CN-121978790-A - High-density periodic two-dimensional grid structure projection method and device

Abstract

The application discloses a high-density periodic two-dimensional grid structure projection method, and belongs to the field of optics. The method comprises the steps of modulating a two-dimensional grid grating by amplitude-phase mixing, wherein a single period unit of the grating is provided with an opaque region and two groups of transparent regions, pi phase difference exists between the two groups of transparent regions, then illuminating the grating, and carrying out two-dimensional grid projection through a projection optical system. According to the method, through mixed modulation of the phase and the amplitude, under the same projection optical system and aperture diaphragm conditions, the limitation of the diaphragm on projection density can be effectively broken through, stable projection of a periodic two-dimensional grid structure with higher density is realized, and compared with a traditional amplitude modulation grid, the grid period is greatly reduced, and the grid density is better improved.

Inventors

• ZHENG SHUIQIN
• ZHANG YANG
• MENG YI

Assignees

• 苏州光子湾科学仪器有限公司

Dates

Publication Date

20260505

Application Date

20260325

Claims (6)

1. 1.A method of projecting a periodic two-dimensional grid structure of high density, the method comprising: the method comprises the steps of adopting amplitude-phase hybrid modulation two-dimensional grid grating for projection, wherein a single period unit of the two-dimensional grid grating is provided with an opaque region and two groups of transparent regions, and pi phase difference exists between the two groups of transparent regions; Illuminating the amplitude-phase hybrid modulation two-dimensional grid grating; and enabling the light field modulated by the amplitude-phase mixed modulation two-dimensional grid grating to pass through a projection optical system, wherein an aperture diaphragm of the projection optical system allows diffracted light of (+/-1 ) orders in the light field to pass through, so that projection of the high-density periodic two-dimensional grid structure is realized.
2. 2. The method of claim 1, wherein the amplitude-phase hybrid modulated two-dimensional grid grating is based on a transparent material.
3. 3. The method of claim 1, wherein the opaque area surface of the amplitude-phase hybrid modulated two-dimensional grid grating is covered with a light blocking layer to achieve amplitude modulation.
4. 4. The method of claim 1, wherein the amplitude-phase hybrid modulation two-dimensional grid grating has a thickness difference between two sets of light-transmitting regions, the difference causing a phase retardation pi produced by the two sets of light-transmitting regions for incident light, respectively, to result in the two sets of light-transmitting regions having pi phase differences for incident light.
5. 5. The method of claim 1, wherein the two sets of light-transmitting areas of the amplitude-phase hybrid modulation two-dimensional grid grating are alternately arranged in a checkerboard pattern, and the junctions of the two sets of light-transmitting areas are light-impermeable areas.
6. 6. A high density periodic two-dimensional grid structure projection device, the device comprising: The system comprises a grating module, a phase-shift module and a phase-shift module, wherein the grating module is used for projecting by adopting an amplitude-phase hybrid modulation two-dimensional grid grating, a lightproof area and two groups of light-transmitting areas are arranged in a single period unit of the two-dimensional grid grating, and pi phase differences exist between the two groups of light-transmitting areas; The illumination module is used for illuminating the amplitude-phase hybrid modulation two-dimensional grid grating; And the projection optical system is used for enabling the light field modulated by the amplitude-phase mixed modulation two-dimensional grid grating to pass through the projection optical system, and an aperture diaphragm of the projection optical system allows diffracted light of (+/-1, + -1) orders in the light field to pass through so as to realize projection of the high-density periodic two-dimensional grid structure.

Description

High-density periodic two-dimensional grid structure projection method and device Technical Field The embodiment of the application relates to the field of optics, in particular to a high-density periodic two-dimensional grid structure projection method and device. Background In the field of optical projection, the periodic two-dimensional grid structure is widely applied to high-precision scenes such as microscopic imaging and photoetching, and the projection density and definition of the periodic two-dimensional grid structure directly determine the upper limit of the performance of related equipment. In the prior art, the projection of a two-dimensional grid structure is mostly dependent on a two-dimensional grid grating with pure amplitude modulation, and the grating realizes light intensity modulation through the alternate arrangement of light transmission areas and light non-transmission areas, so that the grid structure is reproduced on a projection plane. However, in practical application, the diaphragm in the optical system can act as a low-pass filter, the smaller the aperture of the diaphragm is, the stronger the blocking effect on the high-frequency diffraction orders in the light field is, and the dense details of the two-dimensional grid just depend on the presentation of high-frequency information, so that the loss of the high-frequency component can directly lead to the contrast reduction of the grid structure, and even the grid structure completely disappears when serious. In addition, when a pure amplitude modulation two-dimensional grid grating is adopted, the complete two-dimensional grid projection can be obtained only by ensuring that 9 diffraction orders of (1, 1), (1, 0), (1, -1), (0, 0), (0, -1), (-1, 0) and (-1, -1) in the light field can pass through the diaphragm. Disclosure of Invention The embodiment of the application provides a high-density periodic two-dimensional grid structure projection method and device. The technical scheme is as follows: In one aspect, a method for projecting a periodic two-dimensional grid structure with high density is provided, the method comprising: the method comprises the steps of adopting amplitude-phase hybrid modulation two-dimensional grid grating for projection, wherein a single period unit of the two-dimensional grid grating is provided with an opaque region and two groups of transparent regions, and pi phase difference exists between the two groups of transparent regions; Illuminating the amplitude-phase hybrid modulation two-dimensional grid grating; and enabling the light field modulated by the amplitude-phase mixed modulation two-dimensional grid grating to pass through a projection optical system, wherein an aperture diaphragm of the projection optical system allows diffracted light of (+/-1 ) orders in the light field to pass through, so that projection of the high-density periodic two-dimensional grid structure is realized. Optionally, the amplitude-phase hybrid modulation two-dimensional grid grating uses a transparent material as a substrate. Optionally, the surface of the opaque area of the amplitude-phase mixed modulation two-dimensional grid grating is covered with a light blocking layer so as to realize amplitude modulation. Optionally, a thickness difference exists between the two groups of light-transmitting areas of the amplitude-phase hybrid modulation two-dimensional grid grating, and the difference enables the two groups of light-transmitting areas to respectively generate phase delay phase difference pi for incident light, so that the two groups of light-transmitting areas have pi phase difference for the incident light. Optionally, the two groups of light-transmitting areas of the amplitude-phase mixed modulation two-dimensional grid grating are alternately arranged in a checkerboard mode, and the junction of the two groups of light-transmitting areas is a light-proof area. In another aspect, there is provided a high density periodic two-dimensional grid structure projection apparatus, the apparatus comprising: The system comprises a grating module, a phase-shift module and a phase-shift module, wherein the grating module is used for projecting by adopting an amplitude-phase hybrid modulation two-dimensional grid grating, a lightproof area and two groups of light-transmitting areas are arranged in a single period unit of the two-dimensional grid grating, and pi phase differences exist between the two groups of light-transmitting areas; The illumination module is used for illuminating the amplitude-phase hybrid modulation two-dimensional grid grating; And the projection optical system is used for enabling the light field modulated by the amplitude-phase mixed modulation two-dimensional grid grating to pass through the projection optical system, and an aperture diaphragm of the projection optical system allows diffracted light of (+/-1, + -1) orders in the light field to pass through so as to realize projection of the hig