CN102944533A - Portable stray light detection device of center shielding structure - Google Patents

Abstract

A portable central occlusion structure stray light detection device belongs to the field of optical detection technology. In order to solve the problems of high cost, poor equipment portability and low efficiency of the existing optical lens stray light detection method, the device of the present invention consists of an illumination system, a central occlusion , a limited long-distance imaging system and a CCD system, and each component is placed coaxially; the parallel light emitted by the illumination system is incident on the lens to be inspected, and the light is focused on the central block of the limited long-distance imaging system by the lens to be inspected; Part of the light is scattered by the scattering points on the surface of the lens to be inspected, and after scattering, the light is imaged on the CCD system through a limited long-distance imaging system. The device has the advantages of low cost, high efficiency, and portability.

Description

A portable central blocking structure stray light detection device

technical field

The invention relates to a portable central blocking structure stray light detection device, which belongs to the technical field of optical detection.

Background technique

At present, in high-precision optical systems, stray light directly affects the performance of the system, and the smoothness of the optical lens, which is an important part of the optical system, has always affected the level of stray light in the system. There is no straightforward solution to the astigmatism detection problem. Usually, the atomic force microscope and other microscopic detection instruments are used for microscopic detection, or the lens is assembled into the lens by integrating sphere and other equipment before system detection. These methods have many disadvantages such as high cost, poor equipment portability and low efficiency. The problem of system stray light has also become a bottleneck for the continued development of high-end optical systems.

Contents of the invention

The invention aims to solve the problems of high cost, poor equipment portability and low efficiency of the optical lens stray light detection method in the prior art. The invention provides a portable central blocking structure stray light detection device.

The present invention is achieved through the following technical solutions:

A portable stray light detection device with a central obscuration structure, which is composed of an illumination system, a central obscuration, a limited long-distance imaging system and a CCD system, and the components are coaxially placed; the parallel light emitted by the illumination system is incident on the lens to be inspected , the light is focused on the central block of the finite distance imaging system through the lens to be inspected; part of the light is scattered by the scattering points on the surface of the lens to be inspected, and after scattering, the light is imaged on the CCD system through the finite distance imaging system.

Beneficial effects of the present invention: the illumination system of the device of the present invention provides parallel light, and the parallel light incident on the lens to be inspected will be focused on the central occlusion of the limited long-distance imaging system, and part of the light is incident on the stray point of the lens to be inspected, then After being scattered, the light is imaged on the CCD system through a limited long-distance imaging system after scattering, so as to realize the stray light detection of the lens to be inspected. The device has the advantages of low cost, high efficiency, and portability.

Description of drawings

Figure 1: Schematic diagram of a portable central blocking structure stray light detection device of the present invention.

Fig. 2: Another schematic diagram of a portable central blocking structure stray light detection device of the present invention.

In the figure: 1. Illumination system, 2. Lens to be inspected, 3. Center block, 4. Limited long-distance imaging system, 5. CCD system, 6. Eyepiece system.

Detailed ways

The present invention will be further described below in conjunction with accompanying drawing.

As shown in Figure 1, a schematic diagram of a portable central obscuration structure stray light detection device of the present invention, the device is composed of an illumination system 1, a central obscuration 3, a limited long-distance imaging system 4 and a CCD system 5, and each component is coaxial Placement; the parallel light emitted by the illumination system 1 is incident on the lens 2 to be inspected, and the light is focused by the lens 2 to be inspected to the central block 3 on the limited long-distance imaging system 4; part of the light is scattered by the scattering points on the surface of the lens 2 to be inspected , the scattered light is imaged on the CCD system 5 through the limited long-distance imaging system 4 .

As shown in Figure 2, the parallel light emitted by the illumination system 1 is incident on the lens 2 to be inspected, and the light is focused by the lens 2 to be inspected to the central block 3 on the limited long-distance imaging system 4; part of the light is captured by the surface of the lens 2 to be inspected The scattered light is then imaged by the finite long-distance imaging system 4, and the image of the scattered light is projected to infinity by the eyepiece system 6 for direct observation by human eyes.

The illumination system 1 emits parallel light or beams with a certain divergence angle (convergence angle), and the light is incident on the lens 2 to be inspected. The lens 2 to be inspected focuses the light, and the focus is on the axial direction of the first lens surface of the finite-distance imaging system 4. At the center of the first lens surface, an absorbing or reflective film is plated to form a central occlusion 3, which can block the light energy emitted by the illumination system 1 and focused by the lens 2 to be inspected, while bringing the minimum central occlusion to the system.

The limited long-distance imaging system 4 belongs to short-distance imaging, and the magnification, numerical aperture, and field of view of the system are determined by the area of the lens 2 to be inspected and the inspection accuracy requirements. The system design wavelength is the wavelength of the illumination source. Since there is a certain curvature on the surface of the lens to be inspected 2 and the lens to be inspected has a certain aperture, there will be relatively large aberrations in simple imaging. Limited long-distance imaging system 4 The first doublet lens from the object side is an achromatic lens, the second lens acts as a field mirror and collimator, and the last three lenses are an aplanatic lens group, so that it can be used at a limited distance A clear image of the lens 2 to be inspected is obtained from the image side of the imaging system 4 .

The lens 2 to be inspected is placed at the object distance position of the limited long-distance imaging system 4, and the lens 2 to be inspected is placed coaxially with the limited long-distance imaging system 4, and part of the light from the illumination system 1 is detected by the defects and flaws of the lens 2 to be inspected. Or surface dust scatters to form scattered light. For the limited long-distance imaging system 4, this part of scattered light is emitted by the point light source with the surface of the lens 2 to be inspected as the object distance. The scattered light is imaged by the limited long-distance imaging system 4 . Use the CCD system 5 to receive the image point of the above scattered light, the CCD is placed at the image distance position of the finite distance imaging system and placed coaxially with the finite distance imaging system 4, and the position relationship with the lens 2 to be inspected is conjugate, and the CCD system 5 collects The signal is processed by the computer and observed through the display screen, and the defects of the lens to be inspected, the distribution of defect points and the density of dust pollutants can be observed. Or the eyepiece system 6 is placed behind the limited long-distance imaging system 4, so that the object plane position of the eyepiece system 6 coincides with the image plane position of the limited long-distance imaging system 4, and the image of the scattered light is projected to infinity by the eyepiece system 6, for direct observation by the human eye. This enables stray light detection.

Claims (3)

1. a portable central obscuration structure parasitic light pick-up unit is characterized in that, this device is comprised of illuminator (1), central obscuration (3), finite distance imaging system (4) and CCD system (5), and the coaxial placement of each ingredient; The directional light that illuminator (1) is sent incides on the lens to be checked (2), and light is on lens to be checked (2) focus on central obscuration (3) on the finite distance imaging system (4); Part light is by the scattering point scattering on lens to be checked (2) surface, and light is through being imaged in the CCD system (5) through finite distance imaging system (4) after the scattering again.

2. a kind of portable central obscuration structure parasitic light pick-up unit according to claim 1 is characterized in that central obscuration (3) is positioned at the front surface center of the first lens of finite distance imaging system (4).

3. a kind of portable central obscuration structure parasitic light pick-up unit according to claim 1, it is characterized in that, described CCD system (5) replaces to eyepiece system (6), and light is through being imaged on the object plane position of eyepiece system (6) through finite distance imaging system (4) after the scattering again.

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