Processing method for improving imaging quality of cemented prism and cemented prism

Abstract

The invention discloses a processing method for improving imaging quality of a cemented prism and the cemented prism. According to the scheme, the polished glue line is fully protected through the protective film, the situation that the imaging quality is affected due to the fact that the glue line is affected by the subsequent manufacturing procedure is avoided, the process difficulty is greatly reduced, the protective film is formed by moving the first layer or the first layers of the antireflection film to the position after appearance and surface machining, the situation that the subsequent manufacturing procedure influences the glue line is avoided, and the production efficiency is improved. And meanwhile, the overall design and processing of the antireflection film are not influenced, and the yield is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of optical element processing technology, and in particular to a processing method for improving the image quality degradation of cemented prisms caused by stray light during the imaging process. Specifically, it relates to a processing method for improving the imaging quality of cemented prisms and a cemented prism. Background Technology

[0002] As an important optical element, glued prisms are widely used in various optical devices and systems to achieve complex optical functions and precise optical operations. In the present technology, glued prisms are usually made by gluing two or more prisms together with specific glues or adhesive materials.

[0003] For example, such as Figure 1 As shown, the first optical lens 1 and the second optical lens 2 are bonded together by an adhesive layer 3. During the fabrication of the adhesive prism, due to the difference in thermal expansion and contraction between the optical adhesive and the optical lens materials, pits 4 or raised adhesive seams often appear on the side of the adhesive layer, such as... Figure 2 As shown, the impact of the adhesive seam on product imaging increases with the size of the adhesive seam.

[0004] In the original process, after the first and second optical lenses are bonded together with an adhesive layer, they are cut into strip prisms and their surfaces are ground and polished. After polishing, they go through subsequent processes such as strip prism shape processing, ultrasonic cleaning, screen printing and baking, coating, and cleaning.

[0005] During this process, the adhesive joints of the adhesive layer are affected by ultrasonic cleaning, detergents, baking, and other factors. The adhesive joints are easily contaminated by detergents, affecting the refractive index of the adhesive. After cleaning and baking, the adhesive joints will also undergo a certain degree of expansion and contraction, causing the adhesive joints to deteriorate and affecting imaging. The process control is difficult and affects the product processing yield. Summary of the Invention

[0006] To address the aforementioned technical problems, this invention presents a processing method and a cemented prism for improving the imaging quality of cemented prisms. The aim is to provide a prism processing method with a reasonable structural design and excellent optical effects. This method employs a method of polishing a strip prism and then coating it with a protective layer, thereby improving the prism's imaging effect while ensuring its optical performance.

[0007] The present invention adopts the following technical solution: A processing method for improving the imaging quality of cemented prisms includes the following steps: S1. Select the first and second optical lenses with the same refractive index and perform surface processing; S2. Perform patterned film processing on one side of the first optical lens or the second optical lens; S3. Use an adhesive with an equivalent refractive index to form an adhesive layer to bond the first optical lens and the second optical lens together and then cure them. S4. The bonded large optical lens is wire-cut into strip prisms of the required shape. S5. Perform surface processing on the strip prism; S6. A protective layer is deposited on the optical area surface of the strip prism to cover and protect the adhesive seam of the adhesive layer. The surface of the protective layer is not polished. S7. Perform external machining on the strip prism to ensure that the product shape and size meet the design requirements.

[0008] Preferably, in step S6, the protective layer is an antireflective coating layer. The antireflective coating of the subsequent optical coating process is separated, and the first layer or the first few layers of the antireflective coating are removed and directly coated on the optical area surface of the strip prism.

[0009] Preferably, the thickness of the first or first few layers of the antireflective film is in the range of 10-500 nm.

[0010] Preferably, in step S1, the surface processing of the first optical lens and the second optical lens involves wire cutting, grinding and polishing. The surface roughness of the polished lens is Ra < 0.5 nm, TTV < 3 μm, and PV ≤ 25 μm.

[0011] Preferably, in step S2, the thickness of the patterned film layer is 0.5~10 μm.

[0012] Preferably, in step S3, the curing energy of the curing treatment is ≥20000mj / cm2, and the cured product is subjected to high-temperature annealing treatment at a temperature of 100-150℃ for 30-300min.

[0013] Preferably, in step S5, the surface processing involves first grinding the strip prism, then performing protective chamfering, and finally polishing. After polishing, the surface roughness of the product is less than 0.5 nm and PV ≤ 0.3 μm.

[0014] A cemented prism includes a first optical lens and a second optical lens with the same refractive index. A patterned film layer is disposed on the first or second optical lens. The first and second optical lenses are connected by an adhesive layer with equivalent refractive index. After cementation, a protective layer is deposited on the optical area surface of the prism to cover and protect the adhesive seam of the adhesive layer. The protective layer is the first or first few layers of antireflective coating. The surface of the protective layer is not polished.

[0015] Preferably, the first optical lens and the second optical lens are made of the same material, and the requirement for equivalent refractive index means that the absolute value of the difference between the material refractive index and the refractive index of the first optical lens and the second optical lens is kept within 0.05.

[0016] The beneficial effects of this invention are: the protective film solution used in this invention fully protects the glue seam after polishing, avoiding the impact of subsequent processes on the glue seam and thus affecting the imaging quality, greatly reducing the difficulty of the process. The protective film moves the first or first few layers of the antireflective film after the shape and surface processing, avoiding the impact of subsequent processes on the glue seam, while not affecting the overall design and processing of the antireflective film, thus greatly improving the yield. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of a glued prism in the prior art; Figure 2 This is a schematic diagram of the pits in cemented prism products in the prior art; Figure 3 This is a schematic diagram of the adhesive prism structure in this invention; Figure 4 This is the optical path diagram of the cemented prism in this invention; Figure 5 Optical test diagram of a glued prism manufactured using existing technology; Figure 6 This is an optical test diagram of the prism in an embodiment of the present invention; In the diagram: 1. First optical lens, 2. Second optical lens, 3. Adhesive layer, 4. Pits, 5. Protective layer. Detailed Implementation

[0018] The technical solution of the present invention will be further described in detail below through specific embodiments and with reference to the accompanying drawings: Example 1: As Figure 3 As shown, a processing method for improving the imaging quality of a cemented prism, wherein the cemented prism comprises: First optical lens; Second optical lens; A patterned film layer is deposited on the surface of a first or second optical lens; An adhesive layer is used to fix the first optical lens and the second optical lens together; After gluing, a protective layer is deposited on the optical area surface of the prism to cover and protect the glue seam of the glue layer.

[0019] In this embodiment, the first optical lens and the second optical lens are H-Bak7 with a refractive index of 1.568, the patterned film is a black film with low reflection and low transmittance, and the film is coated on the surface of the first optical lens; the adhesive layer material has a refractive index of 1.568.

[0020] The process for preparing cemented prisms is as follows: 1. Optical lens processing: Select suitable transparent materials such as optical glass or quartz as the first and second optical lenses. Perform wire cutting, grinding and polishing on the first and second optical lenses. The surface roughness of the polished lens is Ra < 0.5nm, TTV < 3um, and PV ≤ 25um (Ra refers to the surface roughness of the optical lens, TTV refers to the total dispersion of the optical lens thickness, and PV value refers to the difference between the highest and lowest points on the surface of the optical lens). 2. Patterned coating processing: A patterned coating is processed on one side of the first optical lens, with a coating thickness of 0.9 μm; 3. Optical lens bonding process: The patterned first and second optical lenses are bonded together using adhesive with the same refractive index as the optical lenses and then cured. The curing energy is 50,000 mj / cm2. After curing, the product is subjected to high-temperature annealing at 120℃ for 2 hours. 4. Wire cutting: The bonded large optical lens is wire cut into strip prisms of the required shape. 5. Shape and surface processing: The strip prism after grinding and polishing is shaped and ground and polished to ensure surface smoothness and flatness. The surface roughness of the product is 0.2nm, PV is 0.25um, and the depth of the glue joint pit is 5nm. 6. Deposit a protective layer: Deposit a single layer of SiO2 film with a thickness of 150nm on the optical surface of the prism to fully protect the adhesive layer; 7. Machining of strip prism shape: Milling, roughening and other machining processes are performed on the strip prism to ensure that the product shape and size meet the design requirements; 8. Screen printing: The strip prism is screen printed according to the design requirements. After screen printing, it is heat-cured in a dust-free oven at 100℃ for 120 minutes. 9. Coating: According to the optical design requirements, perform optical thin film processing on the silkscreened elongated prism; 10. Slitting: Slitting the strip prism into the final required prism.

[0021] like Figure 4 The diagram shown is an optical path diagram of the cemented prism in this invention. This invention enables the incident light to undergo total internal reflection at the cemented area at the bottom of the prism, so that the incident light from the first optical lens is completely reflected to the second optical lens when it reaches the cemented bottom, thereby increasing the optical working area of ​​the prism.

[0022] like Figure 5 , Figure 6As shown, the optical test diagrams of the cemented prism of the prior art and the cemented prism of the present invention are shown. As shown in the optical test diagram of the cemented prism, the prism processed by the cementing process of the present invention does not show any diffraction stray light phenomenon in optical imaging. Compared with the cemented prism of the prior art, the optical imaging quality is significantly improved.

[0023] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Other variations and modifications are possible without departing from the technical solutions described in the claims.

Claims

1. A method for improving the imaging quality of a cemented prism, comprising: The method comprises the following steps: ​ S1, selecting first optical lenses and second optical lenses with the same refractive index for surface processing; S2, performing patterned film layer processing on one surface of the first optical lenses or the second optical lenses; S3, using glue with an equivalent refractive index of the optical lenses to form a glue layer to glue the first optical lenses and the second optical lenses and perform curing treatment; S4, performing linear cutting processing on the glued large optical lenses to cut them into strip-shaped prisms with a required shape; S5, performing surface processing on the strip-shaped prisms; S6, plating a protective layer on the optical area surface of the strip-shaped prisms to cover and protect the glue joint in the glue layer, and the surface of the protective layer is not polished; S7, performing shape processing on the strip-shaped prisms to make the shape and size of the product meet the design requirements.

2. The method of claim 1, wherein the method further comprises: In the step S6, the protective layer is an anti-reflection film layer, the anti-reflection film of the later process optical plating is split, and the first layer or the first few layers of the anti-reflection film are directly plated on the optical area surface of the strip-shaped prisms.

3. The method of claim 2, wherein the method further comprises: The first layer or the first few layers of the anti-reflection film have a film thickness in the range of 10-500 nm.

4. The method of claim 1, wherein the method further comprises: In the step S1, the surface processing of the first optical lenses and the second optical lenses is linear cutting and grinding and polishing processing of the first optical lenses and the second optical lenses, and the surface roughness Ra of the polished lenses is less than 0.5 nm, the TTV is less than 3 um, and the PV is less than or equal to 25 um.

5. The method of claim 1, wherein the method further comprises: In the step S2, the film layer thickness of the patterned film layer processing is 0.5-10 um.

6. The method of claim 1, wherein the method further comprises: In the step S3, the curing energy of the curing treatment is greater than or equal to 20000 mj / cm2, and the product after curing is subjected to high-temperature annealing treatment, the annealing temperature of the high-temperature annealing treatment is 100-150℃, and the time is 30-300 min.

7. The method of claim 1, wherein the method further comprises: In the step S5, the surface processing process is to first grind the strip-shaped prisms, then perform protective inverted beveling, and then perform polishing treatment, and the surface roughness of the product after polishing treatment is less than 0.5 nm and the PV is less than or equal to 0.3 um.

8. A cemented prism comprising a first optical lens and a second optical lens of the same refractive index, a patterned film layer being provided on the first optical lens or the second optical lens, the first optical lens and the second optical lens being connected by a cement layer of an equivalent refractive index, characterized in that, A protective layer is plated on the optical area surface of the glued prisms to cover and protect the glue joint in the glue layer, the protective layer is the first layer or the first few layers of the anti-reflection film, and the surface of the protective layer is not polished.

9. A cemented prism according to claim 8, wherein The materials of the first optical lenses and the second optical lenses are the same, and the equivalent refractive index requirement means that the absolute value of the difference between the refractive index of the material and the refractive index of the first optical lenses and the second optical lenses is kept within 0.05.

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