Focal length measuring device and measuring method

Abstract

The invention discloses a focal length measuring device and measuring method.The measuring device comprises a light source module, an adjusting module and a measuring module, the light source module comprises a light source assembly and a support assembly, the light source assembly comprises at least two parallel light pipes with different focal lengths, and the parallel light pipes are arranged on the support assembly side by side; the optical axes of the collimators are parallel and the central heights are consistent; the adjusting module comprises a first adjusting assembly and a second adjusting assembly, the first adjusting assembly and the second adjusting assembly are sequentially arranged in the emission direction of a light path emitted by one collimator, and the first adjusting assembly is used for installing a to-be-measured lens and adjusting the position of the to-be-measured lens; the measuring module is installed on the second adjusting assembly, and the position of the measuring module is adjusted through the second adjusting assembly so that the measuring module, the to-be-measured lens and the collimator can be coaxial and clearly imaged.

Description

Technical Field

[0001] The present invention relates to the field of photoelectric detection technology, and in particular to a focal length measuring device and a measuring method. Background Art

[0002] Optical lenses are essential components in optical imaging systems, and their focal length is a crucial parameter. The length of a lens's focal length determines the size of the focal plane image, the angle of view, and the depth of field. Therefore, the accuracy of the focal length directly impacts the imaging quality of the entire optical system, necessitating high-precision measurement of the lens' effective focal length.

[0003] The magnification method is commonly used to measure the focal length of a lens or optical system. To minimize measurement errors, the focal length of the collimator is typically set to 2 to 5 times the focal length of the lens being measured. If the collimator's focal length does not meet this requirement, the collimator must be replaced, otherwise measurement errors will increase. However, frequent collimator replacement complicates measurement operations, leading to lower measurement efficiency. Summary of the Invention

[0004] In response to the above-mentioned deficiencies in the prior art, the present invention provides a focal length measurement device and a measurement method, which can solve the technical problem in the prior art that the operation process is cumbersome due to the need to replace the corresponding parallel light tube to ensure measurement accuracy, thereby leading to low measurement efficiency.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a focal length measuring device, comprising: A light source module includes a light source assembly and a bracket assembly, wherein the light source assembly includes at least two collimators with different focal lengths, and the plurality of collimators are arranged side by side on the bracket assembly, with the optical axes of the collimators being parallel and the center heights being consistent; An adjustment module, comprising a first adjustment component and a second adjustment component, wherein the first adjustment component and the second adjustment component are arranged in sequence along the emission direction of the light path emitted by one of the collimators, and the first adjustment component is used to install a lens to be tested and adjust the position of the lens to be tested; The measuring module is mounted on the second adjusting assembly. The position of the measuring module is adjusted by the second adjusting assembly so that the measuring module, the lens to be measured and the parallel light tube are coaxial and form a clear image.

[0006] In some embodiments, the adjustment module further includes a third adjustment component, which is disposed at the bottom of the bracket assembly and is used to adjust the position of the bracket assembly so that the light paths emitted by parallel light tubes of different focal lengths are respectively aligned with the lens to be measured and the measurement module.

[0007] In some embodiments, the light source assembly includes a first parallel light tube, a second parallel light tube, a third parallel light tube and a fourth parallel light tube, the bracket assembly includes a support seat, a first clamp, a second clamp, a third clamp and a mirror seat, the bottoms of the two support seats are fixed on the third adjustment assembly, the first parallel light tube is installed on the tops of the two support seats, the first clamp is sleeved on one end of the first parallel light tube, the mirror seat is connected to one side of the first clamp, the second parallel light tube and the third parallel light tube are installed in the two inner cavities of the mirror seat, the second clamp is connected to the other side of the first clamp, the third clamp is connected to one side of the support seat, and the fourth parallel light tube is installed in the second clamp and the third clamp.

[0008] In some embodiments, the first adjustment assembly includes a first clamp, a carrier plate, a rotating table, a pitching table, a first translation table, a first lifting table, and a base plate. The first clamp is used to mount the lens to be tested. The first clamp is fixed to the carrier plate. The rotating table, the pitching table, the first translation table, the first lifting table, and the base plate are sequentially arranged at the bottom of the carrier plate to adjust the position of the first clamp through the carrier plate.

[0009] In some embodiments, the second adjustment assembly includes a second clamper, a second translation stage, a second lifting stage, a first slide and a first guide rail. The second clamper is used to install the measuring module. The second translation stage, the second lifting stage and the first slide are fixed in sequence at the bottom of the second clamper. The bottom of the first slide is slidably connected to the first guide rail.

[0010] In some embodiments, the third adjustment component includes a second slide and a second guide rail, the second slide is disposed at the bottom of the two support seats, and the second slide is slidably connected to the second guide rail.

[0011] In some embodiments, a control module is further included, and the control module is electrically connected to the light source component, the first adjustment component, the second adjustment component, the third adjustment component and the measurement module respectively.

[0012] In a second aspect, the present invention further provides a focal length measurement method, which is implemented based on the focal length measurement device provided in the first aspect of the present invention and includes the following steps: Mounting the lens to be tested on the first adjustment assembly and adjusting it to be coaxial with the corresponding collimator; The position of the measuring module is adjusted by the second adjusting component so that the measuring module is coaxial with the lens to be measured and forms a clear image; The focal length of the lens to be measured is measured by a measuring module.

[0013] In some embodiments, the measurement method further includes selecting a collimator with a corresponding focal length according to the focal length of the lens to be measured, and adjusting the position of the collimator by a third adjustment component so that it is coaxial with the lens to be measured.

[0014] In some embodiments, the measurement method further includes adjusting the brightness of the light source of the parallel light tube through a control module, controlling the position adjustment of the first adjustment component, the second adjustment component and the third adjustment component respectively through the control module, and calculating the focal length of the lens to be measured through the control module.

[0015] Compared with the prior art, the beneficial effects of the present invention mainly include: The focal length measurement device provided by the present invention has a light source assembly including at least two collimators with different focal lengths. Therefore, when the focal length of the lens to be measured changes, the lens to be measured and the measurement module only need to be moved coaxially with the collimator of the corresponding focal length using the first adjustment assembly and the second adjustment assembly to ensure measurement accuracy without the need for frequent replacement of the collimators. Therefore, the present invention is simple to operate and can improve the efficiency of focal length measurement. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of the measuring device of the present invention; Figure 2 This is a schematic diagram of the overall structure of the light source module of the present invention; Figure 3 yes Figure 2 A top view of Figure 4 is a front view of the first adjustment assembly of the present invention; Figure 5 is a side view of the first adjustment assembly of the present invention; Figure 6 is a front view of the second adjustment assembly of the present invention; Figure 7 is a side view of the second adjustment assembly of the present invention; Figure 8 is a side view of the third adjustment assembly of the present invention; Figure 9 is a top view of the third adjustment assembly of the present invention; Figure 10 4 is a flow chart of the measurement method of the present invention.

[0017] Description of reference numerals: 100, light source module, 110, light source assembly, 111, first collimator, 112, second collimator, 113, third collimator, 114, fourth collimator, 120, bracket assembly, 121, support base, 122, first clamp, 123, second clamp, 124, third clamp, 125 mirror base; 200, adjustment module, 210, first adjustment assembly, 211, first clamper, 212, loading stage, 213, rotation stage, 214, pitch stage, 215, first translation stage, 216, first lifting stage, 217, bottom plate, 218, connecting block, 220, second adjustment assembly, 221, second clamper, 222, second translation stage, 223, second lifting stage, 224, first slide, 225, first guide rail, 230, third adjustment assembly, 231, second slide, 232, second guide rail; 300. Measurement module. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0019] In existing lens focal length measurement, to ensure measurement accuracy, the collimator focal length is typically 2 to 5 times that of the lens being measured. Therefore, for lenses of different focal lengths, collimators of corresponding focal lengths must be replaced. Furthermore, the newly replaced light source must be readjusted to the optical axis coaxiality of the measurement component and the lens being measured. This results in cumbersome operation and low measurement efficiency. To address this technical issue, the present invention provides a focal length device and measurement method that can efficiently and quickly measure the focal length of a lens.

[0020] On the one hand, if Figure 1 As shown, the present invention provides a focal length measuring device, which includes a light source module 100 , an adjustment module 200 and a measurement module 300 .

[0021] In which, the light source module 100 includes a light source assembly 110 and a bracket assembly 120, the light source assembly 110 includes at least two collimators with different focal lengths, and multiple collimators are arranged side by side on the bracket assembly 120, and the optical axes of each collimator are parallel and the center heights are consistent; the adjustment module 200 includes a first adjustment assembly 210 and a second adjustment assembly 220, and the first adjustment assembly 210 and the second adjustment assembly 220 are arranged in sequence along the emission direction of the light path emitted by one of the collimators, and the first adjustment assembly 210 is used to install the lens to be measured and adjust the position of the lens to be measured; the measuring module 300 is installed on the second adjustment assembly 220, and the position of the measuring module 300 is adjusted by the second adjustment assembly 220 so that the measuring module 300, the lens to be measured and the collimator are coaxial and clearly imaged.

[0022] The focal length measurement device provided by the present invention has a light source assembly 110 including at least two collimators with different focal lengths. For lenses with different focal lengths, it is only necessary to adjust the corresponding collimators to be coaxial with the optical axes of the lens to be measured and the measurement module 300 through the first adjustment assembly 210 and the second adjustment assembly 220 without replacing the light source, thereby reducing the number of operating steps. Therefore, the present invention can significantly improve measurement efficiency.

[0023] In one embodiment, in order to better and more conveniently adjust the coaxiality among the collimator, the lens to be measured and the measuring module 300, the adjustment module 200 further includes a third adjustment component 230. The third adjustment component 230 is disposed at the bottom of the bracket assembly 120 and is used to adjust the position of the bracket assembly 120 so that the light paths emitted by the collimators with different focal lengths are respectively aligned with the lens to be measured and the measuring module 300.

[0024] In one embodiment, Figure 2 and Figure 3As shown, the light source assembly 110 includes a first collimator 111, a second collimator 112, a third collimator 113 and a fourth collimator 114; the bracket assembly 120 includes a support seat 121, a first clamp 122, a second clamp 123, a third clamp 124 and a mirror seat 125, the bottoms of the two support seats 121 are fixed to the third adjustment assembly 230, the first collimator 111 is installed on the tops of the two support seats 121, the first clamp 122 is sleeved on one end of the first collimator 111, the mirror seat 125 is connected to one side of the first clamp 122, the second collimator 112 and the third collimator 113 are installed in the two inner cavities of the mirror seat 125, the second clamp 123 is connected to the other side of the first clamp 122, the third clamp 124 is connected to one side of the support seat 121, and the fourth collimator 114 is installed in the second clamp 123 and the third clamp 124.

[0025] In this embodiment, since the light source assembly 110 includes four collimators with different focal lengths, and the optical axes of these collimators are parallel to each other and the center heights are consistent, the bracket assembly 120 can be moved by the third adjustment assembly 230, so that the collimators with different focal lengths are respectively aligned with the lens to be measured and the measurement module 300. Therefore, there is no need to re-adjust the optical axis, which avoids the problem of frequent replacement of collimators and cumbersome operations.

[0026] In this embodiment, the models of the first collimator 111, the second collimator 112, the third collimator 113, and the fourth collimator 114 are F1000, F120, F50, and F200, respectively. The first collimator 111 is fastened to the through holes of the two support seats 121 by M6 screws as a reference; the second collimator 112 and the third collimator 113 are fastened to the two inner cavities of the lens seat 125 by M3 screws, and the fourth collimator 114 is fastened to the second clamp 123 and the third clamp 124 by M4 screws. The positions of the first collimator 111, the second collimator 112, the third collimator 113, and the fourth collimator 114 can be adjusted by screws respectively, and finally adjusted to be parallel to each other and have the same center height.

[0027] In this embodiment, since the parameters of the first collimator 111 are: focal length f=1000 mm, aperture D=Φ100 mm, the parameters of the second collimator 112 are: focal length f=120 mm, aperture D=Φ30 mm, the parameters of the third collimator 113 are: f=50 mm, aperture D=Φ12 mm, and the parameters of the fourth collimator 114 are: f=200 mm, aperture D=Φ50 mm; therefore, the focal length measurement device provided by the present invention can realize rapid measurement of lenses with a focal length range of 10 mm to 500 mm, and the maximum test aperture can reach Φ100 mm, which basically covers commonly used lens models. Therefore, the measurement device provided by the present invention also broadens the lens measurement range.

[0028] In one embodiment, Figure 4 and Figure 5 As shown, the first adjustment assembly 210 includes a first clamper 211, a stage 212, a rotating stage 213, a pitching stage 214, a first translation stage 215, a first lifting stage 216 and a base plate 217. The first clamper 211 is used to mount the lens to be tested. The first clamper 211 is fixed on the stage 212. The rotating stage 213, the pitching stage 214, the first translation stage 215, the first lifting stage 216 and the base plate 217 are sequentially connected to the bottom of the stage 212 by M6 screws. In this way, the lens to be tested can be adjusted in the Y-axis direction through the first lifting stage 216, the lens to be tested can be adjusted in the X-axis direction through the first translation stage 215, the lens to be tested can be adjusted in the Z-axis direction through the pitching stage 214, and the lens to be tested can be rotated 360° through the rotating stage 213, thereby finally achieving position adjustment of the lens to be tested in four dimensions.

[0029] In one embodiment, the first adjustment assembly 210 further includes a connecting block 218 . The connecting block 218 is fixed on the stage 212 , and the first clamper 211 is fixed on the connecting block 218 .

[0030] It is understandable that after the connecting block 218 and the first clamp 211 are detached from the stage 212 , other optical systems and optical lens components can still be fixed on the stage 212 .

[0031] In one embodiment, Figure 6 and Figure 7As shown, the second adjustment assembly 220 includes a second clamper 221, a second translation platform 222, a second lifting platform 223, a first slide 224 and a first guide rail 225. The second clamper 221 is used to install the measuring module 300. The second translation platform 222, the second lifting platform 223 and the first slide 224 are fixed on the bottom of the second clamper 221 in sequence. The bottom of the first slide 224 is slidably connected to the first guide rail 225. In this way, the measurement module 300 can be moved in the X-axis direction by moving the first slide 224 on the first guide rail 225, the measurement module 300 can be moved in the Y-axis direction by the second lifting platform 223, and the measurement module 300 can be moved in the Z-axis direction by the second translation platform 222, thereby finally realizing the position adjustment of the measurement module 300 in three dimensions.

[0032] In one embodiment, Figure 8 and Figure 9 As shown, the third adjustment component 230 includes a second slide 231 and a second guide rail 232. The second slide 231 is arranged at the bottom of the two support seats 121, and the second slide 231 is slidably connected to the second guide rail 232. In this way, the support seat 121 can be driven to move horizontally, thereby realizing the movement of the parallel light tube, so as to facilitate the selection of the corresponding parallel light tube.

[0033] It is understandable that the first translation stage 215 , the second translation stage 222 , the first slide 224 and the second slide 231 are one-dimensional electrically controlled platforms, and the lengths of the first guide rail 225 and the second guide rail 232 can be flexibly set according to actual adjustment needs.

[0034] In one embodiment, the measurement module 300 is an electronic video microscope.

[0035] In one embodiment, the measuring device also includes a control module, which is electrically connected to the light source assembly 110, the first adjustment assembly 210, the second adjustment assembly 220, the third adjustment assembly 230 and the measuring module 300, respectively, and specifically electrically connected to each parallel light tube, the rotating table 213, the pitch table 214, the first translation table 215, the first lifting table 216, the second translation table 222, the second lifting table 223, the first slide 224, the second slide 231 and the measuring module 300.

[0036] In this embodiment, the control module can be used to adjust the light source size and brightness of each collimator according to the size of the lens aperture to be measured. The control module controls the rotating stage 213, the pitch stage 214, the first translation stage 215, the first lifting stage 216, the second translation stage 222, the second lifting stage 223, the first slide 224, and the second slide 231 to adjust the coaxiality of the collimator, the lens to be measured, and the measurement module 300. The control module controls the measurement module 300 to perform data acquisition and video output, and performs data processing on the focal plane pattern of the product to be measured, calculates the focal length value, and enters the data.

[0037] On the other hand, Figure 10 As shown, the present invention provides a focal length measurement method, which is implemented according to the focal length measurement device provided above, and specifically includes the following steps: Step S1, mounting the lens to be tested on the first adjustment assembly 210 and adjusting it to be coaxial with the corresponding collimator; Step S2, adjusting the position of the measuring module 300 by the second adjusting component 220 so that it is coaxial with the lens to be measured and forms a clear image; Step S3: measuring the focal length of the lens to be measured by the measuring module 300.

[0038] In one embodiment, step S2 includes: Step S21, adjusting the measuring module 300 to be coaxial with the lens to be measured and the collimator by the second translation stage 222 and the second lifting stage 223; In step S22 , the first slide 224 is moved on the first guide rail 225 to search for an image of the measurement module 300 . When an image is found, the control module controls the first slide 224 to move until a clear image is found.

[0039] In one embodiment, a collimator with a corresponding focal length is selected according to the focal length of the lens to be measured, and the position of the collimator is adjusted by a third adjustment component 230 so that it is coaxial with the lens to be measured.

[0040] In one embodiment, the control module is further used to adjust the brightness of the light source of the collimator, to control the position adjustment of the first adjustment component 210, the second adjustment component 220 and the third adjustment component 230 respectively, and to calculate the focal length of the lens to be tested by the control module.

[0041] In summary, the focal length measurement device and measurement method provided by the present invention can realize the measurement of the focal length of the lens within a wide focal length range, avoiding the problems of frequent replacement of parallel light tubes, cumbersome operations, and re-adjustment of the optical axis, and can greatly improve the measurement efficiency of the lens focal length.

[0042] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A focal length measuring device, characterized in that: include: A light source module includes a light source assembly and a bracket assembly, wherein the light source assembly includes at least two collimators with different focal lengths, and the plurality of collimators are arranged side by side on the bracket assembly, with the optical axes of the collimators being parallel and the center heights being consistent; An adjustment module, comprising a first adjustment component and a second adjustment component, wherein the first adjustment component and the second adjustment component are arranged in sequence along the emission direction of the light path emitted by one of the collimators, and the first adjustment component is used to install a lens to be tested and adjust the position of the lens to be tested; The measuring module is mounted on the second adjusting assembly. The position of the measuring module is adjusted by the second adjusting assembly so that the measuring module, the lens to be measured and the parallel light tube are coaxial and form a clear image.

2. The focal length measuring device according to claim 1, wherein: The adjustment module further includes a third adjustment component, which is disposed at the bottom of the bracket component and is used to adjust the position of the bracket component so that the light paths emitted by the collimators with different focal lengths are respectively aligned with the lens to be measured and the measurement module.

3. The focal length measuring device according to claim 2, wherein: The light source assembly includes a first collimator, a second collimator, a third collimator and a fourth collimator; the bracket assembly includes a support seat, a first clamp, a second clamp, a third clamp and a mirror seat; the bottoms of the two support seats are fixed to the third adjustment assembly; the first collimator is installed on the tops of the two support seats; the first clamp is sleeved on one end of the first collimator; the mirror seat is connected to one side of the first clamp; the second and third collimators are installed in the two inner cavities of the mirror seat; the second clamp is connected to the other side of the first clamp; the third clamp is connected to one side of the support seat; the fourth collimator is installed in the second clamp and the third clamp.

4. The focal length measuring device according to claim 1, wherein: The first adjustment assembly includes a first clamp, a carrier plate, a rotating table, a pitching table, a first translation table, a first lifting table and a base plate. The first clamp is used to mount the lens to be tested. The first clamp is fixed to the carrier plate. The rotating table, the pitching table, the first translation table, the first lifting table and the base plate are sequentially arranged at the bottom of the carrier plate to adjust the position of the first clamp through the carrier plate.

5. The focal length measuring device according to claim 1, wherein: The second adjustment assembly includes a second clamper, a second translation platform, a second lifting platform, a first slide and a first guide rail. The second clamper is used to install the measuring module. The second translation platform, the second lifting platform and the first slide are fixed in sequence at the bottom of the second clamper. The bottom of the first slide is slidably connected to the first guide rail.

6. The focal length measuring device according to claim 3, wherein: The third adjustment component includes a second slide and a second guide rail. The second slide is arranged at the bottom of the two support seats, and the second slide is slidably connected to the second guide rail.

7. The focal length measuring device according to claim 2, wherein: It also includes a control module, which is electrically connected to the light source component, the first adjustment component, the second adjustment component, the third adjustment component and the measurement module respectively.

8. A focal length measurement method, implemented based on the focal length measurement device according to any one of claims 1 to 7, characterized in that: The following steps are involved: Mounting the lens to be tested on the first adjustment assembly and adjusting it to be coaxial with the corresponding collimator; The position of the measuring module is adjusted by the second adjusting component so that the measuring module is coaxial with the lens to be measured and forms a clear image; The focal length of the lens to be measured is measured by a measuring module.

9. The focal length measurement method according to claim 8, wherein: The method further includes selecting a collimator with a corresponding focal length according to the focal length of the lens to be measured, and adjusting the position of the collimator through a third adjustment component so that the collimator is coaxial with the lens to be measured.

10. The focal length measurement method according to claim 9, wherein: It also includes adjusting the brightness of the light source of the parallel light tube through a control module, controlling the position adjustment of the first adjustment component, the second adjustment component and the third adjustment component respectively through the control module, and calculating the focal length of the lens to be tested through the control module.

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