CN-121978826-A - Separated collecting mirror for plasma light source system and manufacturing method thereof

CN121978826ACN 121978826 ACN121978826 ACN 121978826ACN-121978826-A

Abstract

The invention discloses a separated collecting mirror for a plasma light source system and a manufacturing method thereof, which belong to the technical field of plasma light sources, wherein the separated collecting mirror comprises a plurality of fan-shaped plane mirror units and a circular plane mirror, the circular plane mirror is arranged at the center position, and the fan-shaped plane mirror units are arranged around the circular plane mirror; the fan angle of the fan-shaped plane mirror unit is matched and designed according to the luminous cone angle of the plasma light source, and the spliced split collecting mirror keeps consistent reflection and light receiving effects in the whole light-transmitting aperture range. The manufacturing method comprises wedge angle processing, outer arc processing, inner arc transition processing and center circular plane mirror preparation of the fan-shaped plane mirror unit, lens finish polishing processing, a reflecting surface coating process, lens assembly arrangement and clamping fixation. According to the invention, the integral reflecting surface is formed by the plurality of sector plane mirrors, so that the processing difficulty of a single-chip mirror unit can be reduced, and the uniformity of a film layer can be improved by coating the film by unit.

Inventors

HUANG ZEYU
JIN CHUAN
YAN ZILIANG
ZHANG ZEQING
LIU WENJING
LIU JUNBO
KANG XIA
ZHOU JI

Assignees

中国科学院光电技术研究所

Dates

Publication Date: 20260505
Application Date: 20260113

Claims (10)

1. A split type collecting mirror for a plasma light source system is characterized by comprising a plurality of fan-shaped plane mirror units and a circular plane mirror, wherein the circular plane mirror is arranged at the center, the fan-shaped plane mirror units are arranged around the circular plane mirror, the fan-shaped angles of the fan-shaped plane mirror units are matched and designed according to the luminous cone angle of a plasma light source, and the split type collecting mirror after splicing keeps consistent reflection and light receiving effects in the whole light-transmitting caliber range.
2. The split collector mirror for a plasma light source system of claim 1, wherein the fan angle of different sectors is set to be the same or different, adapting to plasma light source systems of different numerical apertures.
3. The split collecting mirror for a plasma light source system according to claim 1, wherein the relative heights of the fan-shaped flat mirror units and the circular flat mirror can be finely adjusted, and the number of the fan-shaped flat mirror units can be adjusted.
4. A method of manufacturing a split collecting mirror for a plasma light source system, for manufacturing the split collecting mirror for a plasma light source system according to any one of claims 1 to 3, comprising: according to the design requirement of a plasma light source system on the focal length of a collecting mirror, calculating the wedge angle parameter required by each fan-shaped plane mirror unit, and carrying out wedge angle processing and grinding on a plane optical substrate to obtain a plurality of initial triangular plane mirrors; step 2, performing arc polishing treatment on each initial triangular plane mirror according to the design requirement of the light transmission diameter of the separated collecting mirror to obtain the outer arc of the fan-shaped plane mirror unit; Step 3, preparing a central circular plane mirror by arc transition processing in the fan-shaped plane mirror units, performing arc transition polishing processing on the tip end part of each fan-shaped plane mirror unit, and processing and grinding a circular plane mirror with the same diameter as the inner arc of each inner arc; Step 4, performing fine polishing processing on the lenses, namely performing fine polishing processing on the front surface, the rear surface and the side surfaces of the fan-shaped plane mirror unit and the circular plane mirror; step 5, carrying out a reflecting surface coating process, namely carrying out reflecting film coating on the reflecting surfaces of the fan-shaped plane mirror units and the circular plane mirrors; step 6, assembling and arranging the lenses, namely arranging the fan-shaped plane mirror units and the circular plane mirrors in a fixing groove of the metal clamping structural member in sequence in a downward direction according to an arrangement mode specified by a design drawing; and 7, clamping and fixing, namely fixing the lenses one by one through the locking limiting holes on the metal clamping structural member, screwing the locking screws into the locking limiting holes, arranging elastic washers or vibration reduction elements at the locking screws, and preventing the locking force from being directly transmitted to the lens main bodies of the sector plane mirror units and the circular plane mirrors to cause deformation of the lenses so as to finish assembly and manufacture of the separated collecting mirrors.
5. The method of claim 4, wherein in step 1, the wedge angle processing is controlled by double-sided grinding.
6. The method of claim 4, wherein in step 2, the outer arc of the fan-shaped plane mirror unit is processed by numerical control sphere polishing or other curve polishing, and the outer diameter dimensional tolerance is controlled within + -0.02 mm to meet the overall light-transmitting aperture precision requirement of the split-type collecting mirror.
7. The method of claim 4, wherein in step 3, the sector-shaped flat mirror unit and the circular flat mirror are made of microcrystalline material or other low thermal expansion optical material, and the linear expansion coefficient is less than 0.02ppm/K.
8. The method of manufacturing a separate collecting mirror for a plasma light source system according to claim 4, wherein step 5 comprises placing the fan-shaped flat mirror units on a plating tool with a boss on one side during plating, supporting the thicker side of the fan-shaped flat mirror units by the boss, and making the reflection surfaces of the fan-shaped flat mirror units on the same horizontal plane under the action of natural gravity, thereby ensuring that the incident angles of all the fan-shaped flat mirror units are consistent during plating, and realizing uniform plating, wherein the plating mode of the reflection surfaces is ion beam assisted plating, electron beam evaporation plating or magnetron sputtering plating.
9. The method of manufacturing a separate collecting mirror for a plasma light source system according to claim 4, wherein in step 6, the metal clamping structure member is circular in shape, the diameter is defined by an outer arc of the fan-shaped flat mirror unit, the inner groove area is used as a fixing groove for fixing the fan-shaped flat mirror unit and the circular flat mirror, a circle of locking limiting holes are formed in the outer side for limiting and fixing the lenses in the fixing groove, and an assembly gap between the fan-shaped flat mirror units is controlled within a range of 0.1-0.3 mm.
10. The method of manufacturing a separate collecting mirror for a plasma light source system according to claim 4, wherein in step 6, a flexible buffer layer is disposed between the outer side of the fan-shaped flat mirror unit and the metal clamping structure member, and the flexible buffer layer is a silica gel pad, a polyimide film or an elastic metal sheet.

Description

Separated collecting mirror for plasma light source system and manufacturing method thereof Technical Field The invention belongs to the technical field of plasma light sources, and particularly relates to a separation type collecting mirror for a plasma light source system and a manufacturing method thereof. Background Plasma light source systems generally have high brightness, high repetition frequency, and strong divergence characteristics, and the radiation source thereof has a large divergence angle after generation, and if effective collection and shaping are not performed, light energy can be quickly attenuated in the propagation process, so that the effective energy utilization rate of a subsequent optical system is reduced. The light source collecting device in the prior art mostly adopts an integral parabolic reflector, and converts divergent light into collimated light through reflection. However, with the improvement of the power of the light source and the improvement of the compactness requirement of the system, the integral parabolic reflector has the typical problems that (1) the caliber of the integral parabolic reflector is large, the curvature radius is small, the surface shape precision is difficult to ensure in the processing process, particularly the edge area is easy to deviate, (2) the parabolic structure is complex, the uniformity of the incident angle and the thickness uniformity of a film layer are difficult to ensure in the film coating process, the reflection efficiency is reduced, and (3) the integral parabolic reflector is heated unevenly under the irradiation of the high-energy plasma light source for a long time to generate thermal deformation, and the light beam pointing stability and the system reliability are influenced. Disclosure of Invention In order to solve the technical problems, the invention adopts the following technical scheme: A split type collecting mirror for a plasma light source system comprises a plurality of fan-shaped plane mirror units and a circular plane mirror, wherein the circular plane mirror is arranged at the center, the fan-shaped plane mirror units are arranged around the circular plane mirror, the fan-shaped angles of the fan-shaped plane mirror units are matched and designed according to the luminous cone angle of a plasma light source, and the split type collecting mirror after splicing keeps consistent reflection and light receiving effects in the whole light-transmitting caliber range. A method of manufacturing a split collecting mirror for a plasma light source system, for manufacturing the split collecting mirror for a plasma light source system, comprising: according to the design requirement of a plasma light source system on the focal length of a collecting mirror, calculating wedge angle parameters required by each fan-shaped plane mirror unit, and carrying out wedge angle processing and grinding on a plane optical substrate to obtain a plurality of initial triangular plane mirrors; step 2, performing arc polishing treatment on each initial triangular plane mirror according to the design requirement of the light transmission diameter of the separated collecting mirror to obtain the outer arc of the fan-shaped plane mirror unit; Step 3, preparing a central circular plane mirror by arc transition processing in the fan-shaped plane mirror units, performing arc transition polishing processing on the tip end part of each fan-shaped plane mirror unit, and processing and grinding a circular plane mirror with the same diameter as the inner arc of each inner arc; Step 4, performing fine polishing processing on the lenses, namely performing fine polishing processing on the front surface, the rear surface and the side surfaces of the fan-shaped plane mirror unit and the circular plane mirror; step 5, carrying out a reflecting surface coating process, namely carrying out reflecting film coating on the reflecting surfaces of the fan-shaped plane mirror units and the circular plane mirrors; step 6, assembling and arranging the lenses, namely arranging the fan-shaped plane mirror units and the circular plane mirrors in a fixing groove of the metal clamping structural member in sequence in a downward direction according to an arrangement mode specified by a design drawing; and 7, clamping and fixing, namely fixing the lenses one by one through the locking limiting holes on the metal clamping structural member, screwing the locking screws into the locking limiting holes, arranging elastic washers or vibration reduction elements at the locking screws, and preventing the locking force from being directly transmitted to the lens main bodies of the sector plane mirror units and the circular plane mirrors to cause deformation of the lenses so as to finish assembly and manufacture of the separated collecting mirrors. The invention has the following beneficial effects: (1) The invention forms the integral reflecting surface by the plurality of fan-shaped pl