Pancake technology principle
The principle of Pancake's optical solution to achieve folded optical paths is mainly based on four components: linear polarizer (LP), quarter phase retarder (QWP), semi-reflective half mirror (BS) and reflective polarizer (RP or PBS).
Quarter-phase retarder, also called quarter-wave plate, is used to retard circularly polarized light into linearly polarized light through a quarter-phase delay; reflective polarizer is used to transmit and reflect different linearly polarized light ; Semi-reflective semi-lens, also known as beam splitter, is used to divide the incident light into two equal parts, 50% reflection and 50% transmission; linear polarizer can play a filtering role to ensure that only polarized light with a specific orientation can Penetrate and enter the human eye.
There are currently several different technological implementations of Pancake folding optical path designs, including single-chip (1p), two-chip (2p) and multi-chip.
Pancake module processing
The key and difficult aspects of Pancake module processing include coating/lamination and assembly adjustment; high-quality film materials and lamination processes can achieve more stable polarization transmission of light.
Things to consider when assembling the Pancake module:
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Do the paraxial optical axes of all surfaces coincide?
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Do the aspheric axes coincide with the paraxial system axis?
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Are the center thicknesses of the lenses and their distances correct?
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Is the alignment of the individual polarization elements to each other correct?
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Is the required image sharpness achieved?
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Is the exit pupil in the correct position?
The optical path design of Pancake's solution is complex. When assembling screens, lenses, etc., it is necessary to strictly follow the established optical path design. Small differences will lead to changes in the overall optical path of the optical module, so the requirements for assembly and adjustment are relatively high. High-precision AA equipment plays a key role in improving efficiency and yield during the Pancake assembly process.
AA assembly process
The AA process, or Active Alignment, is a technology that determines the relative positions of parts during assembly. In the field of optics, the AA process uses a six-axis platform to control and adjust the relative position and posture of the lens group and the imaging chip, and accurately controls the optical axis center of the lens group, the posture of the lens group, including key parameters such as optical focal length, so that it can match the imaging The position of the chip is precisely controlled, ultimately enabling the optical module to be coupled out to achieve the best imaging effect.
AA active alignment technology can effectively reduce the assembly tolerance of the entire module and effectively improve the consistency of optical products.
Because the Pancake lens uses a folded light path design, the assembly difficulty of the lens increases exponentially. The final effect is greatly affected by the relative position relationship between each surface of the lens (6DOF). A slight error will greatly reduce the user experience.
In order to achieve high-precision assembly of optical lenses and screens, optical grade AA equipment assembly is usually required. In the field of VR optical module AA assembly, one of the two human eye-emulating cameras (NED) or matrix cameras (Telescope) is generally used.
Matrix camera (Telescope) solution:
Advantages: Multiple cameras can customize multiple fields of view, such as 0F, 0.2F, 0.3F, 0.4F, 0.5F, 0.6F, 0.7F, 0.8F, 0.9F, 1F, etc. The MTF value of a single field of view can be accurately measured.
Disadvantages: It is difficult to calibrate the relationship between multiple cameras; it is impossible to test the brightness uniformity of the entire module.
Human eye-like camera (NED) solution:
Advantages: A single camera can cover the entire field of view of the VR module, and can directly test the overall brightness uniformity, optical center (OC) and distortion of the VR module.
Disadvantages: Due to the large depth of field of the lens of a near-eye camera, it is impossible to accurately determine the AA peak value and virtual image distance (VID), resulting in the inability to accurately locate the AA position, and the final measured MTF result is inaccurate.
AA equipment supplier
1. 昆山康泰达电子科技有限公司
Kangtaida Intelligent Technology Co., Ltd. was established in April 2019. The company is located in the German Industrial Park, Zhangpu Town, Kunshan City, Jiangsu Province. It is a high-tech enterprise focusing on the R&D, design, production and sales of automation equipment in the fields of metaverse and precision optics and optoelectronics.
The company has made breakthroughs in optics, image testing algorithms, AI image processing algorithms and other technologies, and has achieved absolute advantages in AA technology in the XR field. In response to the demand for automated production line equipment for Industry equipment research and development experience, forward-looking layout, and seizing opportunities. After more than two years of continuous research and development, iterative upgrades, a variety of automation equipment has been launched: AR/VR optical machine module AA automation equipment, XR optical machine/finished machine Optical performance testing equipment, AR/VR binocular imaging AA equipment, XR optical machine/complete machine automation production line, currently Conteda has established in-depth cooperation with leading enterprises in the industry such as Sunny Group, Goertek, Nedega, and Microray Optics. partnership to provide multiple customers with AA equipment for XR production, with a market share currently exceeding 35%.
2. Shenzhen Huiniu Technology Co., Ltd.
In December 2023, Huiniu Technology's 100-level/1,000-level dust-free production base in Wuyi, Zhejiang officially started construction, covering an area of 6,000 square meters. It is expected to be put into production in Q1 of 2024, with a maximum annual production capacity of 500,000 modules. Huiniu Technology’s Wuyi production base will introduce Huiniu’s self-developed AA equipment and automatic assembly equipment to further improve module assembly accuracy and automation levels to meet the shipping requirements of major customers.
The new production base will be equipped with injection molding machines, coating machines, CNC machine tools, curved surface laminating machines, self-developed HNOTS optical measurement platforms and other equipment. It will have a complete production process covering injection molding, coating, cleaning, processing, assembly, testing and other aspects, and will be ready for mass production. The modules include AR-Birdbath series, VR-Pancake series and AR grating waveguide series.
Huiniu Technology self-developed AA equipment
3. Kunshan Huayu Automation Technology Co., Ltd.
Kunshan Huayu Automation Technology Co., Ltd. is a national high-tech enterprise. The company has been committed to the research and development of automation processes such as assembly, testing, welding, and dispensing. It is a national high-tech enterprise that can provide full-line industrial 4.0 smart factory solutions. In 2017 It was recognized as a Kunshan R&D institution in 2016, and has more than 40 invention patents and more than 10 software products. Cooperating customers include Crystal Optoelectronics, Goertek, etc.
In 2019, Huayu began to get involved in the field of research and development of optical inspection, starting from the direction of automobile light inspection, starting from the light quality control system and information management, ergonomics research and optimization design of passive light-emitting products, and based on this, it quickly expanded to AR/VR and Ergonomics research and design, product development and equipment manufacturing of HUD, etc. Huayu AA assembly equipment uses multiple cameras with a dome structure and a new high-speed and high-precision motion mechanism to adjust and compensate for front-end process assembly tolerances from 6 degrees of freedom.
Figure Huayu AA assembly equipment
4. 深圳中科精工科技有限公司
http://www.ait-prime.com/
Shenzhen Zhongke Precision Technology Co., Ltd. is a national high-tech enterprise integrating R&D, design, manufacturing, sales and service, specializing in special new enterprises. Zhongke Precision provides customers with a series of equipment such as intelligent packaging, testing and inspection, and customized one-stop overall solutions. The company's products are widely used in consumer electronics fields such as smartphones and smart wearable devices, as well as in automotive electronics, metaverse, machine vision, semiconductors, and autonomous driving fields.
Figure AR VR AA equipment
Zhongke Seiko AR VR AA equipment is mainly used for the AA manufacturing process of AR/VR products. It has fully automatic loading and unloading, six degrees of freedom adjustment, and is equipped with a fully automatic precision dispensing system. It is suitable for R&D, laboratories, new product trial production and verification. , mass production.
5. Zhuhai Guanghaojie Technology Co., Ltd.
Zhuhai Guanghaojie Technology Co., Ltd. was established on March 6, 2009. It is an automated intelligent equipment manufacturer with core technologies such as imaging quality analysis and machine vision.
Guanghaojie AR/VR optical module assembly and testing equipment is based on a self-developed high-speed and high-precision six-axis platform. It has a number of new AA algorithms and image analysis algorithms dedicated to XR optical modules. It can provide automatic curved surface coating for Pancake polarizing films and Pancake lenses. Polarization axis angle testing, opto-mechanical color AA assembly, opto-mechanical and waveguide lens AA assembly, opto-mechanical and BB lens AA assembly and other XR advanced optical module core manufacturing process equipment and quality control equipment meet customers' ultra-precision process needs.
6. Shenzhen Kerui Technology Co., Ltd. (002957)
https://www.colibri.com.cn/
Founded in 2001, Kerui Technology is a global supplier of industrial automation equipment and overall intelligent manufacturing solutions. The company is mainly engaged in the research and development, design, production, sales and technical services of industrial automation equipment, as well as precision parts manufacturing. Products mainly include automated testing equipment, automated assembly equipment, automated equipment accessories, and precision parts. Centering on the "3+N" business strategic layout, the business mainly focuses on the mobile terminal industry and new energy industry.
XR optical display module AA
Kerui's AA equipment adopts high-pixel and high-resolution testing instruments and a dedicated AR aperture front lens, self-developed fully automatic 6-axis alignment platform and AA algorithm. It is cost-effective and can be matched with a multi-axis dispensing and curing system to meet the needs of products of different shapes. demand, flexible design, compatible with rapid switching of multiple products, compatible with manual and automatic loading and unloading, and supports barcode management systems and MES customization systems. Functions: visual recognition, optical mechanical modules and optical waveguide AA, dispensing and curing.
7. Shenkoda Intelligent Equipment Co., Ltd. (688328)
Shenkoda Intelligent Equipment Co., Ltd. was established in 2004. Its main business is 3C panel intelligent equipment, semiconductor packaging and testing equipment, and automation core components. Mainly engaged in R&D, design, assembly, debugging integration, sales, service, etc. of intelligent equipment and automation components. Its customers include BOE, JDI, CSOT, Tianma and other well-known domestic and foreign companies.
Through the research and development of VR production equipment in recent years, Shenkoda is now able to provide 3D VR thermoforming laminating equipment, 3D AA gluing equipment and IJP equipment, etc. The above equipment is used in the production end of VR glasses Pancake optical module, the main customers For international first-line well-known customers.
8. Wuxi Zhongjingteng Electronic Technology Co., Ltd.
Wuxi Zhongjingteng Electronic Technology Co., Ltd. was established in 2017. Relying on the integration capabilities of listed automation companies, the company cooperates with research institutes, university laboratories, materials laboratories, etc. in the fields of inkjet printing, EHD, UPD, polarized optics, In the field of MR&AR optics, we will further develop and innovate applications.
The company has complete MR optical laboratories, inkjet printing laboratories, polymer materials laboratories, etc. All laboratories serve the development of new technology implementation processes. Up to now, Zhongjingteng has realized the development and development of process technologies such as optical coating, glue printing, ink printing, nano-silver printing, medical liquid printing, polarized optical optical axis alignment, curved surface forming film, six-degree-of-freedom optical alignment correction, etc. It is widely used in different fields such as display, semiconductor, lithium battery, and medical treatment.
Figure AA mirror display assembly equipment
9. Youxin Intelligent Technology (Wuxi) Co., Ltd.
Youxin Intelligence, an emerging technology company established in 2021, has launched a variety of VR Pancake Apollo series optical-mechanical modules and AR BB modules, relying on the deep accumulation and exploration of team members in the fields of VR/AR and core optics. Comprehensively lay out VR Pancake, AR BB, LBS, CPO and other advanced optical technology routes, and can provide ODM/JDM/OEM services according to the needs of partners.
In response to the pain points of low production efficiency, low yield, and high cost in the XR optical machine industry, the company relied on the team’s background experience in optics, electronics, machinery, software, and semiconductors, combined with the process characteristics of optical products, to create the first complete product in China. The highly compatible advanced optical automation production line fully covers the core processes of optical machinery manufacturing, including automatic curved surface lamination, automatic AA coupling, virtual image distance testing and other automated equipment.
Youxin independently develops VR monocular AA coupling equipment, which adopts a self-developed human eye-like vision system and a high-precision AA six-axis platform. It has AA core algorithms, has special-shaped glue and automatic glue line detection functions, and can realize automatic grabbing. , AA, painting glue, detection, curing and other actions.
The information in this article is sourced from the official websites of the respective companies, as well as other online channels, and has been edited by Aibang Zhi Zao.
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The original article was first published on the WeChat official account (Aibang VR Industry News)：VR Pancake process and domestic AA assembly equipment supplier
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