, 2…pulse generator (signal generating unit), 3…light source, 4…detector, 5…computer (calculating unit), 10, 10A, 10B, 10C, 10D…time measuring device, 11…measuring gate, 12…TAC circuit (time amplitude converter), 13…TAC control unit (converter), 14…control unit (setting unit, derivation unit), 15…reference gate, 16…TAC circuit (second time measuring device), 20…digital counter, 30…delay generating circuit.

Claims

1. A time measuring device, comprising: A first time measuring device, which receives as input a detection signal output by a detector when the detector detects a phenomenon, and outputs a measurement signal corresponding to a time associated with the detection signal; a gate portion disposed between the detector and the first time measuring device, and set to a first state for allowing the detection signal to pass toward the first time measuring device, or a second state for not allowing the detection signal to pass toward the first time measuring device; a setting unit configured to set a gate dead time in the gate unit, wherein the gate dead time is a time during which the gate unit is set to the second state; and a deriving unit that derives and outputs time information related to the detection signal based on the measurement signal output from the first time measuring device, The setting unit sets, in the gate unit, a time which is an integral multiple of a repetition period of the phenomenon detected by the detector and which is longer than a dead time of the first time measuring device itself as the gate dead time.

2. The time measuring device according to claim 1, wherein: It also has a delay generation circuit. The setting unit sets a delay amount that is an integer multiple of the repetition period in the delay generation circuit, The delay generating circuit receives the input of the detection signal that has passed through the gate section set to the first state, and outputs a delay signal delayed by the delay amount set by the setting section for the detection signal to the gate section. The gate portion is set to the second state until receiving input of the delay signal after being set to the first state and passing the detection signal, and is set to the first state until the detection signal is newly input after receiving input of the delay signal.

3. The time measuring device according to claim 1 or 2, wherein: The first time measuring device includes: a time-to-amplitude converter that outputs the measurement signal corresponding to the time associated with the detection signal as an analog signal; and a converter that converts the analog signal output from the time-to-amplitude converter into a digital signal and outputs the digital signal.

4. The time measuring device according to any one of claims 1 to 3, wherein: The device further comprises: a counter that outputs a count signal according to the clock signal; The first time measuring device receives the detection signal and the clock signal as input, and outputs the measurement signal corresponding to the time between the detection signal and the clock signal. The deriving unit derives and outputs the time information based on the count signal output from the counter and the measurement signal output from the first time measuring device.

5. A fluorescence lifetime measurement device, wherein: This is a fluorescence lifetime measurement device that measures the lifetime of fluorescence emitted from a measurement object. have: a light source, which generates light; the detector detecting the fluorescence from the object to be measured irradiated with the light from the light source and outputting the detection signal; The time measurement device according to any one of claims 1 to 4, which outputs time information related to the detection signal; and A calculation unit is configured to derive a fluorescence lifetime of the object to be measured based on the time information.

6. The fluorescence lifetime measurement device according to claim 5, wherein: The device further comprises: a signal generating unit which generates a pulse signal for controlling the light output of the light source; The signal generating section outputs a setting signal indicating a repetition period of the fluorescence in synchronization with the pulse signal to the setting section.

7. The fluorescence lifetime measurement device according to claim 5 or 6, wherein: The calculation unit outputs a setting signal indicating a repetition period of the fluorescence to the setting unit.

8. The fluorescence lifetime measurement device according to any one of claims 5 to 7, wherein: The device further comprises: a signal generating unit which generates a pulse signal for controlling the light output of the light source; The signal generating unit outputs a synchronization signal synchronized with the pulse signal. The time measurement device further comprises: a second time measurement device that outputs a signal corresponding to the synchronization signal, The deriving unit derives the time information based on a signal corresponding to the synchronization signal.

9. A method for measuring time, wherein: is the time measurement method performed by the time measurement device, Include: A step of setting a first dead time during which a detection signal outputted by a detector detecting a phenomenon is not inputted into a time measuring device to an integral multiple of a repetition period of the phenomenon; and a step of deriving and outputting time information related to the detection signal based on the detection signal output from the time measuring device, The first dead time is longer than a second dead time of the time measuring device itself.

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