System and method for detecting energy uniformity of focusing light spot of laser receiving lens

Abstract

The invention discloses a system and a method for detecting energy uniformity of a focusing light spot of a laser receiving lens, and belongs to the field of laser guidance. According to the invention, the adjustable diaphragm, the 1 * telescope system and the pupil connection and object image conjugation principle of the to-be-measured lens are utilized, and continuous adjustment of the clear aperture of the entrance pupil of the to-be-measured lens in any field of view can be realized in cooperation with the single-axis turntable; a relation curve of different focusing spot sizes and response voltage of the four-quadrant laser detector can be obtained, and a test curve of focusing spot uniformity in any view field can be obtained after data processing, so that detection of focusing spot energy uniformity of a laser receiving lens in any view field is realized.

Description

Technical Field

[0001] The invention belongs to the field of laser guidance, and in particular relates to a system and method for detecting energy uniformity of a focused light spot. Background Art

[0002] The laser receiving lens is a device that focuses the laser signal from the target onto the photosensitive surface of the four-quadrant laser detector. The uniformity of the energy of the focused light spot directly affects the linearity of the linear field of view characteristic curve in the semi-active laser guidance, and then affects the accuracy of the laser guidance. It can be seen that the uniformity of the energy of the focused light spot is an important quality indicator of the laser receiving lens.

[0003] In actual engineering applications, the linear field of view characteristic curve is compensated to linearity by testing the curve compensation. Errors will be introduced during the compensation process, thereby reducing the accuracy of laser guidance. By adjusting the energy uniformity of the focused spot of the laser receiving lens, the linear field of view characteristic curve can be directly made linear, which can eliminate the compensation error and improve the laser guidance performance. However, the current indicators of the energy uniformity of the focused spot mostly remain in the optical simulation stage, and there is a lack of effective detection methods for this indicator, that is, it is impossible to guide the adjustment and improvement of the uniformity of the focused spot of the laser receiving lens, thereby restricting the further improvement of the laser guidance performance. Summary of the invention

[0004] In view of this, the present invention provides a detection system and method for the uniformity of the energy of the focused light spot of a laser receiving lens, and provides a high-precision and high-efficiency method for realizing the adjustment of the laser receiving lens. The present invention utilizes the adjustable diaphragm, 1× telephoto system and pupil connection and object-image conjugation principle of the lens to be tested, and cooperates with a single-axis turntable to realize the continuous adjustment of the aperture of the incident pupil of the lens to be tested in any field of view. According to the corresponding relationship between the incident pupil of the lens to be tested and the size of the focused light spot on the image plane, the relationship curve between different focused light spot sizes and the response voltage (focused light spot energy) of the four-quadrant laser detector can be obtained. After data processing, the test curve of the uniformity of the focused light spot under any field of view can be obtained, thereby realizing the detection of the uniformity of the focused light spot energy in any field of view of the laser receiving lens.

[0005] The specific technical solutions are as follows:

[0006] A detection system for the energy uniformity of a focused light spot of a laser receiving lens comprises a laser simulator, an adjustable diaphragm, a 1× telescopic system, a lens to be tested, a four-quadrant detector and a single-axis turntable, wherein the centers of the photosensitive surfaces of the laser simulator, the adjustable diaphragm, the 1× telescopic system, the lens to be tested and the four-quadrant detector are arranged in sequence along the optical axis, the lens to be tested and the four-quadrant detector are placed on the single-axis turntable, and the center of the entrance pupil optical axis of the lens to be tested coincides with the rotation center of the turntable.

[0007] Furthermore, the adjustable aperture is placed at the entrance pupil position of the 1× telephoto system.

[0008] A method for detecting energy uniformity of a focused spot of a laser receiving lens, comprising: step 1, adjusting the relative positions on the axis of a 1× telephoto system and a lens to be tested so that an exit pupil of the former and an entrance pupil of the latter reach pupil connection;

[0009] Step 2, turn on the laser simulator, continuously adjust the effective aperture of the adjustable iris, obtain the relationship curve between the response voltage of the four-quadrant detector and the aperture of the adjustable iris, and use the corresponding relationship between the aperture and the focused spot area to convert the relationship curve between the response voltage and the focused spot size. After data processing, the focused spot uniformity curve can be obtained;

[0010] Step 3: Rotate the turntable to any angle ω within the lens field of view, radially move the four-quadrant detector photosensitive surface along the direction perpendicular to the optical axis, so that the center of the four-quadrant detector photosensitive surface coincides with the lens optical axis, repeat steps 1 to 2, and obtain the focus spot uniformity curve at any field of view angle ω.

[0011] Furthermore, in step 1, the 1× telescope system is a Keplerian telescope system with a magnification of 1 times.

[0012] Furthermore, the moving distance Δy of the photosensitive surface of the four-quadrant detector is determined by the formula:

[0013] Δy=f'·tanω

[0014] Where f' is the focal length of the lens to be tested.

[0015] Beneficial Effects

[0016] The method for detecting the energy uniformity of the focused light spot containing the 1× telescope system provided by the above technical solution has the following advantages:

[0017] 1. Based on the characteristic that the aperture of the continuously adjustable diaphragm can be adjusted steplessly, the present invention does not need to perform sampling point fitting, and can directly obtain a continuous test curve with high accuracy;

[0018] 2. The present invention utilizes the adjustable diaphragm, 1× telephoto system and pupil connection and object-image conjugation principle of the lens to be tested, and cooperates with a single-axis turntable to realize the uniformity detection of the focused light spot in any field of view of the laser receiving lens;

[0019] 3. The present invention adopts common devices in laser experiments such as laser simulators and four-quadrant laser detectors, which are simple to install and measure the optical path and easy to operate.

[0020] 4. The detection method of the energy uniformity of the focused light spot of the laser receiving lens of the present invention can provide guidance for the installation and adjustment of the laser receiving lens, and the linearity of the linear field of view characteristic curve can be achieved through the assembly of the laser lens. Compared with the existing linear field of view characteristic curve compensation method, the error caused by compensation can be eliminated, thereby further improving the laser guidance performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A schematic diagram of a detection system for the uniformity of energy of a focused light spot of a laser receiving lens according to the present invention;

[0022] In the figure: 1. Laser simulator; 2. Adjustable aperture; 3. 1× telescope system; 4. Lens to be tested; 4-1 Entrance pupil of lens to be tested; 5. Four-quadrant laser detector; 6. Single-axis turntable; 6-1. Rotation center of single-axis turntable DETAILED DESCRIPTION

[0023] In order to make the purpose, content and advantages of the present invention clearer, the specific implementation methods of the present invention are further described in detail below in conjunction with the drawings and embodiments.

[0024] like Figure 1 As shown, it is a schematic diagram of a detection system for the energy uniformity of a focused light spot of a laser receiving lens, which consists of a laser simulator 1, an adjustable aperture 2, a 1× telescope system 3, a lens to be tested 4, a four-quadrant detector 5 and a single-axis turntable 6.

[0025] Step 1: Arrange the centers of the photosensitive surfaces of the laser simulator 1, the adjustable aperture 2, the 1× telescopic system 3, the lens to be tested 4 and the four-quadrant detector 5 on the same optical axis in sequence, wherein the lens to be tested 4 and the four-quadrant detector 5 are placed on a single-axis turntable 6, and the entrance pupil 4-1 of the lens to be tested and the rotation center 6-1 of the single-axis turntable are placed so as to coincide with each other;

[0026] Step 2: Place a continuously adjustable diaphragm 2 at the entrance pupil position of the 1× telephoto system, and adjust the relative positions on the axis of the 1× telephoto system 3 and the lens to be tested 4 so that the exit pupil of the former and the entrance pupil of the latter achieve pupil connection;

[0027] Step 3: Turn on the laser simulator 1, and continuously adjust the effective aperture of the adjustable iris 2, so as to adjust the aperture of the entrance pupil 4-1 of the lens 4 to be tested, and obtain the relationship curve between the response voltage of the four-quadrant detector 5 and the aperture of the adjustable iris 2. Since there is a corresponding relationship between the aperture of the adjustable iris 2 and the area of ​​the focused light spot, the relationship curve between the response voltage of the four-quadrant detector 5 (focused light spot energy) and the focused light spot size can be converted, and the focused light spot uniformity curve can be obtained after differentiation;

[0028] Step 4: The single-axis turntable 6 rotates an arbitrary angle ω within the lens field of view, moves the photosensitive surface of the four-quadrant detector, and re-aligns the center of the photosensitive surface of the four-quadrant detector 5 with the lens optical axis. The moving distance Δy is determined by the formula:

[0029] Δy=f'·tanω

[0030] In the formula, f' is the focal length of the lens to be tested. Then repeat steps 1 to 3 to obtain the focus spot uniformity curve of the field of view angle ω of the lens to be tested.

[0031] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A detection system for the energy uniformity of a laser receiving lens focusing spot, characterized in that: It includes a laser simulator, an adjustable diaphragm, a 1× telephoto system, a lens to be tested, a four-quadrant detector and a single-axis turntable, wherein the centers of the photosensitive surfaces of the laser simulator, the adjustable diaphragm, the 1× telephoto system, the lens to be tested and the four-quadrant detector are arranged in sequence along the optical axis, the lens to be tested and the four-quadrant detector are placed on the single-axis turntable, and the center of the entrance pupil optical axis of the lens to be tested coincides with the rotation center of the turntable.

2. A detection system for the energy uniformity of a laser receiving lens focusing spot according to claim 1, characterized in that: The adjustable aperture is placed at the entrance pupil position of the 1× telephoto system.

3. A method for detecting the energy uniformity of the focused spot of a laser receiving lens, based on the detection system described in right 2, characterized in that: The following steps are included: Step 1: Adjust the relative positions of the 1× telephoto system and the lens to be tested on the axis so that the exit pupil of the former and the entrance pupil of the latter can be connected; Step 2, turn on the laser simulator, continuously adjust the effective aperture of the adjustable iris, obtain the relationship curve between the response voltage of the four-quadrant detector and the aperture of the adjustable iris, and use the corresponding relationship between the aperture and the focused spot area to convert the relationship curve between the response voltage and the focused spot size. After data processing, the focused spot uniformity curve can be obtained; Step 3: Rotate the turntable to any angle ω within the lens field of view, radially move the four-quadrant detector photosensitive surface along the direction perpendicular to the optical axis, so that the center of the four-quadrant detector photosensitive surface coincides with the lens optical axis, repeat steps 1 to 2, and obtain the focus spot uniformity curve at any field of view angle.

4. A method for detecting energy uniformity of a laser receiving lens focusing spot as claimed in claim 3, characterized in that: In the step 1, the 1× telescope system is a Keplerian telescope system with a magnification of 1.

5. The method for detecting energy uniformity of a laser receiving lens focusing spot as described in any one of claims 3 to 4, characterized in that: The moving distance Δy of the photosensitive surface of the four-quadrant detector is determined by the formula: Δy=f'·tanω Where f' is the focal length of the lens to be tested.

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