Technological trends related to anti-reflective window glass

Patent applications for sun visors, light control film, and blinds technology

2020/11/06

Summary

  This report created by MarkLines focuses on a number of recent technical topics surrounding the automotive industry and is based on patent information from the “Technology Information Distribution Service - swimy” obtained by the Toyota Technical Development Corporation (TTDC). The two business areas of TTDC are in the fields of intellectual property and measurement control solutions. The intellectual property (IP) side of TTDC is involved in the collection and analysis of information on automotive technology developments globally, and provides services such as consulting for research planning, applying for patents in foreign languages, and technical translation.

  With the spread of autonomous driving technology, the way people spend their time in their cars on the move is expected to change significantly. Therefore, there is a need for a cabin interior environment that meets a variety of needs. The following is a summary of the technologies and developments by various manufacturers of anti-reflective (AR) window glass technologies, such as shading with equipment and the control of light on the glass surface, to adjust the amount of light in the cabin and to improve the appearance of the interior of the vehicle.

  In terms of window glass anti-reflective technology, the number of patent applications are highest in the order of BOS, Saint-Gobain and DNP, and the number of patent applications for "sun visors," "light control film"*, and "blinds" technology is high. BOS Automotive Products, Inc. has a large number of patent applications related to "blind" technology, and Saint-Gobain Corporation and Dai Nippon Printing Co., Ltd. (DNP) have a large number of patent applications related to "light control film" technology. The number of patent applications filed for "sun visor" and "blind" technology is trending downwards, while the number of patent applications for "light control film" technology is on an upward trend.

  *Note: The term "light control film" includes not only thin films that are applied but also functional members in the form of layers.


トヨタテクニカルディベロップメント株式会社

Source: Technical information distribution service - swimy URL: http://www.toyota-td.jp/business/ip/swimy/
This source (TTDC) has extensive content related to automobiles. Graphs can be created for contents of interest with a single click. The database also supports the detailed display and download of intellectual property related information.


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Technological trends related to anti-reflective window glass

[Selection Criteria]

Theme Technological trends related to anti-reflective window glass
Overview Extract patent applications and utility model applications for technology related to anti-reflective window glass.
Period Gazettes of patent applications and utility model applications whose filing and priority years are after 2000 and published before October 2020.
Country, Region Japan
Applicant Unspecified

 

Number of patent applications by each company

  The number of patent applications related to anti-reflective window glass in Japan is highest in the order of BOS, Saint-Gobain and DNP.

各社の特許出願件数
Figure 1 Number of patent applications filed by each company

Source: Technical Information Distribution Service - swimy URL: https://thinktank.toyota-td.jp/pub/list

 



Technology classification

  In the technology related to anti-reflective window glass, many of the technologies are related to the structure of the window glass, and the technical features of the patent documents are expressed in the drawings rather than in the abstract section. For this reason, it is believed that by using the information in the representative drawings in addition to the abstract, which is textual information, it is possible to obtain from the representative diagrams the features that are not shown in the abstract and to classify the technology so that it more accurately reflects the characteristics.

  Therefore, unsupervised classification by machine learning was performed using summaries of the text data and representative figures of the image data. The classification results are shown in "Figure 2: Number of patent applications for each technology classification".

  As a result of the classification, we can obtain the following technical classifications: "sun visors," "light control film," "blinds," "other," "intermediate layer," "laminated glass," and "lamination material”. Of these, the number of patent applications is highest in the order of "sun visors," "light control film," and "blinds".

各技術分類の特許出願件数
Figure 2: Number of patent applications for each technology classification

Source: Technical Information Distribution Service - swimy URL: https://thinktank.toyota-td.jp/pub/list

 

Technology initiatives related to anti-reflection window glass by manufacturer

  BOS, Saint-Gobain, and DNP each have a large number of patent applications, with BOS having the largest number of patent applications in the order of "blinds" and "sun visors".

  Saint-Gobain and DNP filed the largest number of patent applications in the order of "light control film" and "sun visors".

各社の取り組み
Figure 3: Initiatives by manufacturer

Source: Technical Information Distribution Service - swimy URL: https://thinktank.toyota-td.jp/pub/list

 

Annual changes for each technology classification

  Regarding the development trend of each of the technology classifications of "sun visors", "light control film", and "blinds", for which there have been a large number of patent applications, the number of patent applications for “sun visors” peaked in 2004 and has been shrinking over the past several years. The number of applications for "blinds" peaked in 2007, and has been shrinking in recent years. Also, in recent years, the number of applications for "light control film" has been increasing.

  The annual trend of each technology category suggests that the development of light control film tends to be more prolific than that of sun visors and blinds, which are conventional mechanical light control methods for window glass.

各技術分類の年推移
Figure 4: Annual changes for each technology classification

Source: Technical Information Distribution Service - swimy URL: https://thinktank.toyota-td.jp/pub/list

 



Initiatives by each manufacturer regarding future technological trends in the field of "light control film"

  The number of patent applications is highest in the order of Saint-Gobain, DNP, and LG CHEM.

「調光フィルム」の各社の取り組み
Figure 5: Initiatives by manufacturer for “light control film”

Source: Technical Information Distribution Service - swimy URL:https://thinktank.toyota-td.jp/pub/list


  Regarding "light control film", below examples are introduced for DNP, Saint-Gobain, and LG CHEM, which have the largest number of patent applications.

 

Technical example of DNP's technical classification for "light control film"

  Light control film for vehicles (Patent gazette 2018-18074)

面内において明暗の変化が可能な調光フィルム
Figure 6: Light control film capable of changing light and shade in a surface

Source: Technical Information Distribution Service - swimy URL: https://thinktank.toyota-td.jp/pub/list


  When a potential difference is applied between the transparent electrodes of a conventional liquid crystal-based light control film, the light transmittance of the film changes according to the potential difference, but the light transmittance within the surface of the film is almost constant.

  To address this issue, light control film is arranged between two electrodes (22A, 22B) opposed to each other, and multiple power supplies (201, 202, 203, 204) are provided for each of the two electrodes (22A, 22B). By adjusting the multiple power supplies, the gradients of multiple potential differences can be changed to increase or decrease the contrast of light and shade, so the light transmittance can be arbitrarily changed within the surface of the light control film to change the brightness.

 

Technical example of Saint-Gobain's technical classification for "light control film"

  Light control device for vehicles (Patent gazette 2016-505867)

光強度を制御できる調光フィルムガラス
Figure 7: Light control film glass that can control light intensity

Source: Technical Information Distribution Service - swimy URL: https://thinktank.toyota-td.jp/pub/list


  When driving a vehicle, the vehicle may be subjected to very large changes in external light intensity, and if there is a large contrast between strong and weak light in the field of view, it is difficult for the human eye to recognize the information contained in the weak light, which may lead to a traffic accident.

  Conventional methods include the installation of a sun visor in the upper area of the front window of the vehicle and the tinting of a plastic intermediate layer film (e.g., PVB film) sandwiched between the upper portions of the laminated windshield to make the corresponding portion of the windshield opaque.

  However, this would require manual adjustment of the sun visor, which would be detrimental to safe driving. In the colored plastic interlayer film, since the film is fixed, external light cannot penetrate the windscreen and effectively increase the light intensity inside the vehicle.

  To address the above issues, a polymer dispersed liquid crystal (PDLC) film arranged in a portion of the glass corresponding to the desired shading position is provided, and a regulator for adjusting the power supply and voltage is connected to the PDLC film. Furthermore, by equipping a sensor to acquire light intensity information and mounting a controller to adjust the voltage according to the light intensity information, the PDLC film is affixed on the glass corresponding to the desired light-shielding position, and the light transmittance of the glass corresponding to the desired shading position can be controlled by adjusting the voltage supplied to the PDLC film.

  When shading is required, a relatively low voltage is supplied to the PDLC film such that the value of the light transmittance of the glass at the corresponding location becomes smaller. When shading is not required, the glass transmittance can be adjusted in a simple and effective manner by supplying a relatively high voltage to the PDLC film such that the value of the glass transmittance at the corresponding location increases, thereby improving user comfort.

 

Technical example of LG CHEM's technical classification for "light control film"

  Light element (Patent gazette 2020-024437)

熱変形を抑制できる光素子構造
Figure 8: Optical element structure that can suppress thermal deformation

Source: Technical Information Distribution Service - swimy URL: https://thinktank.toyota-td.jp/pub/list


  Conventional optical elements had issues with decreased durability because the elements warped due to the difference in the modulus of elasticity and coefficient of thermal expansion between the substrate and other layers due to heat.

  To address this issue, a polarization layer (200) is arranged adjacent to the first substrate (100a) and the polarization layer (200) is located on the opposite side of the surface where the first substrate (100a) is located. By providing a structure having a liquid crystal window (300) including a liquid crystal layer (301) having a liquid crystal compound, and placing the first substrate (100a) and the polarization layer (200) adjacent to each other, the coefficient of thermal expansion and the stresses that can be generated due to differences in the modulus of elasticity between the layers of the first substrate (100a), the polarization layer (200) and the liquid crystal window (300) are minimized. As a result, it is possible to suppress a decrease in durability due to thermal deformation of the optical elements (1000).


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Keywords
TTDC, Patent, Anti-glare, Window Glass, Sun Visor, Light Control Film, Blind, BOS, SAINT-GOBAIN, DNP, LG CHEM

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