Patent Publication Number: US-2021181393-A1

Title: Optical film, optical lens, and lens module

Description:
FIELD 
     The subject matter of the application generally relates to an optical film, an optical lens, and a lens module. 
     BACKGROUND 
     A plurality of optical lenses is mounted in an optical lens. Light beams entering into the optical lens can easily be reflected or refracted by the edges of the lenses of the optical lenses, thereby forming stray light. The stray light can affect the imaging quality of the optical lens. 
     A manufacturer may attempt to reduce the effect of stray light on the imaging quality of the optical lenses by providing shading elements or blackening the edges of the optical lenses. However, the assembly accuracy of the optical lens provided with shading elements is not easy to maintain, which will affect the imaging quality of the optical lens. Blackening the edges of the optical lenses is generally not effective in eliminating the effects of stray light. 
     Therefore, there is room for improvement in the art. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Implementations of the present disclosure will now be described, by way of embodiments, with reference to the attached figures. 
         FIG. 1  is a perspective view of an embodiment of an optical lens according to the present disclosure. 
         FIG. 2  is a cross-sectional view along a line II-II of  FIG. 1 . 
         FIG. 3  is a cross-sectional view of an anti-reflection film layer of  FIG. 2 . 
         FIG. 4  is a transmission spectrogram of optical films of the optical lens of various thicknesses shown in  FIG. 1 . 
         FIG. 5  is a reflectance spectrogram of the optical lens of  FIG. 1  with an optical film on one surface of the optical lens. 
         FIG. 6  is a reflectance spectrogram of the optical lens of  FIG. 1  with an optical film on one surface of the optical lens. 
         FIG. 7  is a reflectance spectrogram of the optical lens of  FIG. 1  with an optical film on one surface of the optical lens. 
         FIG. 8  is a perspective view of a lens module including the optical lens of  FIG. 1 . 
         FIG. 9  is a perspective view of an electronic device including the lens module of  FIG. 8 . 
     
    
    
     DETAILED DESCRIPTION 
     It will be appreciated that for simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the embodiments described herein. However, it will be understood by those of ordinary skill in the art that the embodiments described herein can be practiced without these specific details. In other instances, methods, procedures, and components have not been described in detail so as not to obscure the related relevant feature being described. Also, the description is not to be considered as limiting the scope of the embodiments described herein. The drawings are not necessarily to scale, and the proportions of certain portions may be exaggerated to better illustrate details and features of the present disclosure. 
     The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings, in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean “at least one.” 
     The term “comprising” when utilized, means “including, but not necessarily limited to”; it specifically indicates open-ended inclusion or membership in the so-described combination, group, series, and the like. 
       FIGS. 1-2  show an embodiment of an optical lens  100 . The optical lens  100  includes a lens  10  and at least one optical film  20  formed on at least one surface of the lens  10 . 
     The lens  10  has refractive power. The lens  10  is a spherical lens or an aspherical lens. The lens  10  includes a central area  101  and a peripheral area  102  surrounding the central area  101  (the boundary between the central area  101  and the peripheral area  102  is indicated by a thick solid line in  FIG. 1 ). The central area  101  is defined as an optical effective diameter area, which is suitable for passing light, and the diameter of the central area  101  is the clear aperture of the lens  10 . 
     The lens  10  includes a first surface S 3  and a second surface S 4  opposite to the first surface S 3 . In at least one embodiment, the optical film  20  is formed on the second surface S 4 . In other embodiments, the optical film  20  may be formed on the first surface S 3 . 
     The optical film  20  includes at least one light-absorbing film layer  21  and at least one anti-reflection film layer  22  formed on the at least one light-absorbing film layer  21 . 
     The at least one light-absorbing film layer  21  and the at least one anti-reflection film layer  22  are both formed by a sputtering process. 
     A material of the at least one light-absorbing film layer  21  is powders of chromium metal and Si x O y  mixed together, wherein x and y are both greater than 0 and positive integers. In at least one embodiment, the Si x O y  is SiO 2 . 
     In the at least one light-absorbing film layer  21 , a range of the atomic weight content percentage of the chromium powder is from 0% to 30%. 
     Referring to  FIG. 3 , the anti-reflection film layer  22  includes at least one first film layer  221 . A material of the first film layer  221  is one of Si x O y  or Ti m O n , m and n are both greater than 0 and positive integers. In at least one embodiment, the Si x O y  is SiO 2 , and the Ti m O n  is Ti 3 O 5 . 
     The at least one anti-reflection film layer  22  further includes at least one second film layer  222 . The second film layer  222  and the first film layer  221  alternate together. A material of the second film layer  222  is one of Si x O y  or Ti m O n . A material of the second film layer  222  is different from a material of the first film layer  221 . 
     Referring to  FIG. 3 , in this embodiment, the at least one anti-reflection film layer  22  includes two first film layers  221  and two second film layers  222 . The two first film layers  221  and the two second film layers  222  alternate together. In this embodiment, a material of the first film layer  221  is SiO 2 , and a material of the second film layer  222  is Ti 3 O 5 . 
     A thickness of the at least one light-absorbing film layer  21  is defined as H 1 , 450 nm≤H 1 ≤550 nm. A thickness of the at least one anti-reflection film layer  22  is defined as H 2 , 50 nm≤H 2 ≤100 nm, or 300 nm≤H 2 ≤400 nm. 
       FIG. 4  is a transmission spectrogram of the optical films of the optical lens of various thicknesses shown in  FIG. 1 . B/Si means that a material of the at least one anti-reflection film layer  22  formed on the at least one light-absorbing film layer  21  is SiO 2 , and a thickness of the at least one anti-reflection film layer  22  is 70 nm. B/AR6L means that a material of the at least one anti-reflection film layer  22  formed on the at least one light-absorbing film layer  21  is SiO 2 /Ti 3 O 5 , and a thickness of the at least one anti-reflection film layer  22  is 360 nm. B/AR8L means that a material of the at least one anti-reflection film layer  22  formed on the at least one light-absorbing film layer  21  is SiO 2 /Ti 3 O 5 , and a thickness of the at least one anti-reflection film layer  22  is 340 nm. 
       FIG. 5  is a reflectance spectrogram of the optical lens  100  with an optical film  20  on one surface of the optical lens  100 . A thickness of the light-absorbing film layer is 525 nm, a thickness of the anti-reflection film layer is 70 nm, and a material of the anti-reflection film layer is SiO 2 . 
       FIG. 6  is a reflectance spectrogram of the optical lens  100  with an optical film  20  on one surface of the optical lens  100 . A thickness of the at least one light-absorbing film layer  21  is 525 nm, a thickness of the at least one anti-reflection film layer  22  is 360 nm, and a material of the at least one anti-reflection film layer  22  is SiO 2 . 
       FIG. 7  is a reflectance spectrogram of the optical lens  100  with an optical film  20  on one surface of the optical lens  100 . A thickness of the at least one light-absorbing film layer  21  is 525 nm, a thickness of the at least one anti-reflection film layer  22  is 340 nm, and a material of the at least one anti-reflection film layer  22  is SiO 2 . 
     Referring to  FIGS. 4 to 5 , when H 1 =525 nm and H 2 =70 nm, the luminousness of the optical film  20  is less than 7% and the reflectivity of the optical film  20  is less than or equal to 5% in a visible light wavelength range of 400 nm to 700 nm. 
     Referring to  FIGS. 4 and 6 , when H 1 =525 nm and H 2 =360 nm, the luminousness of the optical film  20  is less than 5% and the reflectivity of the optical film  20  is less than or equal to 2% in a visible light wavelength range of 400 nm to 700 nm. 
     Referring to  FIGS. 4 and 7 , when H 1 =525 nm and H 2 =340 nm, the luminousness of the optical film  20  is less than 4% and the reflectivity of the optical film  20  is less than or equal to 1.7% in a visible light wavelength range of 400 nm to 700 nm. 
       FIG. 8  shows an embodiment of a lens module  200 . The lens module  200  includes a shot  201 , the shot  201  includes at least one optical lens  100 . 
       FIG. 9  shows an embodiment of an electronic device  300 . The electronic device  300  includes a body  301  and the lens module  200  mounted in the body  301 . The electronic device  300  may be a smart phone, a tablet computer, or the like. In at least one embodiment, the electronic device  300  is a smart phone. 
     With the embodiments described above, the optical film  20  includes the at least one light-absorbing film layer  21  and the at least one anti-reflection film layer  22 . A material of the at least one light-absorbing film layer  21  is powders of chromium metal and Si x O y  mixed together. Both the chromium metal and the Si x O y  have a high extinction coefficient, which can increase the absorbance of the optical film  20 . Furthermore, a thickness of the anti-reflection film layer  22  of the optical film  20  can be controlled, so that the reflectivity of the optical film  20  can be reduced to below 1.7%, thus stray light and its effect on the imaging quality can be further reduced. 
     The embodiments shown and described above are only examples. Many details are often found in the art such as the other features of an optical film, an optical lens, a lens module, and an electronic device. Therefore, many such details are neither shown nor described. Even though numerous characteristics and advantages of the present disclosure have been positioned forth in the foregoing description, together with details of the structure and function of the present disclosure, the disclosure is illustrative only, and changes can be made in the detail, including in matters of shape, size, and arrangement of the parts within the principles of the present disclosure, up to and including the full extent established by the broad general meaning of the terms used in the claims. It will therefore be appreciated that the embodiments described above can be modified within the scope of the claims.