Device and method for detecting the optical axis pointing of a focusing light source emission optical system

Abstract

This invention proposes a device and method for detecting the optical axis pointing of a focusing light source emitting optical system, enabling high-precision measurement of the optical axis pointing of the focusing light source emitting optical system during the focusing process. This invention utilizes a long-distance linear motion platform and a spot position detection device to record the convergence position of the emitted light from the focusing light source emitting system at different spatial locations, calculates the change in the optical axis pointing of the system during focusing, and measures the position change of the spot over a long distance by directly receiving the emitted light spot from the focusing optical system, thus solving the problem of high-precision measurement of the optical axis pointing of the focusing light source emitting optical system during the focusing process.

Description

Technical Field

[0001] This invention relates to the field of optical axis pointing detection technology, and specifically to an optical axis pointing detection device and method for a focusing light source emitting optical system. Background Technology

[0002] In the field of laser precision measurement, focusing laser emitting optical systems are increasingly used. By focusing, the emitted laser can be accurately focused onto the surface of the object being measured, improving light energy utilization and spatial resolution. However, due to errors in the manufacturing and assembly of the focusing mechanism, the optical axis direction of the emitted laser will change during the focusing process. This will lead to inaccurate measurement results. For example, in precision laser ranging, if the optical axis of the emitted laser changes, the actual measurement direction will change, resulting in inaccurate measurements. Therefore, it is necessary to measure the change in the direction of the optical axis during the focusing process of the optical system.

[0003] Existing devices for detecting changes in the optical axis pointing of a focusing light source emission optical system include: detector tubes, internal focusing telescopes, and detection devices based on position-sensitive elements such as PSDs and four-quadrant detectors.

[0004] The detector tube can establish a series of virtual images ranging from near distance to infinity, equivalent to coaxial targets. The focusing light source emitting optical system being tested images these targets by focusing, and the optical axis orientation of the focusing light source emitting optical system is determined from the images. This method can only detect the optical axis orientation of focusing light source emitting optical systems used for imaging, and is not suitable for optical axis detection of focusing laser emitting optical systems.

[0005] Internal focusing telescopes have their own focusing function, allowing them to receive beams emitted by focusing laser-emitting optical systems and converge them onto an internal reticle. If the optical system under test experiences a change in optical axis orientation, the lateral displacement of the beam spot can be measured on the reticle of the internal focusing telescope. The problem with this method is that the internal focusing telescope also requires focusing during measurement, and its own optical axis changes during this process, typically by 4″ to 10″, which does not meet the requirements for high-precision optical axis pointing accuracy detection.

[0006] Detection devices based on position-sensitive elements such as PSDs and four-quadrant detectors can receive lasers emitted by a focusing light source's optical system and analyze the position of the intersection between the emitted light's optical axis and the detector. However, in this method, the effective area of ​​the sensor is usually small. As the optical system under test focuses, the light spot illuminating the detector surface will increase. When the light spot exceeds the detector's sensitive surface, it becomes unusable. Summary of the Invention

[0007] In view of this, the present invention proposes a device and method for detecting the optical axis pointing of a focusing light source emitting optical system, which can realize high-precision measurement of the optical axis pointing of the focusing light source emitting optical system during the focusing process.

[0008] To achieve the above objectives, the technical solution of the present invention is as follows:

[0009] This invention discloses a device for detecting the optical axis pointing of a focusing light source emitting optical system, comprising a linear motion platform, a spot position detection unit, and an indicator laser. The linear motion platform includes a base, a motion unit, and a position measuring device, which measures the movement distance of the motion unit. The spot position detection unit includes two spot position detectors mounted on the same base; one records the change in the spot position of the focusing light source emitting optical system, and the other records the light emitted by the indicator laser. The indicator laser emits collimated visible light as a direction reference. In the initial measurement state, the spot position detection unit is fixed on the motion unit, and the photosensitive surfaces of the two detectors are perpendicular to the motion axis. The indicator laser and the optical system under test are placed on the extension of the motion axis of the linear motion platform, separated from the linear motion platform, and the motion unit moves to the point closest to the optical system under test. The optical system under test is the focusing light source emitting optical system.

[0010] The focusing light source emitting optical system uses laser light as its light source.

[0011] The position measuring device is either a grating ruler or a laser interferometer.

[0012] The detector is an image or spot position sensitive element.

[0013] The present invention also provides a method for detecting the optical axis pointing of a focusing light source emitting optical system, which uses the device described in the present invention to achieve the detection, and includes the following steps:

[0014] Step 1: Adjust the detection device to the initial measurement state, and set the position of the motion unit to point 0 at this time;

[0015] Step 2: Adjust the indicator laser so that the indicator laser is incident on the center of the detector corresponding to the indicator laser, and make the optical axis of the indicator laser parallel to the motion axis of the linear motion platform; focus the optical system under test so that the emitted light spot converges on the center of the detector that detects the position change of the light spot of the optical system under test, and make the optical axis of the optical system under test parallel to the motion axis of the linear motion platform.

[0016] Step 3: Using the motion axis of the linear motion platform as the Z-axis and the centers O1 and O2 of the two detectors as vertices, establish the O1-XYZ rectangular coordinate system and the O2-XYZ rectangular coordinate system respectively; using the current position as the reference point, record the position (x11, y11) of the light spot center of the focusing light source emitting optical system on the corresponding detector, and record the position (x21, y21) of the light spot center of the indicator laser on the corresponding detector.

[0017] Step 4: Move the motion unit to move the spot position detection unit a certain distance. L The focusing process converges the light emitted by the optical system under test onto a detector that detects changes in the position of the light spot on the optical system under test. The center position (x) of the light spot on the detector at this moment is recorded. 12 ,y 12 ), and the center position of the light spot of another detector (x) 22 ,y 22 );

[0018] Step 5: Calculate the change in the optical axis direction after focusing. The distance Δ of the emitted light spot from the focusing light source emitting optical system. d for: .

[0019] Beneficial effects:

[0020] 1. The device of this invention includes a linear motion platform, a spot position detection unit, and an indicator laser. The linear motion platform includes a base and a motion unit, and is equipped with a device capable of measuring the position, enabling precise measurement of the motion distance of the motion unit. The spot position detection unit includes two spot position detectors mounted on the same base, reflecting the nonlinearity of the linear motion translation stage. The indicator laser emits collimated visible light as a directional reference, and by directly receiving the spot emitted from the focusing light source emitting optical system, it measures the position change of the spot over a long distance, solving the problem of high-precision measurement of the optical axis orientation of the focusing light source emitting optical system during the focusing process.

[0021] 2. The method of the present invention utilizes a long-distance linear motion platform and a light spot position detection device to record the convergence position of the light emitted by the focusing light source emitting optical system at different spatial positions, calculate the change in the direction of the optical axis of the system during focusing, and measure the position change of the light spot over a long distance by directly receiving the light spot emitted by the focusing light source emitting optical system. This solves the problem of high-precision measurement of the optical axis direction of the focusing light source emitting optical system during focusing.

[0022] 3. Based on the principle of rectilinear propagation of light, this invention focuses the light beam at two positions a distance L apart. The distance Δd that the light spot moves perpendicular to the beam propagation direction at these two positions is measured, thereby calculating the change in the optical axis direction after focusing. This invention is applicable to optical axis detection in all focusing-type light source emitting optical systems. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the detection device of the present invention.

[0024] Figure 2 This is a schematic diagram of the spot position detection unit in this invention. Detailed Implementation

[0025] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0026] A focusing light source emitting optical system can concentrate a light beam at different distances. Based on the principle of rectilinear propagation of light, for distances of... L Focus at two positions to converge the beam. If the distance can be measured... L At the two positions, the light spot moves a distance Δ perpendicular to the direction of beam propagation. d Then the change in the optical axis direction after focusing can be calculated:

[0027]

[0028] Based on the above principle, this invention overcomes the shortcomings of existing technologies in detecting the optical axis pointing of a focusing light source emitting optical system. It utilizes a long-distance linear motion platform and a spot position detection device to record the convergence position of the emitted light from the focusing light source emitting optical system at different spatial positions, calculates the change in the optical axis pointing of the system during focusing, and uses this information to detect the optical axis of the focusing light source emitting optical system, measuring the actual change in the optical axis pointing of the optical system during focusing.

[0029] The optical axis pointing detection device of the focusing light source emitting optical system of the present invention is as follows: Figure 1 As shown, the detection device of the present invention includes a linear motion platform, a spot position detection unit, and an indicator laser. The linear motion platform includes a base, a motion unit, and a position measuring device, such as a grating ruler or a laser interferometer, for accurately measuring the motion distance of the motion unit. The spot position detection unit includes two spot position detectors (detector 1 and detector 2) mounted on the same base. Detector 1 records the spot position change of the focusing light source emitting optical system, and detector 2 records the light emitted by the indicator laser, reflecting the nonlinearity of the linear motion translation stage. Specifically, detector 1 and detector 2 can be implemented using image or spot position sensitive elements. The spot position detection unit is as follows: Figure 2As shown; the indicator laser emits collimated visible light as a direction reference. In the initial measurement state, the spot position detection unit is fixed on the motion unit, and the photosensitive surfaces of the two detectors are perpendicular to the motion axis; the indicator laser and the optical system under test are placed on the extension line of the motion axis of the linear motion platform, separated from the linear motion platform, and the motion unit moves to the point closest to the optical system under test.

[0030] Furthermore, for a focusing light source emitting optical system that uses laser as a light source, namely a focusing laser emitting optical system, the detection device of the present invention can achieve accurate detection.

[0031] This invention also proposes a method for detecting the optical axis pointing of a focusing light source emitting optical system. The detection device of this invention is used, and the specific implementation steps are as follows:

[0032] Step 1: Adjust the detection device to the initial measurement state, and set the position of the motion unit to point 0 at this time;

[0033] Step 2: Adjust the indicator laser so that the indicator laser is incident on the center of detector 2, and make the optical axis of the indicator laser parallel to the motion axis of the linear motion platform; focus the optical system under test so that the emitted light spot converges on the center of detector 1, and make the optical axis of the optical system under test parallel to the motion axis of the linear motion platform.

[0034] Step 3: Using the motion axis of the linear motion platform as the Z-axis, and the centers O1 and O2 of detectors 1 and 2 as vertices, establish the O1-XYZ rectangular coordinate system and the O2-XYZ rectangular coordinate system respectively. Using the current position as the reference point, record the position (x11, y11) of the light spot center of the focusing light source emitting optical system on detector 1, and record the position (x21, y21) of the light spot center of the indicator laser on detector 2.

[0035] Step 4: Move the motion unit to move the spot position detection unit a certain distance. L The focusing process concentrates the light emitted by the optical system under test onto detector 1, and the center position (x) of the light spot on detector 1 is recorded at this time. 12 ,y 12 The center position of the light spot of detector 2 (x) 22 ,y 22 ).

[0036] Step 5: Calculate the change in the optical axis direction after focusing. The distance Δ of the emitted light spot from the focusing light source emitting optical system. d for:

[0037]

[0038] In summary, this invention solves the problem of high-precision measurement of the optical axis orientation of a focusing light source emitting optical system during focusing by directly receiving the light spot emitted from the focusing light source emitting optical system and measuring the positional change of the light spot over a long distance.

[0039] In summary, the above are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A device for detecting the optical axis pointing of a focusing light source emitting optical system, characterized in that, The system includes a linear motion platform, a spot position detection unit, and an indicator laser. The linear motion platform comprises a base, a motion unit, and a position measuring device, which measures the movement distance of the motion unit. The spot position detection unit includes two spot position detectors mounted on the same base; one records the spot position change of the focusing optical system, and the other records the light emitted by the indicator laser. The indicator laser emits collimated visible light as a direction reference. In the initial measurement state, the spot position detection unit is fixed on the motion unit, and the photosensitive surfaces of the two detectors are perpendicular to the motion axis. The indicator laser and the optical system under test are placed on the extension of the motion axis of the linear motion platform, separated from the linear motion platform, and the motion unit moves to the point closest to the optical system under test. The focusing light source emitting optical system uses laser as the light source; The position measuring device is a grating ruler or a laser interferometer; the detector is an image or spot position sensitive element.

2. A method for detecting the optical axis pointing of a focusing light source emitting optical system, characterized in that, The detection is performed using the apparatus as described in claim 1, comprising the following steps: Step 1: Adjust the detection device to the initial measurement state, and set the position of the motion unit to point 0 at this time; Step 2: Adjust the indicator laser so that the indicator laser is incident on the center of the detector corresponding to the indicator laser, and make the optical axis of the indicator laser parallel to the motion axis of the linear motion platform; focus the optical system under test so that the emitted light spot converges on the center of the detector corresponding to the change in the light spot position of the optical system, and make the optical axis of the optical system under test parallel to the motion axis of the linear motion platform. Step 3: Using the motion axis of the linear motion platform as the Z-axis and the centers O1 and O2 of the two detectors as vertices, establish the O1-XYZ rectangular coordinate system and the O2-XYZ rectangular coordinate system respectively; using the current position as the reference point, record the position (x, y, z) of the light spot center of the focusing optical system on the corresponding detector. 11 y 11 Record the position (x) of the center of the laser spot on the corresponding detector. 21 y 21 ); Step 4: Move the motion unit to move the spot position detection unit a certain distance. L Focusing causes the light emitted by the optical system under test to converge onto the detector corresponding to the change in the position of the light spot on the optical system, and the center position of the light spot on the detector at this time is recorded (x). 12 ,y 12 ), and the center position of the light spot of another detector (x) 22 ,y 22 ); Step 5: Calculate the change in the optical axis direction after focusing. The distance Δ of the emitted light spot from the focusing optical system d for: .

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