Optical distance measuring device and laser direct writing exposure machine

Abstract

The invention discloses an optical distance measuring device and a laser direct writing exposure machine, the optical distance measuring device comprises a laser, an optical splitter, a zoom lens group, a short-wave pass filter, a cylindrical mirror group, a detector and a control module, the laser is used for emitting a distance measuring incident beam; the optical splitter is arranged on an emergent light path of the laser; the zoom lens group is arranged on a reflection light path of the optical splitter; the short-wave pass filter is arranged on an emergent light path of the zoom lens group; the cylindrical mirror group is arranged on a transmission light path of the optical splitter and is used for focusing the distance measurement reflection light beam transmitted by the optical splitter; the detector is arranged on the light emitting side of the cylindrical mirror group and is used for outputting a measurement current signal according to the distance measurement reflection light beam; and the control module is connected with the detector and is used for determining the drift distance of the to-be-exposed plane according to the measurement current signal. By adopting the device, the measurement precision of the optical distance measuring device can be effectively improved, and the optical distance measuring device is low in cost, small in optical device number, small in size and suitable for dynamic measurement scenes.

Description

Technical Field

[0001] The present invention relates to the technical field of optical ranging, and in particular to an optical ranging device and a laser direct writing exposure machine. Background Art

[0002] In the prior art, a laser triangulation ranging system is used to measure the offset of the plane to be exposed. However, the short baseline length and the angular change of the laser beam will affect the measurement accuracy of the laser triangulation ranging. Increasing the measurement accuracy will lead to an increase in the cost of the optical ranging device. In addition, the response time of the laser triangulation ranging is relatively long, resulting in poor measurement effects for dynamic application scenarios. Or a WDI (Wavefront Distortion Image, autofocus) ranging system is used to measure the offset of the plane to be exposed. However, the WDI ranging system has a large measurement error, the WDI ranging system is expensive, and the precision optical devices in the WDI ranging system need to be maintained and calibrated regularly, which will additionally increase the operation and maintenance costs of the WDI ranging system. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, an object of the present invention is to provide an optical ranging device. By using this device, the measurement accuracy of the optical ranging device can be effectively improved, and the cost of the optical ranging device is very low, the number of optical devices is small, and the volume is small, which is suitable for dynamic measurement scenarios.

[0004] A second object of the present invention is to provide a laser direct writing exposure machine.

[0005] To solve the above problems, an embodiment of the first aspect of the present invention provides an optical ranging device, including: a laser for emitting a ranging incident beam; a beam splitter disposed on the outgoing light path of the laser for reflecting or transmitting the ranging incident beam; a zoom lens group disposed on the reflected light path of the beam splitter for adjusting the focusing position of the ranging incident beam reflected by the beam splitter; a short-wave pass filter disposed on the outgoing light path of the zoom lens group for reflecting the focused ranging incident beam to the plane to be exposed and receiving the ranging reflected beam reflected by the plane to be exposed based on the ranging incident beam; a cylindrical lens group disposed on the transmitted light path of the beam splitter for focusing the ranging reflected beam transmitted by the beam splitter; a detector disposed on the light output side of the cylindrical lens group for outputting a measurement current signal according to the ranging reflected beam; and a control module connected to the detector for determining the drift amount of the plane to be exposed according to the measurement current signal.

[0006] An optical ranging device according to an embodiment of the present invention is based on the structural settings of a laser, a beam splitter, a zoom lens group, a short-wave pass filter, a cylindrical lens group, and a detector. After the ranging incident beam passes through the beam splitter, the zoom lens group, and the short-wave pass filter and reaches the plane to be exposed, the plane to be exposed reflects the ranging incident beam. The ranging reflected beam is focused on the detector through the cylindrical lens group, and the detector generates a measurement current signal according to the ranging reflected beam. Thus, the drift amount of the plane to be exposed can be detected by measuring the change of the current signal. Therefore, compared with the method of measuring the offset amount of the plane to be exposed by the laser triangulation ranging system and the WDI ranging system in the prior art, the optical ranging device in the present application detects the drift amount of the plane to be exposed through the measurement current signal received by the detector. The optical ranging device can adjust the focal plane of the ranging beam to be consistent with that of the laser beam through the zoom lens group, thereby effectively improving the measurement accuracy of the optical ranging device. Moreover, the cost of the optical ranging device is very low, there are few optical components, and the volume is small, which can be applied to dynamic measurement scenarios.

[0007] In some embodiments, the detector is a quadrant detector, and the quadrant detector is configured to form a ranging light spot according to the ranging reflected beam and generate a measurement current signal corresponding to each quadrant region according to the area change of the ranging light spot in each quadrant region; the control module is specifically configured to process multiple measurement current signals to obtain a light spot change signal and determine the drift amount of the plane to be exposed according to the light spot change signal.

[0008] In some embodiments, the control module includes: a cross-group amplification unit connected to the quadrant detector for amplifying each measurement current signal to output a corresponding measurement voltage signal; a gain unit connected to the cross-group amplification unit for gaining each measurement voltage signal to obtain a gained measurement voltage signal; a logic unit connected to the gain unit for performing a logic operation on each gained measurement voltage signal to obtain the light spot change signal; and a filtering unit connected to the logic unit for filtering the light spot change signal to obtain a filtered light spot change signal.

[0009] In some embodiments, the gain unit includes a plurality of gain subunits, and each gain subunit includes: a power transistor, the gate of the power transistor is connected to the output end of the cross-group amplification unit, and the drain of the power transistor is connected to a preset power supply; an analog multiplexer, the control end of the analog multiplexer is connected to the source of the power transistor, the output end of the analog multiplexer is connected to the logic unit, the ground end of the analog multiplexer and the negative power supply end of the analog multiplexer are grounded, and the positive power supply end of the analog multiplexer is connected to a power supply; a first resistor, the first end of the first resistor is connected to the source of the power transistor and the control end of the analog multiplexer, and the second end of the first resistor is grounded; a second resistor, the first end of the second resistor is connected to the first input end of the analog multiplexer, and the second end of the second resistor is connected to the output end of the cross-group amplification unit; a third resistor, the first end of the third resistor is connected to the second input end of the analog multiplexer, and the second end of the third resistor is connected to the output end of the cross-group amplification unit.

[0010] In some embodiments, the filtering unit includes: a fourth resistor, a first end of the fourth resistor is connected to an output end of the logic unit; a first capacitor, a first end of the first capacitor is connected to the output end of the logic unit and the first end of the fourth resistor; a fifth resistor, a first end of the fifth resistor is connected to a second end of the fourth resistor; a sixth resistor, a first end of the sixth resistor is connected to a second end of the first capacitor; a second capacitor, a first end of the second capacitor is connected to the first end of the sixth resistor and the second end of the first capacitor, and a second end of the second capacitor is connected to a second end of the fifth resistor; a third capacitor, a first end of the third capacitor is connected to the second end of the fourth resistor and the first end of the fifth resistor, and a second end of the third capacitor is connected to a second end of the sixth resistor; an operational amplifier, a first non-inverting input end of the operational amplifier is connected to the second end of the fifth resistor and the second end of the second capacitor, a first inverting input end of the operational amplifier is connected to the second end of the sixth resistor, the second end of the third capacitor, and a first output end of the operational amplifier, a second output end of the operational amplifier is connected to a second inverting input end of the operational amplifier, a third output end of the operational amplifier is connected to a third inverting input end of the operational amplifier to output the filtered spot change signal, and a power supply end of the operational amplifier is connected to a power supply; a variable resistor, a fixed end of the variable resistor is connected to the second output end of the operational amplifier and the second inverting input end of the operational amplifier, an adjustable end of the variable resistor is connected to a second non-inverting input end of the operational amplifier, and a sliding end of the variable resistor is grounded; a terminal block, a first terminal of the terminal block is grounded, and a second terminal of the terminal block is connected to the second output end of the operational amplifier, the second inverting input end of the operational amplifier, and the fixed end of the variable resistor.

[0011] In some embodiments, the measured voltage signals include a first measured voltage signal, a second measured voltage signal, a third measured voltage signal, and a fourth measured voltage signal, where the first measured voltage signal is the signal corresponding to the first quadrant region in the quadrant detector, the second measured voltage signal is the signal corresponding to the second quadrant region in the quadrant detector, the third measured voltage signal is the signal corresponding to the third quadrant region in the quadrant detector, and the fourth measured voltage signal is the signal corresponding to the fourth quadrant region in the quadrant detector; the logic unit includes: a first addition sub-unit, connected to the gain unit, for performing an addition operation on the first measured voltage signal and the third measured voltage signal to obtain a first operation result; a second addition sub-unit, connected to the gain unit, for performing an addition operation on the second measured voltage signal and the fourth measured voltage signal to obtain a second operation result; a third addition sub-unit, connected to the first addition sub-unit and the second addition sub-unit, for performing an addition operation on the first operation result and the second operation result to obtain a third operation result; a subtraction sub-unit, connected to the first addition sub-unit and the second addition sub-unit, for performing a subtraction operation on the first operation result and the second operation result to obtain a fourth operation result; a division sub-unit, connected to the third addition sub-unit, the subtraction sub-unit, and the filtering unit, for obtaining the spot change signal according to the third operation result and the fourth operation result.

[0012] In some embodiments, the division sub-unit includes: a divider, the first input terminal of the divider is connected to the subtraction sub-unit, the second input terminal, the voltage control terminal, and the third input terminal of the divider are commonly connected and then grounded, the fourth input terminal of the divider is connected to the third addition sub-unit; a fourth capacitor, the first end of the fourth capacitor is connected to the negative power supply terminal of the divider and the negative terminal of the power supply, the second end of the fourth capacitor is connected to the fifth input terminal of the divider and then grounded; a fifth capacitor, the first end of the fifth capacitor is grounded, the second end of the fifth capacitor is connected to the positive power supply terminal of the divider and the positive terminal of the power supply; a seventh resistor, the first end of the seventh resistor is connected to the output terminal of the divider, the sixth input terminal of the divider, and the filtering unit, the second end of the seventh resistor is grounded; a sixth capacitor, the first end of the sixth capacitor is connected to the first end of the seventh resistor, the second end of the sixth capacitor is grounded; a seventh capacitor, the first end of the seventh capacitor is connected to the first end of the sixth capacitor, the second end of the seventh capacitor is grounded.

[0013] In some embodiments, the zoom lens group includes: a plano-convex lens located on the outgoing light path of the beam splitter for focusing the ranging incident light beam; a plano-concave lens located on the outgoing light path of the plano-convex lens for diverging the ranging incident light beam; the cylindrical lens group includes: a first cylindrical convex lens disposed on the transmitted light path of the beam splitter for focusing the ranging reflected light beam; and a second cylindrical convex lens disposed on the outgoing light path of the first cylindrical convex lens for further focusing the focused ranging reflected light beam.

[0014] In some embodiments, the optical ranging device further includes: a beam expander disposed on the outgoing light path of the laser and between the beam splitter and the laser for expanding the ranging incident light beam.

[0015] To solve the above problems, an embodiment of the second aspect of the present invention provides a laser direct writing exposure machine, including: the optical ranging device described in the above embodiment; an exposure objective lens disposed on the outgoing light path of the optical ranging device for converging the ranging incident light beam output by the optical ranging device to the plane to be exposed.

[0016] According to the laser direct writing exposure machine of the embodiments of the present invention, the use of the optical ranging device can effectively improve the measurement accuracy of the optical ranging device, and the optical ranging device has low cost, few optical components, and small volume, and is suitable for dynamic measurement scenarios.

[0017] The additional aspects and advantages of the present invention will be partially given in the following description, partially become apparent from the following description, or be understood through the practice of the present invention. Description of the Drawings

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, where: Figure 1 is a schematic diagram of an optical ranging device according to an embodiment of the present invention; FIG. 2(a)-(c) are schematic diagrams of ranging light spots according to an embodiment of the present invention; Figure 3 is a block diagram of a control module according to an embodiment of the present invention; Figure 4 is a schematic circuit diagram of a gain subunit according to an embodiment of the present invention; Figure 5 is a schematic circuit diagram of a filtering unit according to an embodiment of the present invention; Figure 6 is a block diagram of a logic unit according to an embodiment of the present invention; Figure 7 Schematic diagram of signal processing of a control module according to an embodiment of the present invention; Figure 8 Circuit schematic diagram of a subtraction subunit according to an embodiment of the present invention; Figure 9 Circuit schematic diagram of a division subunit according to an embodiment of the present invention; Figure 10 Schematic diagram of a laser direct writing exposure machine according to an embodiment of the present invention.

[0019] Reference numerals: Laser direct writing exposure machine 100; Exposure objective lens 20; Optical ranging device 10; Laser 1; Beam splitter 2; Zoom lens group 3; Short-wave pass filter 4; Cylindrical lens group 5; Detector 6; Control module 7; Beam expander 8; Plano-convex lens 31; Plano-concave lens 32; First cylindrical convex lens 51; Second cylindrical convex lens 52; Meniscus lens 81; Plano-convex lens 82; Cross-group amplification unit 11; Gain unit 12; Logic unit 13; Filter unit 14; Gain subunit 121; First addition subunit 15; Second addition subunit 16; Third addition subunit 17; Subtraction subunit 18; Division subunit 19; Power transistor Q1; First resistor R1; Second resistor R2; Third resistor R3; Fourth resistor R4; Fifth resistor R5; Sixth resistor R6; Seventh resistor R7; Eleventh resistor R11; Twelfth resistor R12; Thirteenth resistor R13; Fourteenth resistor R14; Fifteenth resistor R15; First capacitor C1; Second capacitor C2; Third capacitor C3; Fourth capacitor C4; Fifth capacitor C5; Sixth capacitor C6; Seventh capacitor C7; Wiring terminal P2; Variable resistor RF1; Analog multiplexer 101; Operational amplifier 102; Divider 103; Fixed end CCW; Sliding end CW; Adjustable end WIPER; Ground terminal GND of the analog multiplexer; Negative power supply terminal VSS; Positive power supply terminal VDD; Control terminal A0; First input terminal S1A; Second input terminal S2A of the analog multiplexer; First non-inverting input terminal +IN_A; First inverting input terminal -IN_B; First output terminal OUT_B; Second output terminal OUT_A; Second inverting input terminal -IN_A; Third output terminal OUT_D; Third inverting input terminal -IN_D; Output terminal W; First input terminal X1; Second input terminal X2; Third input terminal Y1; Fourth input terminal Z2; Fifth input terminal Z1; Sixth input terminal Y2; Negative power supply terminal VN; Preset power supply REF; Power supply VCC. Specific embodiments

[0020] The embodiments of the present invention will be described in detail below. The embodiments described with reference to the accompanying drawings are exemplary. The embodiments of the present invention will be described in detail below.

[0021] In a laser direct writing lithography machine, an optical ranging device is required to measure the working distance from the lithography lens to the plane to be exposed, and to monitor at all times whether the plane to be exposed coincides with the focal plane of the lithography lens. Based on the different focal depths of lenses with different magnifications, different requirements are imposed on the measurement range and resolution of the ranging device. Common ranging methods in the prior art include laser triangulation ranging and WDI ranging, but both laser triangulation ranging and WDI ranging have certain limitations.

[0022] Laser triangulation ranging irradiates a plane to be exposed with a laser beam at a certain incident angle. The laser is reflected and scattered on the plane to be exposed, and the reflected laser is converged and imaged by a lens at another angle. The light spot is imaged on a CCD (Charge Coupled Device) sensor. When the plane to be exposed moves along the direction of the laser beam, the light spot on the sensor will move, and the displacement size corresponds to the moving distance of the plane to be exposed, so as to achieve the purpose of ranging. However, the measurement accuracy of triangulation ranging usually depends on the baseline length and the angular change of the laser beam. Among them, the baseline length is the distance between the emitter and the detector. When the plane to be exposed is far from the sensor, the angular change is very small, which will lead to a decrease in measurement accuracy. However, in order to maintain high measurement accuracy when the plane to be exposed is far from the sensor, the baseline length needs to be lengthened, which is unrealistic in some applications. Therefore, the measurement range is limited when using laser triangulation ranging for ranging.

[0023] Secondly, the measurement resolution and measurement distance of a laser triangulation ranging system are usually restricted by each other. To improve the accuracy of long-distance measurement by lengthening the baseline length will cause an increase in the volume of the laser triangulation ranging system. At this time, it is necessary to weigh the key degree of resolution and measurement distance. And when the optical ranging device requires high measurement accuracy and the application scenario space is limited, the baseline length cannot be increased. Therefore, there are limitations in resolution and measurement accuracy when using laser triangulation ranging for ranging. To improve the measurement accuracy and measurement range of triangulation ranging, the optical ranging device needs to use high-precision optical components, mirrors and precision detectors, etc., which will increase the overall cost of the optical ranging device. However, for some application scenarios with limited budgets, laser triangulation ranging is not suitable. The laser triangulation ranging system is very sensitive to the angular change between the laser beam and the plane to be exposed. As the distance between the laser beam and the plane to be exposed increases, the incident angle of the laser beam will significantly affect the measurement accuracy. That is to say, the angular change between the plane to be exposed and the laser triangulation ranging system may cause an increase in measurement error.

[0024] In addition, since the measurement of the laser triangulation ranging system requires the reflection and detection of the laser beam, the system response time is relatively long, especially in high-precision applications. If the object moves at high speed, accurate real-time measurement data may not be obtained, resulting in poor measurement effects of laser triangulation for dynamic application scenarios such as high-speed industrial inspection or motion tracking.

[0025] WDI ranging measures the offset of the plane to be exposed through the interference effect. That is to say, when a laser beam is split into two beams, one beam is reflected back through the plane to be exposed, and the other beam serves as the reference light. The two beams are interfered and superimposed through the phase difference between them. Since there is a direct relationship between the phase difference of the light wave and the optical path (i.e., the distance of the plane to be exposed), by accurately measuring the change of the interference fringes, the distance between the object and the sensor can be obtained. However, WDI ranging is very sensitive to environmental conditions, especially temperature fluctuations. Temperature changes may cause slight changes in the wavelength of the laser beam or changes in the optical path length, thereby affecting the measurement accuracy. At the same time, the change in the refractive index of the air will also affect the propagation speed of the laser beam, resulting in measurement errors. The WDI ranging system involves complex optical components (such as beam splitters, mirrors, lenses, etc.) and precise alignment. If the optical path alignment is inaccurate, the measurement results will have large errors. Calibrating and adjusting these components require high-precision equipment and professional operation skills, and the WDI system has more optical devices, and the overall system is usually bulky and difficult to be applied to miniaturized devices or portable devices.

[0026] The measurement range of the WDI ranging system is relatively limited. Generally speaking, the WDI ranging system is suitable for the measurement of small displacements, usually from the micron level to the millimeter level. When the offset distance of the plane to be exposed is large, the measurement accuracy will decrease significantly. In addition, the WDI ranging system relies on the phase difference of the light wave, but the phase difference will repeat after exceeding one wavelength, resulting in the phenomenon of phase ambiguity. In long-distance measurement, the system requires complex algorithms or additional equipment to eliminate the problem of phase ambiguity.

[0027] To solve the above problems, the first aspect embodiment of the present invention provides an optical ranging device. By using this device, the measurement accuracy of the optical ranging device can be effectively improved, and the cost of the optical ranging device is very low, the number of optical devices is small, the volume is small, and it is suitable for dynamic measurement scenarios.

[0028] Next, refer to Figure 1 to describe the optical ranging device 10 according to the embodiment of the present invention. As Figure 1 shown, the optical ranging device 100 includes a laser 1, a beam splitter 2, a zoom lens group 3, a short-wave pass filter 4, a cylindrical lens group 5, a detector 6, and a control module (not shown in the figure).

[0029] Among them, the laser 1 is used to emit a ranging incident light beam. The laser 1 can be a 635 nm flat-top laser with a collimated beam diameter of 3 mm. The beam splitter 2 is arranged on the outgoing light path of the laser 1 and is used to reflect or transmit the ranging incident light beam. Among them, the beam splitter 2 can be a beam splitter mirror, which is a flat glass with special coating and can split the incident light beam into two different light beams at a specified ratio. The splitting ratio of the beam splitter mirror can be 50R:50T, that is, half of the ranging incident light beam is transmitted and half is reflected at 90°. This splitting ratio can make the best use of the energy of the laser. When the requirement for the beam energy is not high, the splitting ratio can also be 40R:60T, 30R:70T, 20R:80T or 10R:90T, and there is no limit to this. The beam splitter mirror is used to change the incident direction of the ranging incident light beam and the return direction of the ranging reflected light beam. The zoom lens group 3 is arranged on the reflected light path of the beam splitter 2 and is used to adjust the focusing position of the ranging incident light beam reflected by the beam splitter 2. The short-wave pass filter 4 is arranged on the outgoing light path of the zoom lens group 3 and is used to reflect the focused ranging incident light beam to the plane to be exposed and receive the ranging reflected light beam reflected by the plane to be exposed based on the ranging incident light beam. Among them, the short-wave pass filter 4 is a flat glass with special coating. The short-wave pass filter 4 can transmit light with a wavelength band of 400 nm - 530 nm and reflect light with a wavelength band of 575 nm - 725 nm. For example, the wavelength band of the exposure light beam is 405 nm, that is, the short-wave pass filter can transmit the exposure light beam. The cylindrical lens group 5 is arranged on the transmitted light path of the beam splitter 2 and is used to focus the ranging reflected light beam transmitted by the beam splitter 2. The detector 6 is arranged on the light output side of the cylindrical lens group 5 and is used to output a measurement current signal according to the ranging reflected light beam. The control module 7 is connected to the detector 6 and is used to determine the drift amount of the plane to be exposed according to the measurement current signal. The plane to be exposed includes, but is not limited to, mirror surfaces such as wafers and plane mirrors.

[0030] Specifically, the laser 1 emits a ranging incident beam to the beam splitter 2. The beam splitter 2 reflects the ranging incident beam to the zoom lens group 3. The zoom lens group 3 adjusts the ranging incident beam so that the ranging incident beam is exactly focused on the plane to be exposed after being reflected by the short-wave pass filter 4. Based on the principle of reversibility of the optical path, the ranging reflected beam reflected by the plane to be exposed passes through the short-wave pass filter and the zoom lens group 3 in turn and returns to the beam splitter 2. The beam splitter 2 transmits the ranging reflected beam to the cylindrical lens group 5. The cylindrical lens group 5 focuses the ranging reflected beam on the detector 6 so that the detector 6 forms a measurement current signal according to the ranging reflected beam and sends the measurement current signal to the control module. When the plane to be exposed is offset, the angle of incidence of the ranging reflected beam on the cylindrical lens group 5 changes, so that the measurement current signal formed by the detector 6 according to the ranging reflected beam also changes. Thus, the control module can determine the drift amount of the plane to be exposed according to the measurement current signal. The drift amount is the distance between the plane to be exposed and the focal plane position of the exposure beam. For example, the drift amounts corresponding to different measurement current signals are calibrated in the control module, and thus the drift amount of the plane to be exposed can be obtained through the measurement current signal. Therefore, compared with the prior art method of measuring the offset of the plane to be exposed by a laser triangulation ranging system and a WDI ranging system, the optical ranging device 10 in this application detects the drift amount of the plane to be exposed through the measurement current signal received by the detector. The optical ranging device 10 can adjust the ranging beam to be consistent with the focal plane of the laser beam through the zoom lens group 3. Therefore, the transmission of the ranging beam in the optical ranging device 10 is not affected by the refractive index of air, the environment, and the changes in the distance and angle between the plane to be exposed and the laser. This effectively improves the measurement accuracy of the optical ranging device 10. Moreover, when the components in the optical ranging device 10 are not aligned, the position of the detector 6 can be adjusted, further improving the measurement accuracy of the optical ranging device 10. In addition, the cost of the optical ranging device 10 is very low and there are few optical components, so that the volume of the optical ranging device 10 is small. And detecting the distance of the plane to be exposed based on the change of the measurement current signal of the detector 6 enables the optical ranging device 10 to be applicable to dynamic measurement scenarios.

[0031] According to the optical ranging device 10 of the embodiment of the present invention, based on the structural settings of the laser 1, the beam splitter 2, the zoom lens group 3, the short-wave pass filter 4, the cylindrical lens group 5, and the detector 6, after the ranging incident beam passes through the beam splitter 2, the zoom lens group 3, and the short-wave pass filter 4 and reaches the plane to be exposed, the plane to be exposed reflects the ranging incident beam, and the ranging reflected beam is focused on the detector 6 through the cylindrical lens group 5. The detector 6 generates a measurement current signal according to the ranging reflected beam. Thus, the drift amount of the plane to be exposed can be detected by measuring the change of the current signal. Therefore, compared with the method of measuring the offset amount of the plane to be exposed by the laser triangulation ranging system and the WDI ranging system in the prior art, in the optical ranging device 10 of the present application, the drift amount of the plane to be exposed is detected by the measurement current signal received by the detector. The optical ranging device 10 can adjust the focal plane of the ranging beam to be consistent with the focal plane of the laser beam through the zoom lens group 3, thereby effectively improving the measurement accuracy of the optical ranging device 10. Moreover, the cost of the optical ranging device 10 is very low, the number of optical components is small, and the volume is small, which can be applied to dynamic measurement scenarios.

[0032] In some embodiments, the detector 6 is a quadrant photo diode (QPD). The receiving surface of the quadrant photo diode is divided into four quadrant regions. Each quadrant region can output a signal independently when illuminated. The quadrant photo diode is used to form a ranging light spot according to the ranging reflected beam and generate a measurement current signal corresponding to each quadrant region according to the area change of the ranging light spot in each quadrant region. The magnitude of the measurement current signal is proportional to the area size of each quadrant region. The control module 7 is specifically configured to process multiple measurement current signals to obtain a light spot change signal and determine the drift amount of the plane to be exposed according to the light spot change signal. The quadrant photo diode is a quadrant photodiode.

[0033] Wherein, the light spot change signal is the change amount of the area of the test light spot when the plane to be exposed does not shift relative to the area of the test light spot when the plane to be exposed shifts.

[0034] Specifically, when the plane to be exposed is located at the focal plane position of the exposure beam, that is, when the plane to be exposed does not shift, the ranging reflected beam is focused on the surface of the quadrant detector to form a circular ranging spot. The circular spot is shown in Fig. 2(a). At this time, the measured current signal corresponding to each quadrant area of the quadrant detector is zero. The control module 7 processes multiple measured current signals to obtain a spot change signal of zero. When the plane to be exposed shifts, the ranging reflected beam is no longer a collimated beam, and the shape of the ranging spot focused on the quadrant detector will change. At this time, the ranging spot is an elliptical spot, as shown in Figs. 2(b) and 2(c). That is to say, the distribution area of the ranging spot in the four quadrant areas will also change. At this time, the quadrant detector generates the measured current signal corresponding to each quadrant area according to the area change of each quadrant area. The control module 7 processes multiple measured current signals to obtain a spot change signal, and determines the drift amount of the plane to be exposed according to the spot change signal. That is to say, the drift amount of the plane to be exposed corresponding to different spot change signals is pre-calibrated in the control module 7. Thus, the drift amount of the plane to be exposed can be obtained through the spot change signal.

[0035] In the embodiment, the quadrant detector can be a QP1-6 quadrant detector, and this quadrant detector is a 4×0.25 m 2 quadrant detector. That is to say, this quadrant detector is composed of 4 detection units with an area of 0.25 m each. 2 The spectral detection range of the quadrant detector is 400nm - 1100nm, and it is relatively linear in the wavelength band between 632nm and 900nm. The power of the quadrant detector is the largest when the wavelength is 900nm.

[0036] In some embodiments, as Figure 3 shown, the control module 7 includes a cross-group amplification unit 11, a gain unit 12, a logic unit 13, and a filtering unit 14.

[0037] Among them, the cross-group amplification unit 11 is connected to the quadrant detector 6 and is used to amplify each measured current signal to output the corresponding measured voltage signal; the gain unit 12 is connected to the cross-group amplification unit 11 and is used to gain each measured voltage signal to obtain the gain-adjusted measured voltage signal. The gain unit 12 has a gain adjustment function to prevent the measured voltage signal from saturating; the logic unit 13 is connected to the gain unit 12 and is used to perform logical operations on each gain-adjusted measured voltage signal to obtain a spot change signal; the filtering unit 14 is connected to the logic unit 13 and is used to filter the spot change signal to obtain the filtered spot change signal. Thus, the control module 7 determines the drift amount of the plane to be exposed according to the spot change signal.

[0038] In the high-precision optical ranging device 10, in addition to the performance of the quadrant detector itself, the efficiency and stability of photoelectric conversion determine the performance of the entire optical ranging device 10. On the premise of determining the photodiode model of the quadrant detector, designing a high-performance and low-noise control module can improve the response speed and accuracy of the device.

[0039] Specifically, after receiving multiple measurement current signals, the cross-group amplification unit 11 of the control module 7 amplifies each measurement current signal, converts each measurement current signal into a measurement voltage signal, and then sends each measurement voltage signal to the gain unit 12. The gain unit 12 gains each measurement voltage signal to obtain a gain-measured voltage signal for subsequent processing and analysis of the measurement current signal. After receiving the gain-measured voltage signal, the logic unit 13 performs a logical operation on each gain-measured voltage signal to obtain a spot change signal and sends the signal to the filtering unit 14. Since the present application uses the commercial power supply as the power input, there is 50 Hz and its harmonic noise in the output signal, as well as white noise brought by each module itself, which causes large fluctuations in the voltage of the output signal and leads to a decrease in the calculation accuracy of the spot change signal. Therefore, in the present application, the filtering unit 14 is used to filter the spot change signal to obtain a filtered spot change signal, thereby avoiding large fluctuations in the voltage of the spot change signal and improving the accuracy of the spot change signal.

[0040] In some embodiments, the gain unit includes a plurality of gain sub-units 121, such as Figure 4 shown, each gain sub-unit 121 includes a power transistor Q1, an analog multiplexer 101, a first resistor R1, a second resistor R2, and a third resistor R3.

[0041] Among them, the gate of the power transistor Q1 is connected to the output end of the cross-group amplification unit 11, and the drain of the power transistor Q1 is connected to the preset power supply REF, where the preset power supply REF serves as a reference voltage; the control terminal A0 of the analog multiplexer 101 is connected to the source of the power transistor Q1, the output end of the analog multiplexer 101 is connected to the logic unit 13, the ground terminal GND of the analog multiplexer 101 and the negative power supply terminal VSS of the analog multiplexer 101 are grounded, and the positive power supply terminal VDD of the analog multiplexer 101 is connected to the power supply VCC; the first end of the first resistor R1 is connected to the source of the power transistor Q1 and the control terminal A0 of the analog multiplexer 101, and the second end of the first resistor R1 is grounded; the first end of the second resistor R2 is connected to the first input terminal S1A of the analog multiplexer 101, and the second end of the second resistor R2 is connected to the output end of the cross-group amplification unit; the first end of the third resistor R3 is connected to the second input terminal S2A of the analog multiplexer 101, and the second end of the third resistor R3 is connected to the output end of the cross-group amplification unit 11. Thus, each gain sub-unit 121 obtains the measured voltage signal after gain through the power transistor Q1, the analog multiplexer 101, the first resistor R1, the second resistor R2, and the third resistor R3, so as to facilitate the subsequent processing and analysis of the measured current signal. Among them, the power transistor Q1 can be an N-type MOSFET (MOS transistor), and the analog multiplexer 101 can be an ADG409 multiplexing chip. The power transistor Q1, used as a voltage comparator in cooperation with the analog multiplexer 101, can divide multiple gain coefficients, thereby realizing the adaptive gain function. That is to say, the weak current generated by the optical signal irradiating on the quadrant detector is converted into a voltage by the pre-stage cross-group amplifier, compared with the reference voltage, and the high and low levels are output to control the analog multiplexer 101 to open the corresponding channels, that is, to open the first input terminal S1A, the second input terminal S2A, etc. of the analog multiplexer 101, so that the input terminal resistance and the output terminal resistance form different gain coefficients acting on the operational amplifier. Among them, the output terminal resistance can be the second resistor R2 and the third resistor R3, so that the amplification factor can be automatically adjusted according to different power lasers.

[0042] Exemplarily, when the gate of the power transistor Q1 is greater than the drain, the source outputs a high level, and when the gate of the power transistor Q1 is greater than the drain, the source outputs a low level, then the corresponding channels of the first input terminal S1A and the second input terminal S2A of the analog multiplexer 101 are controlled to open, thereby completing the adaptive gain adjustment function.

[0043] In some embodiments, as Figure 5 shown, the filtering unit 14 includes a fourth resistor R4, a first capacitor C1, a fifth resistor R5, a sixth resistor R6, a second capacitor C2, a third capacitor C3, an operational amplifier 102, a variable resistor RF1, and a terminal block P2.

[0044] Among them, the first end of the fourth resistor R4 is connected to the output end of the logic unit 13; the first end of the first capacitor C1 is connected to the output end of the logic unit 13 and the first end of the fourth resistor R4; the first end of the fifth resistor R5 is connected to the second end of the fourth resistor R4; the first end of the sixth resistor R6 is connected to the second end of the first capacitor C1; the first end of the second capacitor C2 is connected to the first end of the sixth resistor R6 and the second end of the first capacitor C1, and the second end of the second capacitor C2 is connected to the second end of the fifth resistor R5; the first end of the third capacitor C3 is connected to the second end of the fourth resistor R4 and the first end of the fifth resistor R5, and the second end of the third capacitor C3 is connected to the second end of the sixth resistor R6; the first non-inverting input terminal +IN-A of the operational amplifier 102 is connected to the second end of the fifth resistor R5 and the second end of the second capacitor C2; the first inverting input terminal -IN_B of the operational amplifier 102 is connected to the second end of the sixth resistor R6, the second end of the third capacitor C3, and the first output terminal OUT_B of the operational amplifier 102; the second output terminal OUT_A of the operational amplifier 102 is connected to the second inverting input terminal -IN_A of the operational amplifier 102; the third output terminal OUT_D of the operational amplifier 102 is connected to the third inverting input terminal -IN_D of the operational amplifier 102 to output the filtered spot change signal; the power supply terminal of the operational amplifier 102 is connected to the power supply, and the power supply terminals are V+ and V-, and the power supply can be 15V; the fixed terminal CCW of the variable resistor RF1 is connected to the second output terminal OUT_A of the operational amplifier 102 and the second inverting input terminal -IN_A of the operational amplifier 102, the adjustable terminal WIPER of the variable resistor RF1 is connected to the second non-inverting input terminal +IN_B of the operational amplifier 102, the sliding terminal CW of the variable resistor RF1 is grounded, and the variable resistor RF1 can adopt 3361P-1-203GLF; the first terminal of the terminal block P2 is grounded, and the second terminal of the terminal block P2 is connected to the second output terminal OUT_A of the operational amplifier 102, the second inverting input terminal -IN_A of the operational amplifier 102, and the fixed terminal CCW of the variable resistor RF1. Thus, the filtering unit 14 in the present application filters the spot change signal through the fourth resistor R4, the first capacitor C1, the fifth resistor R5, the sixth resistor R6, the second capacitor C2, the third capacitor C3, the operational amplifier 102, the variable resistor RF1, and the terminal block P2 to obtain the filtered spot change signal, thereby avoiding large fluctuations in the voltage of the spot change signal and improving the accuracy of the spot change signal.

[0045] Among them, the operational amplifier 102 can be an OPA4192 operational amplifier. The OPA4192 operational amplifier has performances such as four channels, high slew rate, and low noise, and can be used as the first-stage amplifier and the second-stage amplifier for the measurement current signal output by the four-quadrant detector, effectively reducing the number of chips in the circuit.

[0046] In addition, the transfer function of the filtering unit 14 can be expressed as:

[0047] If β is replaced with the transfer function of a twin-T network, the transfer function is:

[0048] where , that is:

[0049] When is satisfied , the frequency of can be filtered out at this time. For other frequencies, is approximately 1, allowing signals of other frequencies to pass through. K is the feedback coefficient of the circuit, where 0 ≤ K ≤ 1. As long as the value of K is selected as a positive number less than 1 and very close to 1, the Q value of the filtering unit 14 can be significantly increased, achieving a narrow-band filtering effect and a high Q value, so that the performance of the filtering unit 14 reaches the best. The vertical arm of the twin-T network is connected to the output terminal of the operational amplifier, and the operational amplifier feeds back a part of the output signal of A2 to the vertical arm of the twin-T network to form a bootstrap, thereby introducing positive feedback. The Q value will increase with the increase of the feedback amount, narrowing the stopband of the notch filter and increasing the Q value. When K = 0, that is, there is no positive feedback, the active notch filter becomes a passive notch filter with Q = 1 / 4. The closer K is to 1, the larger the Q value. By adjusting the voltage division ratio of (1 - K)R and KR, the Q value can be effectively adjusted.

[0050] Exemplarily, the filtering unit 14 can adopt a twin-T notch filter with positive feedback. For the twin-T notch filter, the designed notch frequency is , the value of K is close to 1, and a twin-T structure with positive feedback is used. One of the parameters of the resistor and the capacitor can be set arbitrarily. For example, first, the resistance values of the fourth resistor R4 and the fifth resistor R5 are set to be equal, and is selected to be . Secondly, according to the notch frequency , the capacitance value of the first capacitor C1 is calculated through the following formula and the capacitance value of the second capacitor C2 is .

[0051]

[0052] In addition, the calculation formula for the capacitance value of the third capacitor C3 is , and the calculation formula for the K value of the feedback network is as follows: .

[0053] In some embodiments, the measured voltage signals include a first measured voltage signal, a second measured voltage signal, a third measured voltage signal, and a fourth measured voltage signal. Among them, the first measured voltage signal is the signal corresponding to the first quadrant region in the quadrant detector, the second measured voltage signal is the signal corresponding to the second quadrant region in the quadrant detector, the third measured voltage signal is the signal corresponding to the third quadrant region in the quadrant detector, and the fourth measured voltage signal is the signal corresponding to the fourth quadrant region in the quadrant detector.

[0054] In some embodiments, as Figure 6 shown, the logic unit 13 includes a first addition subunit 15, a second addition subunit 16, a third addition subunit 17, a subtraction subunit 18, and a division subunit 19.

[0055] Among them, the first addition subunit 15 is connected to the gain unit 12 and is configured to perform an addition operation on the first measured voltage signal and the third measured voltage signal to obtain a first operation result; the second addition subunit 16 is connected to the gain unit 12 and is configured to perform an addition operation on the second measured voltage signal and the fourth measured voltage signal to obtain a second operation result; the third addition subunit 17 is connected to the first addition subunit 15 and the second addition subunit 16 and is configured to perform an addition operation on the first operation result and the second operation result to obtain a third operation result; the subtraction subunit 18 is connected to the first addition subunit 15 and the second addition subunit 16 and is configured to perform a subtraction operation on the first operation result and the second operation result to obtain a fourth operation result; the division subunit 19 is connected to the third addition subunit 17, the subtraction subunit 18, and the filtering unit 14 and is configured to obtain a spot change signal according to the third operation result and the fourth operation result.

[0056] Specifically, as Figure 7As shown in the figure, the cross-group amplification unit 11 performs cross-group amplification processing on each measured current signal and converts each measured current signal into a measured voltage signal. The measured voltage signals include a first measured voltage signal A, a second measured voltage signal B, a third measured voltage signal C, and a fourth measured voltage signal D. The gain unit 12 performs adaptive amplification on the first measured voltage signal A, the second measured voltage signal B, the third measured voltage signal C, and the fourth measured voltage signal D. The first adder subunit 15 performs an addition operation on the first measured voltage signal A and the third measured voltage signal C to obtain a first operation result, which can be expressed as A + C. The second adder subunit 16 performs an addition operation on the second measured voltage signal B and the fourth measured voltage signal D to obtain a second operation result, which can be expressed as B + D. The third adder subunit 17 performs an addition operation on the first operation result and the second operation result to obtain a third operation result, which can be expressed as A + C + B + D. The subtraction subunit 18 performs a subtraction operation on the first operation result and the second operation result to obtain a fourth operation result, which can be expressed as A + C - B - D. The division subunit 19 performs a division operation on the third operation result and the fourth operation result to obtain a division operation result, which can be expressed as (A + C - B - D) / (A + C + B + D). The division operation result is used as the spot change signal, and finally, the filtering unit performs filtering processing on the spot change signal.

[0057] In the embodiment, the circuit of the subtraction subunit 18 is as Figure 8 shown. The subtraction operation can be decomposed into in-phase addition and anti-phase addition. The calculation formula for anti-phase addition is as follows:

[0058] First, configure the fifteenth resistor R15. The fifteenth resistor R15 is a balancing resistor, such that , can be expressed as .

[0059] When , , at this time , and the calculation formula for in-phase addition is as follows.

[0060]

[0061] The output voltage has the following calculation formula:

[0062] Under the condition of , the calculation formula for the output voltage is as follows:

[0063] In an embodiment, = = 1K, then , thereby implementing a subtraction circuit, wherein is capable of inputting a measured voltage signal.

[0064] In an embodiment, in the addition sub-unit, the measured voltage signals that need to perform addition operations are connected in parallel to the inverting input terminal of the operational amplifier 102 of the subtraction sub-unit 18 to achieve addition operations.

[0065] In some embodiments, as Figure 9 shown, the division sub-unit 19 includes a divider 103, a fourth capacitor C4, a fifth capacitor C5, a seventh resistor R7, a sixth capacitor C6, and a seventh capacitor C7.

[0066] Among them, the first input terminal X1 of the divider 103 is connected to the subtraction sub-unit 18. The second input terminal X2 of the divider 103, the voltage control terminals (U0, U1, and U2) of the divider 103, and the third input terminal Y1 of the divider 103 are commonly connected and then grounded. The fourth input terminal Z2 of the divider 103 is connected to the third addition sub-unit 17. The divider 103 can use an AD734 chip. The first end of the fourth capacitor C4 is connected to the negative power supply terminal VN of the divider 103 and the negative terminal of the power supply VCC. The second end of the fourth capacitor C4 is connected to the fifth input terminal Z1 of the divider 103 and then grounded. The first end of the fifth capacitor C5 is grounded. The second end of the fifth capacitor C5 is connected to the positive power supply terminal VP of the divider 103 and the positive terminal of the power supply VCC. The first end of the seventh resistor R7 is connected to the output terminal W of the divider 103, the sixth input terminal Y2 of the divider 103, and the filtering unit 14. The second end of the seventh resistor R7 is grounded. The first end of the sixth capacitor C6 is connected to the first end of the seventh resistor R7. The second end of the sixth capacitor C6 is grounded. The first end of the seventh capacitor C7 is connected to the first end of the sixth capacitor C6. The second end of the seventh capacitor C7 is grounded. Thus, the division sub-unit 19 in the present application realizes division operations through the divider 103, the fourth capacitor C4, the fifth capacitor C5, the seventh resistor R7, the sixth capacitor C6, and the seventh capacitor C7.

[0067] In an embodiment, if the input at the first input terminal X1 of the divider 103 is positive, a negative feedback path is established in the division sub-unit 19. The voltage control terminals of the divider 103 and the third input terminal Y1 of the divider 103 are commonly connected and then grounded, but the third input terminal Y1 can also be used as a bias for calculation. The calculation process of the division sub-unit 19 is as follows:

[0068] Among them, W is the output of the division sub-unit 19.

[0069] In some embodiments, as Figure 10 shown, the zoom lens group 3 includes a plano-convex lens 31 and a plano-concave lens 32.

[0070] Among them, the plano-convex lens 31 is located on the outgoing light path of the beam splitter 2 and is used to focus the ranging incident light beam; the plano-concave lens 32 is located on the outgoing light path of the plano-convex lens 31 and is used to diverge the ranging incident light beam; the materials of the plano-convex lens 31 and the plano-concave lens 32 can be H-K9L. That is to say, since the focal plane of the ranging incident light beam needs to match the focal plane of the exposure light beam, when the two do not match, by adjusting the distance between the plano-convex lens 31 and the plano-concave lens 32, the focal plane of the ranging incident light beam can be changed so that the focal plane of the ranging incident light beam matches the focal plane of the exposure light beam.

[0071] In some embodiments, as Figure 1 shown, the cylindrical lens group 5 includes a first cylindrical convex lens 51 and a second cylindrical convex lens 52.

[0072] Among them, the first cylindrical convex lens 51 is arranged on the transmission light path of the beam splitter 2 and is used to focus the ranging reflected light beam; the second cylindrical convex lens 52 is arranged on the outgoing light path of the first cylindrical convex lens 51 and is used to focus the focused ranging reflected light beam. The cylindrical lens group 5 focuses the ranging reflected light beam in two directions, and the focusing positions are staggered in the light path propagation direction. When the plane to be exposed is defocused, the incident angle of the ranging reflected light beam on the cylindrical lens group changes, and then the shape of the test light spot changes.

[0073] In some embodiments, as Figure 1 shown, the optical ranging device 10 further includes a beam expander 8.

[0074] Among them, the beam expander 8 is arranged on the outgoing light path of the laser 1 and is located between the beam splitter 2 and the laser 1, and is used to expand the ranging incident light beam, that is, to expand the diameter of the ranging incident light beam and reduce the divergence angle of the ranging incident light beam, so that the ranging incident light beam is more stable during transmission, and the measurement accuracy and accuracy are improved.

[0075] In an embodiment, as Figure 1 shown, the beam expander 8 is composed of a meniscus lens 81 and a plano-convex lens 82, and the materials of the meniscus lens 81 and the plano-convex lens 82 can be H-K9L. The beam expansion multiple of the beam expander 8 can be 4 times.

[0076] In an embodiment, the data of the ranging lens in the optical ranging device 10 are shown in the following table.

[0077]

[0078] In a second aspect embodiment of the present invention, a laser direct writing exposure machine 100 is provided. Refer to Figure 10 As shown, the laser direct writing exposure machine 100 includes the optical ranging device 10 and the exposure objective lens 20 of the above embodiment.

[0079] Among them, the exposure objective lens 20 is arranged on the exit optical path of the optical ranging device 10 and is used to converge the ranging incident light beam output by the optical ranging device 10 to the plane to be exposed. The exposure objective lens 20 is a common part of the ranging incident optical path and the exposure optical path of the optical ranging device 10. When the exposure light beam is focused on the plane to be exposed through the exposure objective lens 20, it can pass through the short-wave pass filter of the optical ranging device 10 and transmit to the exposure objective lens 20. Thus, the optical ranging device 10 will not affect the exposure operation.

[0080] According to the laser direct writing exposure machine 100 of the embodiment of the present invention, the use of the optical ranging device 10 can effectively improve the measurement accuracy of the optical ranging device 10, and the optical ranging device 10 has low cost, few optical components, and small volume, and is suitable for dynamic measurement scenarios.

[0081] In the description of this specification, the description of reference terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example.

[0082] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and purposes of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. An optical ranging device, characterized in that, Comprising: A laser for emitting a ranging incident light beam; A beam splitter disposed on the outgoing light path of the laser for reflecting or transmitting the ranging incident light beam; A zoom lens group disposed on the reflected light path of the beam splitter for adjusting the focusing position of the ranging incident light beam reflected by the beam splitter; A short-wave pass filter disposed on the outgoing light path of the zoom lens group for reflecting the focused ranging incident light beam to the plane to be exposed and receiving the ranging reflected light beam reflected by the plane to be exposed based on the ranging incident light beam; A cylindrical lens group disposed on the transmitted light path of the beam splitter for focusing the ranging reflected light beam transmitted by the beam splitter; A detector disposed on the light output side of the cylindrical lens group for outputting a measurement current signal according to the ranging reflected light beam; A control module connected to the detector for determining the drift amount of the plane to be exposed according to the measurement current signal.

2. The optical ranging device according to claim 1, wherein The detector is a quadrant detector for forming a ranging light spot according to the ranging reflected light beam and generating a measurement current signal corresponding to each quadrant region according to the area change of the ranging light spot in each quadrant region; The control module is specifically configured to process a plurality of measurement current signals to obtain a light spot change signal and determine the drift amount of the plane to be exposed according to the light spot change signal.

3. The optical distance measuring device according to claim 2, characterized in that, The control module includes: A cross-group amplification unit connected to the quadrant detector for amplifying each measurement current signal to output a corresponding measurement voltage signal; A gain unit connected to the cross-group amplification unit for gaining each measurement voltage signal to obtain a gained measurement voltage signal; A logic unit connected to the gain unit for performing a logic operation on each gained measurement voltage signal to obtain the light spot change signal; A filtering unit connected to the logic unit for filtering the light spot change signal to obtain a filtered light spot change signal.

4. The optical distance measuring device according to claim 3, wherein The gain unit includes a plurality of gain sub-units, and each gain sub-unit includes: A power tube, the gate of which is connected to the output end of the cross-group amplification unit, and the drain of which is connected to a preset power supply; An analog multiplexer, the control end of which is connected to the source of the power tube, the output end of which is connected to the logic unit, the ground end and the negative power supply end of the analog multiplexer are grounded, and the positive power supply end of the analog multiplexer is connected to a power supply; A first resistor, the first end of which is connected to the source of the power tube and the control end of the analog multiplexer, and the second end of which is grounded; A second resistor, a first end of the second resistor is connected to a first input end of the analog multiplexer, and a second end of the second resistor is connected to an output end of the cross-group amplification unit; A third resistor, a first end of the third resistor is connected to a second input end of the analog multiplexer, and a second end of the third resistor is connected to the output end of the cross-group amplification unit.

5. The optical distance measuring device according to claim 3, characterized in that, The filtering unit includes: A fourth resistor, a first end of the fourth resistor is connected to an output end of the logic unit; A first capacitor, a first end of the first capacitor is connected to the output end of the logic unit and the first end of the fourth resistor; A fifth resistor, a first end of the fifth resistor is connected to a second end of the fourth resistor; A sixth resistor, a first end of the sixth resistor is connected to a second end of the first capacitor; A second capacitor, a first end of the second capacitor is connected to the first end of the sixth resistor and the second end of the first capacitor, and a second end of the second capacitor is connected to a second end of the fifth resistor; A third capacitor, a first end of the third capacitor is connected to the second end of the fourth resistor and the first end of the fifth resistor, and a second end of the third capacitor is connected to a second end of the sixth resistor; An operational amplifier, a first non-inverting input end of the operational amplifier is connected to the second end of the fifth resistor and the second end of the second capacitor, a first inverting input end of the operational amplifier is connected to the second end of the sixth resistor, the second end of the third capacitor, and a first output end of the operational amplifier, a second output end of the operational amplifier is connected to a second inverting input end of the operational amplifier, a third output end of the operational amplifier is connected to a third inverting input end of the operational amplifier to output the filtered spot change signal, and a power supply end of the operational amplifier is connected to a power supply; A rheostat, a fixed end of the rheostat is connected to the second output end of the operational amplifier and the second inverting input end of the operational amplifier, an adjustable end of the rheostat is connected to a second non-inverting input end of the operational amplifier, and a sliding end of the rheostat is grounded; A terminal block, a first terminal of the terminal block is grounded, and a second terminal of the terminal block is connected to the second output end of the operational amplifier, the second inverting input end of the operational amplifier, and the fixed end of the rheostat.

6. The optical ranging device according to claim 3, wherein The measurement voltage signal includes a first measurement voltage signal, a second measurement voltage signal, a third measurement voltage signal, and a fourth measurement voltage signal. Among them, the first measurement voltage signal is a signal corresponding to the first quadrant region in the quadrant detector, the second measurement voltage signal is a signal corresponding to the second quadrant region in the quadrant detector, the third measurement voltage signal is a signal corresponding to the third quadrant region in the quadrant detector, and the fourth measurement voltage signal is a signal corresponding to the fourth quadrant region in the quadrant detector; The logic unit includes: The first addition subunit, which is connected to the gain unit and is configured to perform an addition operation on the first measurement voltage signal and the third measurement voltage signal to obtain a first operation result; The second addition subunit, which is connected to the gain unit and is configured to perform an addition operation on the second measurement voltage signal and the fourth measurement voltage signal to obtain a second operation result; The third addition subunit, which is connected to the first addition subunit and the second addition subunit and is configured to perform an addition operation on the first operation result and the second operation result to obtain a third operation result; The subtraction subunit, which is connected to the first addition subunit and the second addition subunit and is configured to perform a subtraction operation on the first operation result and the second operation result to obtain a fourth operation result; The division subunit, which is connected to the third addition subunit, the subtraction subunit and the filtering unit and is configured to obtain the spot change signal according to the third operation result and the fourth operation result.

7. The optical distance measuring device according to claim 6, wherein The division subunit includes: A divider, the first input terminal of which is connected to the subtraction subunit, and the second input terminal, the voltage control terminal and the third input terminal of the divider are commonly connected and then grounded, and the fourth input terminal of the divider is connected to the third addition subunit; A fourth capacitor, the first end of which is connected to the negative power supply terminal of the divider and the negative terminal of the power supply, and the second end of the fourth capacitor is connected to the fifth input terminal of the divider and then grounded; A fifth capacitor, the first end of which is grounded, and the second end of the fifth capacitor is connected to the positive power supply terminal of the divider and the positive terminal of the power supply; A seventh resistor, the first end of which is connected to the output terminal of the divider, the sixth input terminal of the divider and the filtering unit, and the second end of the seventh resistor is grounded; A sixth capacitor, the first end of which is connected to the first end of the seventh resistor, and the second end of the sixth capacitor is grounded; A seventh capacitor, the first end of which is connected to the first end of the sixth capacitor, and the second end of the seventh capacitor is grounded.

8. The optical distance measuring device according to claim 1, characterized in that The zoom lens group includes: A plano-convex lens, which is located on the outgoing light path of the beam splitter and is configured to focus the ranging incident light beam; A plano-concave lens, which is located on the outgoing light path of the plano-convex lens and is configured to diverge the ranging incident light beam; The cylindrical lens group includes: A first cylindrical convex lens, which is arranged on the transmission light path of the beam splitter and is configured to focus the ranging reflected light beam; A second cylindrical convex lens, which is arranged on the outgoing light path of the first cylindrical convex lens and is configured to focus the focused ranging reflected light beam.

9. The optical distance measuring device according to claim 1, wherein It further includes: An expander, which is arranged on the outgoing light path of the laser and is located between the beam splitter and the laser and is configured to expand the ranging incident light beam.

10. A laser direct writing exposure machine, characterized in that, It includes: The optical ranging device according to any one of claims 1-9; An exposure objective lens, which is arranged on the outgoing light path of the optical ranging device and is used to converge the ranging incident light beam output by the optical ranging device onto the plane to be exposed.

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