A thermal testing device for optical lenses

Abstract

The present invention discloses an athermal test device for optical lenses, including a heating and heat preservation device for heating and heat preservation of a lens to be tested, and also including an image detection system for image detection; the image detection system includes a target generator for generating a light source and an image receiver for receiving detection light, and the image receiver is connected to a computer via a communication cable; the target generator, the lens to be tested and the image receiver are coaxial, and the light emitted by the target generator passes through the lens to be tested and is received by the image receiver. The present invention can heat and heat the lens to be tested by the heating and heat preservation device so that the lens is at different ambient temperatures, thereby performing measurements at different ambient temperatures; a motion device is used to control the displacement of the image receiver to achieve the acquisition of images at different positions (imaging and collecting images at different positions at corresponding temperatures, and finally obtaining the influence of the temperature on the imaging effect of the lens).

Description

Technical Field

[0001] The invention relates to an athermal testing device for an optical lens, belonging to the field of optical detection. Background Art

[0002] Athermalization is a special requirement in the design of optical lenses, especially in fields such as space technology and automotive lenses. The operating temperature of the lens varies greatly, and it is necessary to ensure that the focal length and image clarity of the lens remain unchanged or change very little within this temperature range. Athermalization can be divided into two types: active and passive athermalization. Active athermalization technology uses a pre-set automatic adjustment device to ensure that the optical image quality is not affected when the temperature changes. Passive athermalization considers the impact of temperature changes on the lens and mechanical structure during the design process, and optimizes these changes to offset each other, thereby achieving unchanged image quality.

[0003] The athermal performance of a lens can generally be simulated and analyzed through design software, but due to the tolerance of actual materials and processing and assembly, the simulation analysis will be different from the actual situation. Therefore, the lens needs to measure the defocus and image quality of the lens at different temperatures to provide parameters for active athermal adjustment. Summary of the invention

[0004] Purpose of the invention: The technical problem to be solved by the present invention is to provide an optical lens athermal testing device, which can generate corresponding test temperatures and automatically complete image acquisition and measurement of optical parameters, and can be used to detect the imaging quality and defocus amount of the lens at high and low temperatures.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] An athermal testing device for an optical lens comprises a heating and heat preservation device for heating and heat preservation of a lens to be tested, and also comprises an image detection system for performing image detection; the image detection system comprises a target generator for generating a light source and an image receiver for receiving detection light, the image receiver being connected to a computer via a communication cable; the target generator, the lens to be tested and the image receiver are coaxial, and the light emitted by the target generator passes through the lens to be tested and is received by the image receiver.

[0007] Among them, the heating and heat preservation device includes an insulation pipe, the outside of the insulation pipe is wrapped with a heating belt for heating or insulating the insulation pipe; it also includes a temperature controller, the temperature controller is connected to the heating belt to control the operation of the heating belt; the lens to be tested is fixedly installed in the insulation pipe and coaxial with the insulation pipe; temperature sensors are respectively provided on the inner wall of the insulation pipe and the outer side of the lens to be tested, and the temperature sensors are connected to the temperature controller through cables.

[0008] It also includes a motion control device, which includes a one-dimensional motion platform and a position sensor for detecting position changes of the image receiver; the image receiver is fixed on the one-dimensional motion platform and is driven by the one-dimensional motion platform to move axially.

[0009] Wherein, a window glass is also arranged inside the heat-insulating pipe relative to the front end of the lens to be tested.

[0010] The position sensor comprises a fixed end and a probe, wherein the fixed end is fixed on an image receiver and the probe contacts the end face of the lens to be tested; an elastic device is provided between the probe and the fixed end, and the probe extends or retracts into the fixed end as the position between the lens to be tested and the image receiver changes; the position sensor is connected to a computer via a cable.

[0011] Beneficial effects: The present invention can heat and keep the lens to be tested at different ambient temperatures by means of a heating and heat preservation device; thereby, the lens is placed at different ambient temperatures, and measurements can be performed at different ambient temperatures; a motion device is used to control the displacement of the image receiver, thereby realizing the acquisition of images at different positions; the detection device and the heating device of the present invention are integrated, which simplifies the measurement process and saves measurement space (the device is small in size), and can detect the change in defocus in real time. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 It is a schematic diagram of the system structure of the optical lens athermal testing device of the present invention;

[0013] Figure 2 The image contrast and movement amount curve measured by the optical lens athermalization test device of the present invention;

[0014] Figure 3 The temperature and lens back intercept variation curve measured by the optical lens athermalization testing device of the present invention. DETAILED DESCRIPTION

[0015] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0016] like Figures 1 to 3As shown, the optical lens athermal testing device of the present invention includes a heating and heat preservation device for heating and heat preservation of the lens 104 to be tested (used to change and maintain the ambient temperature of the lens 104 to be tested, and measure the temperature of the lens and the surrounding environment in real time through a temperature controller), and also includes an image detection system for image detection (the image detection system is used to detect the resolution of lens imaging and find the optimal imaging position of the lens); the image detection system includes a target generator 106 for generating a light source and an image receiver 107 for receiving detection light, and the image receiver 107 is connected to an external computer 110 via a communication cable; the target generator 106, the lens 104 to be tested and the image receiver 107 are coaxial, and the light sent by the target generator 106 passes through the lens 104 to be tested and is received by the image receiver 107.

[0017] The target generator 106 and the image receiver 107 are located on the optical axis of the lens 104 to be tested, and are located on both sides of the lens 104. The light beam generated by the target generator 106 is converged and imaged at the image plane position through the lens 104, and the objective lens of the image receiver 107 is also focused on the image plane position. The image is magnified by the objective lens and imaged on the camera, and is input into the computer 110 for analysis and calculation of the image contrast. The image receiver 107 is located on a one-dimensional linear motion platform 108, and can move forward and backward along the optical axis direction of the lens 104 to obtain image contrast at different positions. The position sensor 109 (used to detect the defocus change) includes a fixed end and a probe. The fixed end of the position sensor 109 is fixedly connected to the image receiver 107, and the probe of the position sensor 109 is in contact with the flange surface on the right side of the lens 104. When the image receiver 107 moves forward and backward to scan, the position sensor 109 can accurately measure the distance change between the flange surface of the lens 104 and the image receiver 107. The image receiver 107 can move forward and backward along the lens optical axis to scan images at different positions, and analyze the image contrast through a computer to generate a curve relationship between the contrast and the movement amount to determine the position with the maximum image contrast (the clearest image).

[0018] The lens 104 is clamped in an insulation pipe 102, and the flange surface of the lens 104 is fixed to the inner wall of the pipe 102. There is a window glass 105 on the left side of the lens 104, which allows the light beam generated by the target generator 106 to enter the lens 104, while sealing the internal surrounding environment to have a heat preservation effect. A layer of heating belt 101 is wrapped around the insulation pipe 102, and the heating belt 101 is controlled by the temperature controller 100 to heat or keep warm. The temperature controller 100 is connected to two temperature sensors 103, which are respectively located on the inner wall of the insulation pipe 102 and the outer wall of the lens 104, to measure the temperature of the lens and the surrounding environment in real time.

[0019] The specific detection steps of the optical lens athermalization test device of the present invention are:

[0020] Step 1: Set a specified lens temperature on the temperature controller 100, and the temperature controller 100 controls the heating belt 101 to heat according to the temperature information measured in real time by the temperature sensor 103; when the temperature of the lens 104 reaches the set temperature, the controller 100 controls the heating belt 101 to keep warm for a period of time to ensure that the overall temperature of the lens 104 tends to be constant;

[0021] Step 2: The one-dimensional motion platform 108 drives the image receptor 107 to scan and collect images according to the preset step length and movement range. The image is analyzed by the computer 110 to obtain a curve of image contrast and movement amount, such as Figure 2 , and control the motion platform 108 to move to the optimal contrast position; obtain the defocus amount at the corresponding temperature;

[0022] Step 3: Record the image contrast and position sensor information, and calculate the defocus amount through the image contrast and movement amount curve.

[0023] The temperature controller 100 is used to set a new temperature for the lens to be tested, and the above steps are repeated. The curve of image contrast and movement at the new temperature and the defocus at this temperature are obtained. That is, by setting multiple different temperatures and repeating the above measurement steps, the change of defocus at different temperatures can be obtained and the curve of temperature and lens back intercept change can be plotted, such as Figure 3 This curve will reflect the changes in defocus and image quality of the optical lens as the operating temperature changes.

Claims

1. An optical lens athermalization testing device, characterized in that: The invention comprises a heating and heat preservation device for heating and heat preservation of the lens to be tested, and also comprises an image detection system for performing image detection; the image detection system comprises a target generator for generating a light source and an image receiver for receiving detection light, and the image receiver is connected to a computer via a communication cable; the target generator, the lens to be tested and the image receiver are coaxial, and the light emitted by the target generator passes through the lens to be tested and is received by the image receiver; The invention also includes a motion control device, which includes a one-dimensional motion platform and a position sensor for detecting the position change of the image receiver; the image receiver is fixed on the one-dimensional motion platform and driven by the one-dimensional motion platform to move axially; the position sensor includes a fixed end and a probe, the fixed end is fixed on the image receiver, and the probe touches the end face of the lens to be tested; an elastic device is arranged between the probe and the fixed end, and the probe extends or retracts into the fixed end as the position between the lens to be tested and the image receiver changes; The specific detection steps of the above optical lens athermalization test device are as follows: (1) the specified lens temperature is set on the temperature controller, and the temperature controller controls the heating belt to heat according to the temperature information measured in real time by the temperature sensor; when the lens temperature reaches the set temperature, the controller controls the heating belt to keep warm for a period of time to ensure that the overall temperature of the lens tends to be constant; (2) the one-dimensional motion platform drives the image receiver to scan and collect images according to the pre-set step length and movement range, and the image is analyzed by the computer to obtain the curve of image contrast and movement amount, and the motion platform is controlled to move to the optimal contrast position; the defocus amount at the corresponding temperature is obtained; (3) multiple different temperatures are set to repeat The above detection steps can obtain the change of defocus at different temperatures and draw a curve of temperature and lens back intercept change; record the information of image contrast and position sensor, and calculate the defocus through the curve of image contrast and movement; the heating and insulation device includes an insulation pipe, and the outside of the insulation pipe is wrapped with a heating belt for heating or insulating the insulation pipe; it also includes a temperature controller, and the temperature controller is connected to the heating belt to control the operation of the heating belt; the lens to be tested is fixedly installed in the insulation pipe and coaxial with the insulation pipe; temperature sensors are respectively provided on the inner wall of the insulation pipe and the outer side of the lens to be tested, and the temperature sensors are connected to the temperature controller through cables.

2. The optical lens athermalization testing device according to claim 1, characterized in that: A window glass is also arranged inside the heat-insulating pipe relative to the front end of the lens to be tested.

3. The optical lens athermalization testing device according to claim 1, characterized in that: The position sensor is connected to the computer via a cable.

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