Global detection device for LCoS liquid crystal cell thickness based on low-coherence light Michelson interference

Abstract

The present invention belongs to the technical field of liquid crystal box thickness detection, and in particular discloses a global detection device for the thickness of an LCoS liquid crystal box based on low-coherence light Michelson interference, comprising a nanopositioning stage, an imaging system, a computer, an illumination system, a Michelson interference objective lens and a silicon-based liquid crystal box, wherein the imaging system comprises a first beam splitter prism, an imaging lens and a planar array camera, and the illumination system comprises a low-coherence light source, a condenser lens and a projection lens. The present invention measures the three-dimensional morphology data of the lower surface of the cover glass and the three-dimensional morphology data of the upper surface of the silicon substrate, and fits the three-dimensional morphology data of the two surfaces into a plane, and calculates the coordinate difference of the two fitting planes in the vertical direction to obtain the thickness H of the silicon-based liquid crystal box. Since the device has the characteristics of a large field of view, and the field of view can cover the size of the silicon-based liquid crystal box, it can realize the global measurement of the thickness of the silicon-based liquid crystal box, and the measurement speed is fast, the accuracy is high, and the precision is high.

Description

Technical Field

[0001] The invention belongs to the technical field of liquid crystal box thickness detection, and in particular relates to an LCoS liquid crystal box thickness global detection device based on low-coherence light Michelson interference. Background Art

[0002] Liquid Crystal on Silicon (LCoS) is a reflective liquid crystal micro-panel display technology with the characteristics of high light utilization efficiency, small size, high aperture ratio and mature manufacturing technology. However, in the existing LCoS packaging, LCoS is made of a single piece, and its thickness consistency is not easy to ensure. The thickness is prone to deviation, which easily leads to unqualified products.

[0003] The traditional method for detecting the thickness of the liquid crystal box requires individual detection of each point of the liquid crystal box thickness, and cannot perform global detection of the LCoS liquid crystal box thickness, resulting in low detection efficiency.

[0004] Therefore, it is necessary to invent a global detection device for LCoS liquid crystal box thickness based on low-coherence light Michelson interference to solve the above problems. Summary of the invention

[0005] In view of the above problems, the present invention provides a global detection device for LCoS liquid crystal box thickness based on low-coherence light Michelson interference to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The invention discloses a global detection device for the thickness of an LCoS liquid crystal box based on low-coherence light Michelson interference, comprising a nanopositioning stage, an imaging system, a computer, an illumination system, a Michelson interference objective lens and a silicon-based liquid crystal box, wherein the imaging system comprises a first beam splitter prism, an imaging lens and a planar array camera, the illumination system comprises a low-coherence light source, a condensing lens and a projection lens, the illumination system is connected to the computer via the low-coherence light source, the light emitted by the low-coherence light source is aggregated by the condensing lens, and then projected onto the first beam splitter prism of the imaging system via the projection lens, the first beam splitter prism irradiates the light into the Michelson interference objective lens, the silicon-based liquid crystal box comprises a cover glass, a plurality of spacers and a silicon substrate, liquid crystals are added between the plurality of spacers, and the silicon-based liquid crystal box is placed correspondingly. The nanopositioning stage is placed on the top surface of the nanopositioning stage, which is connected to a computer through a wire. Piezoelectric ceramics are arranged on the nanopositioning stage. The computer controls the operation of the nanopositioning stage. The nanopositioning stage realizes nano-level positioning of the silicon-based liquid crystal box in the vertical direction through the piezoelectric ceramics. Light is irradiated on the silicon-based liquid crystal box through a Michelson interference objective lens. Light reflected from the top surface of the silicon substrate or the bottom surface of the cover glass returns to the inside of the Michelson interference objective lens. Interference light is formed in the Michelson interference objective lens and then transmitted to the first beam splitter prism. The first beam splitter prism images the interference light into the inside of the area array camera through an imaging lens. The area array camera transmits the light intensity data of the interference light to the computer. The computer globally detects the liquid crystal thickness of the silicon-based liquid crystal box according to the light intensity data of the interference light.

[0008] Furthermore, the Michelson interference objective lens comprises a first objective lens, a second objective lens, a third objective lens, a second beam splitter prism, a glass plate and a reflector. The glass plate and the reflector are both arranged vertically, and the inner side of the reflector is coated. After the light passes through the first objective lens, the second objective lens and the third objective lens in sequence and irradiates the second beam splitter prism, a part of the light is transmitted to the reflector through the glass plate, and is reflected by the reflector and returns to the beam splitting surface of the second beam splitter prism to form reference light. Another part of the light irradiates the silicon-based liquid crystal box and is reflected from the top surface of the silicon base plate or the bottom surface of the cover glass to the beam splitting surface of the second beam splitter prism to form test light. The reference light and the test light interfere at the beam splitting surface of the second beam splitter prism, and the interference light is projected into the first beam splitter prism of the imaging system through the Michelson interference objective lens.

[0009] Furthermore, a plurality of spacers are arranged on the top surface of the silicon substrate, a void layer is formed between the plurality of spacers, and the cover glass is correspondingly placed on the top of the plurality of spacers.

[0010] Furthermore, the glass plate and the cover glass have the same thickness and are made of the same material.

[0011] Furthermore, the nanopositioning platform includes a slide and a base plate, and the slide is configured as piezoelectric ceramics, and the slide is connected to a computer through a controller, the slide is at the top of the base plate, a slide groove is provided on the top surface of the base plate, and a slide rail is installed inside the slide groove by screws, a slide bar is provided on the bottom surface of the slide, and the slide bar is inside the slide groove, the silicon-based liquid crystal box is fixedly installed on the top surface of the slide by an installation component, the base plate is connected to a computer by a controller, and when the controller works, the slide uses the slide bar to slide inside the slide groove of the base plate, and the sliding slide drives the silicon-based liquid crystal box to move horizontally synchronously through the installation component.

[0012] Furthermore, the mounting component includes two sets of relative clamping frames, which are respectively located on both sides of the silicon base plate, and the clamping frames include two relative side frames, a cross bar is fixed to one side of the side frame, and the cross bars of the two side frames are relatively matched, and a rotating sleeve is spirally sleeved on the surface of the cross bar, and the two ends of the rotating sleeve are respectively sleeved on the ends of the two cross bars, and the rotating sleeve makes the two cross bars approach or move away from each other.

[0013] Furthermore, a side panel is provided on the other side of the side frame, and the inner side of the side panel corresponds to the side of the silicon substrate, and a plug rod inserted into the inside of the side frame is fixed to the inner side of the side panel. Two side grooves are provided on the outer side of the side frame, and a slider is provided inside the side groove, and the slider is fixedly connected to the plug rod. The movable side panel utilizes the plug rod to drive the slider to move inside the side groove, and a card slot is provided on one side of the side groove, and the slider corresponds to the card slot.

[0014] Furthermore, two pressure plates are arranged on the top of the side frame, and a pressure block is arranged on the bottom surface of the inner end of the pressure plate. The pressure plate is pressed on the top surface of the silicon base plate by the pressure block. A vertical rod penetrating the top of the side groove is fixed to the outer end of the pressure plate, and a wedge block is fixed to the bottom end of the vertical rod. The wedge block corresponds to the slider, and the surface of the vertical rod is sleeved on the spring, the bottom end of the spring is connected to the top surface of the wedge block, and the top end of the spring is connected to the inner top of the side groove. The bottom surface of the wedge block and the top surface of the slider are both inclined, and the slider moving into the slot gradually moves away from the wedge block, and the elastic force of the spring causes the wedge block to move down inside the side groove.

[0015] Furthermore, the two wedge blocks are fixedly connected by a connecting plate, a screw rod runs through the center of the connecting plate, and the bottom end of the screw rod is spirally inserted into the top surface of the slide table.

[0016] Technical effects and advantages of the present invention:

[0017] 1. The present invention measures the three-dimensional morphology data of the lower surface of the cover glass and the three-dimensional morphology data of the upper surface of the silicon substrate, and fits the three-dimensional morphology data of the two surfaces into a plane, and calculates the coordinate difference of the two fitting planes in the vertical direction to obtain the thickness H of the silicon-based liquid crystal box. Since the device has the characteristics of a large field of view, and the field of view can cover the size of the silicon-based liquid crystal box, it can achieve global measurement of the thickness of the silicon-based liquid crystal box with fast measurement speed, high accuracy and high precision.

[0018] 2. After replacing the cover glass on the top of the silicon-based liquid crystal box, the present invention selects a glass plate in the adapted Michelson interference objective lens according to the thickness and material of the new cover glass, so as to facilitate the thickness detection of the LCoS liquid crystal box with different cover glasses through the light of the Michelson interference objective lens.

[0019] 3. The present invention ensures the stability of the silicon-based substrate on the top of the slide table by cooperating with the screw and the clamp, thereby completing the limitation of the silicon-based liquid crystal box.

[0020] 4. In the present invention, both side frames use side plates to limit and clamp the silicon substrate, so that the clamps can be easily adapted to silicon substrates of different sizes. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 1 is an overall schematic diagram of a global detection device for LCoS liquid crystal box thickness based on low-coherence light Michelson interference according to an embodiment of the present invention;

[0022] Figure 2 is a low-coherence light interference intensity curve and a fitted envelope curve diagram of an embodiment of the present invention;

[0023] Figure 3 is a schematic diagram of the liquid crystal box thickness measurement principle of an embodiment of the present invention;

[0024] Figure 4 is a three-dimensional data diagram of the upper and lower surface morphologies of a liquid crystal cell according to an embodiment of the present invention;

[0025] Figure 5 3D data curves and fitted envelope straight line diagrams of the upper and lower surface morphologies of a liquid crystal cell according to an embodiment of the present invention;

[0026] Figure 6 is a schematic diagram of a silicon-based liquid crystal cell according to an embodiment of the present invention being placed on top of a slide table;

[0027] Figure 7 is an overall schematic diagram of a side frame according to an embodiment of the present invention;

[0028] Figure 8 is a schematic diagram of the internal components of a side frame according to an embodiment of the present invention;

[0029] In the figure: 1, low coherence light source; 2, focusing lens; 3, projection lens; 4, first beam splitter prism; 401, imaging system; 5, first objective lens; 6, second objective lens; 7, third objective lens; 8, second beam splitter prism; 9, glass plate; 10, reflector; 11, cover glass; 12, spacer; 13, silicon substrate; 14, nanopositioning stage; 15, imaging lens; 16, area array camera; 17, computer; 18, illumination system; 19, Michelson interference objective lens; 20, silicon-based liquid crystal box; 21, slide; 22, bottom plate; 23, slide rail; 24, slide bar; 25, side frame; 26, cross bar; 27, rotating sleeve; 28, side plate; 29, plug rod; 30, slider; 31, pressure plate; 32, pressure block; 33, vertical rod; 34, wedge block; 35, spring; 36, screw. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments.

[0031] The present invention provides a global detection device for LCoS liquid crystal box thickness based on low-coherence light Michelson interference, such as Figure 1 As shown, it includes a nanopositioning stage 14, an imaging system 401, a computer 17, and an illumination system 18. The illumination system 18 is configured as a Kohler illumination system, a Michelson interference objective lens 19, and a silicon-based liquid crystal box 20. The imaging system 401 includes a first beam splitter prism 4, an imaging lens 15, and a planar array camera 16. The illumination system 18 includes a low-coherence light source 1, a focusing lens 2, and a projection lens 3. The illumination system 18 is connected to the computer 17 via the low-coherence light source 1. The light emitted by the low-coherence light source 1 is aggregated by the focusing lens 2 and then projected onto the first beam splitter prism 4 of the imaging system 401 via the projection lens 3. The first beam splitter prism 4 irradiates the light into the inside of the Michelson interference objective lens 19. The Michelson interference objective lens 19 includes a first objective lens 5, a second objective lens 6, a third objective lens 7, a second dichroic prism 8, a glass plate 9 and a reflector 10, wherein the glass plate 9 is configured as a compensation glass plate, the glass plate 9 and the reflector 10 are both vertically arranged, and the inner side of the reflector 10 is coated, and the light reflected by the reflector 10 is returned to the second dichroic prism 8 through the glass plate 9 to form a reference light.

[0032] The silicon-based liquid crystal box 20 includes a cover glass 11, a plurality of spacers 12 and a silicon base plate 13. Liquid crystals are added between the plurality of spacers 12. The silicon-based liquid crystal box 20 is placed on the top surface of a nanopositioning stage 14. The nanopositioning stage 14 is connected to a computer 17 via a wire. Piezoelectric ceramics are arranged on the nanopositioning stage 14. The computer 17 controls the operation of the nanopositioning stage 14. The nanopositioning stage 14 realizes nano-level positioning of the silicon-based liquid crystal box 20 in a vertical direction through piezoelectric ceramics, that is, drives the silicon-based liquid crystal box 20 to move up and down in a vertical (Z-axis) direction, so as to facilitate scanning and detection of the silicon-based liquid crystal box 20 in a vertical direction.

[0033] The computer 17 controls the operation of the nanopositioning stage 14. The nanopositioning stage 14 uses piezoelectric ceramics to move the silicon-based liquid crystal box 20 up and down in the vertical direction. The first beam splitter prism 4 transmits light to the Michelson interference objective lens 19. The light passes through the first objective lens 5, the second objective lens 6, and the third objective lens 7 in sequence and then irradiates the second beam splitter prism 8. A part of the light is transmitted to the reflector 10 through the glass plate 9, and is reflected by the reflector 10 and returns to the beam splitting surface of the second beam splitter prism 8 to form reference light. The other part of the light irradiates the silicon-based liquid crystal box 20 and is reflected from the top surface of the silicon base plate 13 or the bottom surface of the cover glass 11 to the beam splitting surface of the second beam splitter prism 8 to form test light. The reference light and the test light interfere at the beam splitting surface of the second beam splitter prism 8, and the interference light is projected to the first beam splitter prism 4 of the imaging system 401 through the Michelson interference objective lens 19.

[0034] The first beam splitter prism 4 images the interference light into the area array camera 16 through the imaging lens 15. The area array camera 16 transmits the light intensity data of the interference light to the computer 17. The computer 17 globally detects the liquid crystal thickness of the silicon-based liquid crystal box 20 based on the light intensity data of the interference light.

[0035] Exemplarily, the upper surface of the cover glass 11 is coated with an anti-reflection film, and the lower surface is coated with an ITO conductive film. The integrated circuit is integrated on the top surface of the silicon substrate 13 using CMOS technology, and an aluminum reflective layer is coated on the surface of the silicon substrate 13. Spacers 12 are provided around the edges of the top surface of the silicon substrate 13 to separate the cover glass 11 and the silicon substrate 13. The empty layer formed between the multiple spacers 12 is used to inject liquid crystal. A single-layer metal reflective layer is coated on the surface of the reflector 10. The light irradiating the surface of the reflector 10 is completely reflected into the second beam splitter prism 8 through the glass plate 9. The glass plate 9 and the cover glass 11 are made of the same material and have the same thickness. The light reflected by the reflector 10 is compensated by the glass plate 9 to avoid scattering of the reflected light, thereby forming interference light on the beam splitter surface of the second beam splitter prism 8. The glass plate 9 in the reference optical path and the cover glass 11 in the test optical path have the same optical path, so that the reference optical path and the test optical path can easily meet the equal optical path condition, so that the low coherence light can interfere on the splitting surface of the second splitter prism 8.

[0036] The glass plate 9 is correspondingly inserted between the second beam splitter prism 8 and the reflector 10, and the position of the glass plate 9 can be moved horizontally, and the moved glass plate 9 does not affect the lighting effect between the second beam splitter prism 8 and the reflector 10. After replacing the cover glass 11 on the top of the silicon-based liquid crystal cell 20, an appropriate glass plate 9 is selected according to the thickness and material of the new cover glass 11, so that the thickness of the silicon-based liquid crystal cell 20 with different cover glasses can be detected by the light of the Michelson interference objective lens 19.

[0037] exist Figure 2 and Figure 3 In the envelope fitting algorithm, we get Figure 2 The fitting envelope curve corresponding to the interference light in the vertical direction (Z axis) of the liquid crystal is obtained. Among them, the nanopositioning stage 14 drives the silicon-based liquid crystal box 20 to move up and down at the nanometer level in the vertical direction through piezoelectric ceramics, which can form a change in the intensity of the interference light on the lower surface of the cover glass 11 or the upper surface of the silicon substrate 13, and obtain Figure 3 The interference light intensity curve in the image is changed to obtain the maximum value point of the interference light on the lower surface of the cover glass 11 and the maximum value point on the upper surface of the silicon substrate 13. The height difference between the two maximum value points is the liquid crystal thickness of the silicon-based liquid crystal box 20. Figure 2 In the figure, the Z axis is the direction perpendicular to the Si-based liquid crystal cell 20 , and the I axis is the interference light intensity in the vertical direction of the Si-based liquid crystal cell 20 .

[0038] exist Figure 4 and Figure 5 In the example, the light intensity data of the interference light is used to obtain the 3D data of the morphology of the lower surface of the cover glass 11 and the upper surface of the silicon base plate 13 in the silicon-based liquid crystal cell 20, and the linear fitting algorithm is used to obtain Figure 5The fitting straight line corresponding to the three-dimensional data of the morphology. Figure 5 As shown, by measuring the 3D topography data of the lower surface of the cover glass 11 and the upper surface of the silicon base plate 13, and fitting the 3D topography data of the two surfaces into a plane, the thickness H of the silicon-based liquid crystal box 20 is calculated by calculating the coordinate difference of the two fitting planes in the vertical (Z-axis) direction. Since the device has the characteristics of a large field of view, and the field of view can cover the size of the silicon-based liquid crystal box 20, it is possible to achieve global measurement of the thickness of the silicon-based liquid crystal box 20, with fast measurement speed and high efficiency. Figure 4 and Figure 5 In the figure, the X-axis is the front-to-back direction of the LCOS cell 20 , and the Y-axis is the left-to-right direction of the LCOS cell 20 .

[0039] exist Figure 1 and Figure 6 In the figure, the nanopositioning platform 14 includes a slide 21 and a base plate 22, and the slide 21 is configured as a piezoelectric ceramic, and the slide 21 is connected to the computer 17 through a controller. The nanopositioning platform 14 realizes nano-level up and down movement of the silicon-based liquid crystal box 20 in the vertical direction through the slide 21. The slide 21 is at the top of the base plate 22. A slide groove is arranged on the top surface of the base plate 22, and a slide rail 23 is installed inside the slide groove by screws. A slide bar 24 is arranged on the bottom surface of the slide 21, and the slide bar 24 is inside the slide groove. The silicon-based liquid crystal box 20 is fixedly installed on the top surface of the slide 21 through an installation component. The base plate 22 is connected to the computer 17 by a controller. When the controller works, the slide 21 slides inside the slide groove of the base plate 22 by using the slide bar 24. The sliding slide 21 drives the silicon-based liquid crystal box 20 to move horizontally synchronously through the installation component. After the nanopositioning platform 14 is installed on the top surface of the slide 21 through the installation components, the controller controls the movement of the slide 21. The slide 21 slides inside the slide groove using the slide 24, and the slide 24 and the slide rail 23 are slid together to achieve translation of the slide 21.

[0040] exist Figure 6 and Figure 7In the figure, the mounting component includes two sets of opposite clamps, which are respectively located on both sides of the silicon base plate 13. The clamps include two opposite side frames 25. A cross bar 26 is fixed on one side of the side frame 25, and the cross bars 26 of the two side frames 25 are relatively matched. A rotating sleeve 27 is spirally sleeved on the surface of the cross bar 26, and the two ends of the rotating sleeve 27 are respectively sleeved on the ends of the two cross bars 26. The rotating sleeve 27 makes the two cross bars 26 approach or move away from each other. The silicon-based liquid crystal box 20 is placed on the top surface of the slide 21 through the silicon base plate 13, and the two clamping frames are placed on both sides of the silicon base plate 13 opposite to each other. At this time, the inner side of the side frame 25 is in contact with the side of the silicon base plate 13, and the rotating sleeve 27 is screwed. Since the two side frames 25 are placed on the top surface of the slide 21 accordingly, the cross bar 26 is prevented from rotating with the rotating sleeve 27. The spiral cooperation between the rotating rotating sleeve 27 and the cross bar 26 makes the two opposite cross bars 26 approach each other, and the moving cross bar 26 drives the side frames 25 to move synchronously. At this time, the two opposite side frames 25 approach each other.

[0041] exist Figure 6 and Figure 7 In the figure, a side plate 28 is provided on the other side of the side frame 25, and the inner side of the side plate 28 corresponds to the side of the silicon substrate 13. A plug rod 29 inserted into the inside of the side frame 25 is fixed on the inner side of the side plate 28. Two side grooves are provided on the outer side of the side frame 25. A slider 30 is provided inside the side groove, and the slider 30 is fixedly connected to the plug rod 29. The moving side plate 28 drives the slider 30 to move inside the side groove by the plug rod 29. A card slot is provided on one side of the side slot, and the slider 30 corresponds to the card slot. The moving side frame 25 drives the side plate 28 to approach the side edge of the silicon substrate plate 13 until the inner side surface of the side plate 28 fits with the side edge of the silicon substrate plate 13, and the side frame 25 continues to move, and the side frame 25 gradually separates from the side plate 28, and the side frame 25 slides on the surface of the plug rod 29, and the side frame 25 moves on the surface of the slider 30 through the side groove until the slot of the side frame 25 corresponds to the matching slider 30, at which time the slider 30 and the slot cooperate to limit the plug rod 29, and the moving side frame 25 uses the slider 30 and the plug rod 29 to pull the side plate 28 to squeeze the side edge of the silicon substrate plate 13, and the two opposite side frames 25 both use the side plates 28 to limit and clamp the silicon substrate plate 13, so that the clamping frame can adapt to silicon substrate plates 13 of different sizes.

[0042] exist Figures 6 to 8In the embodiment, two pressure plates 31 are arranged on the top of the side frame 25, and a pressure block 32 is arranged on the bottom surface of the inner end of the pressure plate 31. The pressure plate 31 is pressed on the top surface of the silicon base plate 13 by the pressure block 32. A vertical rod 33 penetrating the top of the side groove is fixed to the outer end of the pressure plate 31, and a wedge block 34 is fixed to the bottom end of the vertical rod 33. The wedge block 34 corresponds to the slider 30. The surface of the vertical rod 33 is sleeved on the spring 35. The bottom end of the spring 35 is connected to the top surface of the wedge block 34, and the top end of the spring 35 is connected to the inner top of the side groove. The bottom surface of the wedge block 34 and the top surface of the slider 30 are both inclined. The slider 30 moving into the slot gradually moves away from the wedge block 34, and the elastic force of the spring 35 causes the wedge block 34 to move downward inside the side groove. When the moving side frame 25 slides on the outside of the slider 30, the side frame 25 uses the vertical rod 33 to drive the wedge block 34 to move synchronously. At this time, the wedge block 34 and the slider 30 produce relative movement, and the elastic force of the spring 35 makes the inclined surface of the wedge block 34 always fit the inclined surface of the slider 30. The wedge block 34 slides on the inclined surface of the slider 30 using the inclined surface. At this time, the elastic force of the spring 35 causes the wedge block 34 to move downward. The downwardly moved wedge block 34 uses the vertical rod 33 to pull the pressure plate 31 downward until the pressure block 32 at the bottom of the pressure plate 31 is correspondingly pressed on the top surface of the silicon base plate 13. At this time, the wedge block 34 stops moving downward, and the side frame 35 that continues to move drives the wedge block 34 to separate from the slider 30 until the side frame 25 pulls the side plate 28 to squeeze the side of the silicon base plate 13 through the slider 30 and the insertion rod 29. At this time, the side frame 25 stops moving, and the elastic force of the spring 35 causes the pressure block 32 to squeeze the silicon base plate 13, thereby ensuring the initial limitation of the side frame 25.

[0043] The two wedge blocks 34 are fixedly connected by a connecting plate, and a screw rod 36 is passed through the center of the connecting plate, and the bottom end of the screw rod 36 is screwed into the top surface of the slide 21. The screw rod 36 passes through the connecting plate until the bottom end of the screw rod 36 is screwed into the top surface of the slide 21. The screw rod 36 cooperates with the slide 21 to make the wedge block 34 continue to move downward. The wedge block 34 drives the pressing block 32 at the bottom of the pressing plate 31 to squeeze the top surface of the silicon base plate 13 by using the vertical rod 33, thereby improving the stability of the silicon base plate 13 on the top of the slide 21, and completing the limitation of the silicon-based liquid crystal box 20.

[0044] Working principle of the present invention:

[0045] Reference Figures 1 to 8 As shown, the silicon-based liquid crystal box 20 is placed on the top surface of the slide 21 through the silicon base plate 13, and the two clamping frames are placed on both sides of the silicon base plate 13 relatively. At this time, the inner side of the side frame 25 is in contact with the side of the silicon base plate 13, and the rotating sleeve 27 is screwed. Since the two side frames 25 are placed on the top surface of the slide 21 accordingly, the cross bar 26 is prevented from rotating with the rotating sleeve 27. The spiral cooperation between the rotating rotating sleeve 27 and the cross bar 26 makes the two opposite cross bars 26 approach each other, and the moving cross bar 26 drives the side frames 25 to move synchronously. At this time, the two opposite side frames 25 approach each other.

[0046] The moving side frame 25 drives the side plate 28 to approach the side edge of the silicon substrate plate 13 until the inner side surface of the side plate 28 fits with the side edge of the silicon substrate plate 13, and the side frame 25 continues to move, and the side frame 25 gradually separates from the side plate 28, and the side frame 25 slides on the surface of the plug rod 29, and the side frame 25 moves on the surface of the slider 30 through the side groove until the slot of the side frame 25 corresponds to the matching slider 30, at which time the slider 30 and the slot cooperate to limit the plug rod 29, and the moving side frame 25 uses the slider 30 and the plug rod 29 to pull the side plate 28 to squeeze the side edge of the silicon substrate plate 13, and the two opposite side frames 25 both use the side plates 28 to limit and clamp the silicon substrate plate 13, so that the clamping frame can adapt to silicon substrate plates 13 of different sizes.

[0047] When the moving side frame 25 slides on the outside of the slider 30, the side frame 25 uses the vertical rod 33 to drive the wedge block 34 to move synchronously. At this time, the wedge block 34 and the slider 30 produce relative movement, and the elastic force of the spring 35 makes the inclined surface of the wedge block 34 always fit the inclined surface of the slider 30. The wedge block 34 slides on the inclined surface of the slider 30 using the inclined surface. At this time, the elastic force of the spring 35 causes the wedge block 34 to move downward. The downwardly moved wedge block 34 uses the vertical rod 33 to pull the pressure plate 31 downward until the pressure block 32 at the bottom of the pressure plate 31 is correspondingly pressed on the top surface of the silicon base plate 13. At this time, the wedge block 34 stops moving downward, and the side frame 35 that continues to move drives the wedge block 34 to separate from the slider 30 until the side frame 25 pulls the side plate 28 to squeeze the side of the silicon base plate 13 through the slider 30 and the insertion rod 29. At this time, the side frame 25 stops moving, and the elastic force of the spring 35 causes the pressure block 32 to squeeze the silicon base plate 13, thereby ensuring the initial limitation of the side frame 25. The screw 36 is passed through the connecting plate until the bottom end of the screw 36 is screwed on the top surface of the slide 21. The screw 36 cooperates with the slide 21 to make the wedge block 34 continue to move downward. The wedge block 34 uses the vertical rod 33 to drive the pressing block 32 at the bottom of the pressing plate 31 to squeeze the top surface of the silicon base plate 13, thereby improving the stability of the silicon base plate 13 on the top of the slide 21 and completing the limitation of the silicon-based liquid crystal box 20.

[0048] After the silicon-based liquid crystal box 20 is installed on the top surface of the slide 21, the controller controls the movement of the slide 21, and the sliding cooperation between the slide bar 24 and the slide rail 23 is used to realize the translation of the slide 21. The nanopositioning stage 14 realizes nano-level positioning of the silicon-based liquid crystal box 20 in the vertical direction through piezoelectric ceramics.

[0049] The light emitted by the low coherence light source 1 is converged by the condenser lens 2 and then projected onto the first beam splitter prism 4 by the projection lens 3. The first beam splitter prism 4 transmits the light to the Michelson interference objective lens 19. After the light passes through the first objective lens 5, the second objective lens 6, and the third objective lens 7 in sequence and irradiates the second beam splitter prism 8, a part of the light is transmitted to the reflector 10 through the glass plate 9, and is reflected by the reflector 10 and returns to the beam splitting surface of the second beam splitter prism 8 to form reference light. The other part of the light irradiates the silicon-based liquid crystal box 20 and is reflected by the top surface of the silicon base plate 13 or the bottom surface of the cover glass 11 to the beam splitting surface of the second beam splitter prism 8 to form test light. The reference light and the test light interfere at the beam splitting surface of the second beam splitter prism 8, and the interference light is projected to the first beam splitter prism 4 of the imaging system 401 through the Michelson interference objective lens 19. The first beam splitter prism 4 images the interference light into the area array camera 16 through the imaging lens 15. The area array camera 16 transmits the light intensity data of the interference light to the computer 17. The computer 17 globally detects the liquid crystal thickness of the silicon-based liquid crystal box 20 based on the light intensity data of the interference light.

[0050] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them.

Claims

1. A global detection device for LCoS liquid crystal cell thickness based on low-coherence light Michelson interference, characterized in that: The invention comprises a nanopositioning stage (14), an imaging system (401), a computer (17), an illumination system (18), a Michelson interference objective lens (19) and a silicon-based liquid crystal box (20). The imaging system (401) comprises a first beam splitter prism (4), an imaging lens (15) and a planar array camera (16). The illumination system (18) comprises a low-coherence light source (1), a focusing lens (2) and a projection lens (3). The illumination system (18) is connected to the computer (17) via the low-coherence light source (1). 7), after the light emitted by the low coherence light source (1) is concentrated by the focusing lens (2), it is projected onto the first beam splitter prism (4) of the imaging system (401) through the projection lens (3), and the first beam splitter prism (4) irradiates the light into the interior of the Michelson interference objective lens (19), the silicon-based liquid crystal box (20) comprises a cover glass (11), a plurality of spacers (12) and a silicon substrate (13), liquid crystals are added between the plurality of spacers (12), and the silicon-based liquid crystal box (20) is placed correspondingly on the nanostructured substrate (11). The nanopositioning platform (14) is connected to a computer (17) via a wire. The nanopositioning platform (14) is provided with piezoelectric ceramics. The computer (17) controls the operation of the nanopositioning platform (14). The nanopositioning platform (14) realizes nano-level positioning of the silicon-based liquid crystal box (20) in a vertical direction via the piezoelectric ceramics. Light is irradiated on the silicon-based liquid crystal box (20) via a Michelson interference objective lens (19). Light reflected from the top surface of the silicon substrate (13) or the bottom surface of the cover glass (11) returns to the inside of the Michelson interference objective lens (19). Interference light is formed in the Michelson interference objective lens (19) and then transmitted to a first beam splitter prism (4). The first beam splitter prism (4) images the interference light into the inside of a planar array camera (16) via an imaging lens (15). The planar array camera (16) transmits light intensity data of the interference light to the computer (17). The computer (17) globally detects the liquid crystal thickness of the silicon-based liquid crystal box (20) based on the light intensity data of the interference light. The Michelson interference objective lens (19) comprises a first objective lens (5), a second objective lens (6), a third objective lens (7), a second beam splitter prism (8), a glass plate (9) and a reflector (10). The glass plate (9) and the reflector (10) are both arranged vertically, and the inner side surface of the reflector (10) is coated. After light passes through the first objective lens (5), the second objective lens (6) and the third objective lens (7) in sequence and is irradiated on the second beam splitter prism (8), a portion of the light is transmitted to the reflector through the glass plate (9). (10), and after being reflected by the reflector (10), returns to the splitting surface of the second splitting prism (8), forming reference light; another part of the light irradiates the silicon-based liquid crystal box (20), and is reflected by the top surface of the silicon base plate (13) or the bottom surface of the cover glass (11) to the splitting surface of the second splitting prism (8), forming test light; the reference light and the test light interfere with each other at the splitting surface of the second splitting prism (8), and the interference light is projected to the first splitting prism (4) of the imaging system (401) through the Michelson interference objective lens (19).

2. The LCoS liquid crystal box thickness global detection device based on low-coherence light Michelson interference according to claim 1, characterized in that: A plurality of spacers (12) are arranged on the top surface of the silicon substrate (13), a void layer is formed between the plurality of spacers (12), and the cover glass (11) is correspondingly placed on top of the plurality of spacers (12).

3. The LCoS liquid crystal box thickness global detection device based on low-coherence light Michelson interference according to claim 1, characterized in that: The glass plate (9) and the cover glass (11) have the same thickness and are made of the same material.

4. The LCoS liquid crystal cell thickness global detection device based on low-coherence light Michelson interference according to claim 1, characterized in that: The nanopositioning platform (14) comprises a slide (21) and a base plate (22), wherein the slide (21) is configured as a piezoelectric ceramic, and the slide (21) is connected to a computer (17) via a controller, the slide (21) is located on the top of the base plate (22), a slide groove is provided on the top surface of the base plate (22), and a slide rail (23) is installed inside the slide groove via screws, a slide bar (24) is provided on the bottom surface of the slide (21), and the slide bar (24) is located inside the slide groove, the silicon-based liquid crystal box (20) is fixedly installed on the top surface of the slide (21) via a mounting component, the base plate (22) is connected to the computer (17) via a controller, and when the controller is in operation, the slide (21) slides inside the slide groove of the base plate (22) via the slide bar (24), and the sliding slide (21) drives the silicon-based liquid crystal box (20) to move horizontally synchronously via the mounting component.

5. The LCoS liquid crystal cell thickness global detection device based on low-coherence light Michelson interference according to claim 4, characterized in that: The mounting component comprises two groups of opposing clamping frames, the two groups of clamping frames are respectively located on both sides of the silicon base plate (13), the clamping frames comprise two opposing side frames (25), a cross bar (26) is fixed to one side of the side frame (25), and the cross bars (26) of the two side frames (25) are matched with each other, a rotating sleeve (27) is spirally sleeved on the surface of the cross bar (26), and the two ends of the rotating sleeve (27) are respectively sleeved on the ends of the two cross bars (26), and the rotating sleeve (27) causes the two cross bars (26) to move closer to or farther away from each other.

6. The LCoS liquid crystal cell thickness global detection device based on low-coherence light Michelson interference according to claim 5, characterized in that: A side plate (28) is provided on the other side of the side frame (25), the inner side of the side plate (28) corresponds to the side edge of the silicon substrate (13), the inner side of the side plate (28) is fixed with an insertion rod (29) inserted into the inside of the side frame (25), the outer side of the side frame (25) is provided with two side grooves, a slider (30) is provided inside the side groove, and the slider (30) is fixedly connected to the insertion rod (29), the movable side plate (28) drives the slider (30) to move inside the side groove by means of the insertion rod (29), a clamping groove is provided on one side of the side groove, and the slider (30) corresponds to the clamping groove.

7. The LCoS liquid crystal cell thickness global detection device based on low-coherence light Michelson interference according to claim 6, characterized in that: Two pressing plates (31) are arranged on the top of the side frame (25), and a pressing block (32) is arranged on the bottom surface of the inner end of the pressing plate (31). The pressing plate (31) is pressed on the top surface of the silicon substrate (13) by the pressing block (32). A vertical rod (33) penetrating the top of the side groove is fixed to the outer end of the pressing plate (31), and a wedge block (34) is fixed to the bottom end of the vertical rod (33). The wedge block (34) corresponds to the slider (30). The surface of the vertical rod (33) is sleeved on the spring (35). The bottom end of the spring (35) is connected to the top surface of the wedge block (34), and the top end of the spring (35) is connected to the inner top of the side groove. The bottom surface of the wedge block (34) and the top surface of the slider (30) are both inclined. The slider (30) moving into the slot gradually moves away from the wedge block (34). The elastic force of the spring (35) causes the wedge block (34) to move downward inside the side groove.

8. The LCoS liquid crystal cell thickness global detection device based on low-coherence light Michelson interference according to claim 7, characterized in that: The two wedge blocks (34) are fixedly connected by a connecting plate, a screw rod (36) passes through the center of the connecting plate, and the bottom end of the screw rod (36) is spirally inserted into the top surface of the slide table (21).

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