News Column

Patent Issued for Mobile Device and Optical Imaging Lens

July 22, 2014



By a News Reporter-Staff News Editor at China Weekly News -- From Alexandria, Virginia, VerticalNews journalists report that a patent by the inventors Chang, Kuo-Wen (Taichung, TW); Lee, Poche (Taichung, TW); Hsu, Sheng-Wei (Taichung, TW), filed on September 14, 2012, was published online on July 8, 2014.

The patent's assignee for patent number 8773767 is Genius Electronic Optical Co., Ltd. (TW).

News editors obtained the following quote from the background information supplied by the inventors: "The ever-increasing demand for smaller sized mobile devices, such as cell phones, digital cameras, etc. has correspondingly triggered a growing need for smaller sized photography modules contained therein. Size reductions may be contributed from various aspects of the mobile devices, which includes not only the charge coupled device (CCD) and the complementary metal-oxide semiconductor (CMOS), but also the optical imaging lens mounted therein. When reducing the size of the optical imaging lens, however, achieving good optical characteristics becomes a challenging problem.

"US Patent Publication No. 20100253829, US Patent Publication No. 2011013069, US Patent Publication No. 20110249346, US Patent Publication No. 20100254029, U.S. Pat. No. 7,826,151, U.S. Pat. No. 7,864,454, U.S. Pat. No. 7,911,711, U.S. Pat. No. 8,072,695, Taiwan Patent No. M368072, Taiwan Patent No. M369460 and Taiwan Patent No. M369459 all disclosed an optical imaging lens constructed with an optical imaging lens having five lens elements. Those disclosed optical imaging lenses involved use of a shortened length of the optical imaging lens; however, some of lengths of the optical imaging lens remained too long. For example, in the first embodiment of Taiwan Patent No. M368072, the length of the optical imaging lens is around 5.61 mm, which is not beneficial for the smaller design of mobile devices.

"How to effectively shorten the lengths of the optical imaging lens is one of the most important topics in the industry to peruse the trend of smaller and smaller mobile devices. Each of the aforesaid patent documents faces the limitation of the size of the mobile device due to the problem of reducing length of the optical imaging lens. Therefore, there is needed to develop optical imaging lens with shorter lengths, while also having good optical characters."

As a supplement to the background information on this patent, VerticalNews correspondents also obtained the inventors' summary information for this patent: "An object of the present invention is to provide a mobile device and an optical imaging lens thereof. With controlling the convex or concave shape of the surfaces of the lens elements, the central thickness along the optical axis, and the air gap between two lens elements, etc., the lengths of the optical imaging lens is shortened and meanwhile the good optical characters, such as high resolution and the system performance, are sustained.

"In an exemplary embodiment, an optical imaging lens comprises, in order from an object side to an image side, a first lens element, a second lens element, a third lens element, a fourth lens element, and a fifth lens element. The first lens element has positive refractive power and comprises a convex object-side curved surface. The second lens element has negative refractive power and comprises a concave image-side curved surface. The third lens element comprises an object-side curved surface and an image-side curved surface, and the object-side curved surface comprises a concave portion in a vicinity of a periphery of said third lens element and the image-side curved surface comprises a convex portion in a vicinity of a periphery of the third lens element. The fourth lens element comprises a convex image-side curved surface and the fifth lens element comprises an object-side curved surface and an image-side curved surface, wherein the object-side curved surface comprises a convex portion in a vicinity of the optical axis and the image-side curved surface comprises a concave portion in a vicinity of the optical axis. Lens as a whole has only the five lens elements with refractive power, wherein a central thickness of the second lens element along the optical axis is T2, a sum of all air gaps from the first lens element to the fifth lens element along the optical axis is G.sub.aa, and they satisfy the relation: 0.20
"In another exemplary embodiment, other central thickness of lens element along the optical axis and/or other ratio of the central thickness of lens element along the optical axis to the sum of all air gaps could be further controlled, and an example among them is controlling the relation of a central thickness of the third lens element along the optical axis, T3, and the sum of all air gaps from the first lens element to the fifth lens element along the optical axis, G.sub.aa, to satisfy the relation: 0.30<(T3/G.sub.aa)

"Another example embodiment comprises controlling T3 to further satisfy the relation: 0.20
"Yet, another example embodiment comprises controlling T2 and G.sub.aa to further satisfy the relation: 0.21
"Yet, another example embodiment comprises controlling T3 and G.sub.aa to further satisfy the relation: 0.25
"Aforesaid exemplary embodiments are not limited and could be selectively incorporated in other embodiments described herein.

"Lens elements in example embodiments, such as the aforesaid first lens element, second lens element, third lens element, fourth lens element, and fifth lens element, are preferable made by plastic lens element with injection molding. Therefore, the technical barrier and the cost may be affected by the thickness of lens element. For example, if the central thickness of the second lens element along the optical axis, T2, is less than the lower limit, 0.2 (mm), the center of the second lens element may be too thin and cause melting plastic material to fail to pass the mold, and compared with currently technical level, the difficulty and cost for production in such situations are too high. Therefore, the lower limits of the above ranges of T2 and T3 are determined based on currently technical level. Further, the thicknesses of the first lens element, the second lens element, the third lens element, the fourth lens element, and fifth lens element affect the length of the optical imaging lens. For example, if the central thickness of the second lens element along the optical axis, T2, exceeds the upper limit, 0.5 (mm), the second lens element may be too thick and cause the length of the optical imaging lens to be too long and fail to match the request of smaller optical imaging lens. Therefore, the upper limits of above ranges of T2 and T3 are determined based on the preferable length of the optical imaging lens.

"In example embodiments, an aperture stop is provided for adjusting the input of light of the system. For example, the aperture stop is selectively provided but not limited to be positioned at the object side of the first lens element, or positioned between the first lens element and the second lens element.

"In some exemplary embodiments, more details about the convex or concave surface structure and/or the refractive power could be incorporated for one specific lens element or broadly for plural lens elements to enhance the control for the system performance and/or resolution. For example, for the second lens element, an object-side curved surface is comprised, but the object-side curved surface need not be limited to a convex portion in a vicinity of a periphery of the second lens element. An example for illustrating the details broadly for plural lens elements comprises the first lens element having positive refractive power and comprising a convex object-side curved surface; the second lens element having negative refractive power and comprising an object-side curved surface and a concave image-side curved surface; the third lens element comprising an object-side curved surface and an image-side curved surface, wherein the object-side curved surface comprises a convex portion in a vicinity of the optical axis and a concave portion in a vicinity of a periphery of the third lens element, and the image-side curved surface comprises a concave portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the third lens element; the fourth lens element having positive refractive power and comprising a concave object-side curved surface and a convex image-side curved surface; and the fifth lens element having negative refractive power and comprising an object-side curved surface and an image-side curved surface, wherein the object-side curved surface comprises a convex portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the fourth lens element, and the image-side curved surface comprises a concave portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the fourth lens element. Another example for illustrating the details broadly for plural lens elements comprises the first lens element having positive refractive power and comprising a convex object-side curved surface and a concave image-side curved surface; the second lens element having negative refractive power and comprising an object-side curved surface and a concave image-side curved surface, wherein the object-side curved surface of the second lens element comprises a convex portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the second lens element; the third lens element comprising an object-side curved surface and an image-side curved surface, wherein the object-side curved surface comprises a concave portion in a vicinity of the optical axis and a concave portion in a vicinity of a periphery of the third lens element, and the image-side curved surface comprises a convex portion in a vicinity of a periphery of the third lens element; the fourth lens element having positive refractive power and comprising a concave object-side curved surface and a convex image-side curved surface; and the fifth lens element having negative refractive power and comprising an object-side curved surface and an image-side curved surface, wherein the object-side curved surface comprises a convex portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the fifth lens element, and the image-side curved surface comprises a concave portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the fifth lens element. Exemplary embodiments for incorporating details broadly for plural lens elements are not limited to the above examples.

"Further, exemplary embodiments could provide more details about the structure, the refractive power, and/or the aperture stop position for a specific lens element or broadly for plural lens elements to fit variable requests. For example, based on the aforesaid examples, an example embodiment comprises the first lens element comprising a convex image-side curved surface, wherein the object-side curved surface of the second lens element comprises a concave portion in a vicinity of the optical axis and a concave portion in a vicinity of a periphery of the second lens element, the third lens element having positive refractive power, and an aperture stop provided at the object side of the first lens element. Another example embodiment is provided with the first lens element comprising a convex image-side curved surface, wherein the object-side curved surface of the second lens element comprises a convex portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the second lens element, the third lens element having negative refractive power, and an aperture stop provided at the object side of the first lens element. Another example embodiment is provided with the first lens element comprising a concave image-side curved surface, the object-side curved surface of the second lens element comprising a convex portion in a vicinity of the optical axis and a convex portion in a vicinity of a periphery of the second lens element, the third lens element having positive refractive power, and an aperture stop provided between the first lens element and the second lens element. Another example embodiment is provided with the first lens element comprising a concave image-side curved surface, the object-side curved surface of the second lens element comprises a convex portion in a vicinity of the optical axis and a concave portion in a vicinity of a periphery of the second lens element, the third lens element having positive refractive power, and an aperture stop provided at the object side of the first lens element. Similarly, based on the later of the aforesaid examples, more examples could be obtained with the further details listed below, including an example embodiment is provided with the third lens element having positive refractive power, and the third lens element the image-side curved surface comprising a convex portion in a vicinity of the optical axis. Another example embodiment is provided with the third lens element having negative refractive power, and the image-side curved surface of the third lens element comprising a concave portion in a vicinity of the optical axis. Another example embodiment is provided with the third lens element having negative refractive power, and the image-side curved surface of the third lens element comprising a convex portion in a vicinity of the optical axis. It is noted that the examples above may be incorporated into other embodiments if no inconsistencies arise.

"In another exemplary embodiment, a mobile device comprises a housing and an optical imaging lens assembly positioned in the housing. The optical imaging lens assembly comprises a lens barrel, any of aforesaid example embodiments of optical imaging lens, a module housing unit, and an image sensor. The lens comprising five lens elements with refractive power as a whole is positioned in the lens barrel, the module housing unit is for positioning the optical imaging lens, and the image sensor is positioned at the image-side of the optical imaging lens.

"In exemplary embodiments, the module housing unit comprises, but is not limited to, an image sensor base and an auto focus module, wherein the image sensor base is for fixing the image sensor, and the auto focus module comprises a lens seat for positioning the optical imaging lens to control the focusing of the optical imaging lens.

"Through controlling the ratio of at least one central thickness of lens element along the optical axis to a sum of all air gaps between the five lens elements along the optical axis in a predetermined range, and incorporated with the arrangement of the convex or concave shape of the surfaces of the lens element(s) and/or refraction power, the mobile device and the optical imaging lens thereof in exemplary embodiments achieve good optical characters and effectively shorten the lengths of the optical imaging lens."

For additional information on this patent, see: Chang, Kuo-Wen; Lee, Poche; Hsu, Sheng-Wei. Mobile Device and Optical Imaging Lens. U.S. Patent Number 8773767, filed September 14, 2012, and published online on July 8, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8773767.PN.&OS=PN/8773767RS=PN/8773767

Keywords for this news article include: Asia, Taiwan, Genius Electronic Optical Co. Ltd..

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Source: China Weekly News


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