PATENT DOCUMENT

Publication Number: US-10054720-B2
Application Number: US-201514754557-A
Country: US
Kind Code: B2

Title: Fresnel lens barrier rings

Abstract:
A Fresnel lens can be adhered to a window in an optical apparatus by liquid optically clear adhesive (LOCA). However, during adhesion the LOCA may spill over into grooves of the Fresnel lens, and the grooves can carry the LOCA into an active area of the lens potentially causing visual artifacts and altering the functional and cosmetic optical qualities of the lens. In examples of the disclosure, one or more grooves along the circumference of a surface of the lens surrounding inner grooves of the Fresnel lens can form a barrier ring that prevents the LOCA from reaching the inner grooves.

Claims:
What is claimed is: 
     
       1. A lens having a surface with a circumference, the lens comprising:
 a first set of one or more semi-circular grooves in the surface that are not concentric with the circumference of the surface; and 
 a second set of one or more grooves in the surface that are concentric with the circumference of the surface and that surround the first set of grooves, wherein an end of at least one groove of the first set of grooves intersects with at least one groove of the second set of grooves. 
 
     
     
       2. The lens of  claim 1 , wherein the lens is adhered, on an additional surface of the lens opposite the surface that includes the first and second sets of grooves, to a window. 
     
     
       3. The lens of  claim 1 , wherein the first set includes a first groove having a first cross-sectional shape, and the second set includes a second groove having a second cross-sectional shape different from the first cross-sectional shape. 
     
     
       4. The lens of  claim 2 , wherein the lens is adhered via a liquid adhesive, and the liquid adhesive is present in at least an outermost groove of the second set of grooves. 
     
     
       5. The lens of  claim 3 , wherein the first groove is tapered such that it narrows to a v-shaped corner at a deepest portion of the first groove and the second groove includes a flat surface at a deepest portion of the second groove. 
     
     
       6. The lens of  claim 3 , wherein the second groove is narrower at a surface portion of the second groove than at a portion of the second groove that is deeper than the surface portion. 
     
     
       7. The lens of  claim 3 , wherein the second groove is deeper than the first groove. 
     
     
       8. The lens of  claim 3 , wherein the second groove is wider than the first groove. 
     
     
       9. The lens of  claim 3 , wherein a volume of a cavity formed by the second groove is greater than a volume of a cavity formed by the first groove. 
     
     
       10. The lens of  claim 3 , wherein the first groove includes two sides that meet at a deepest portion of the first groove, the first groove includes no more than two sides, and the second groove includes more than two sides, including a flat surface at a deepest portion of the second groove. 
     
     
       11. A lens having a surface with a circumference, the lens comprising:
 a first set of one or more semi-circular grooves in the surface that are not concentric with the circumference of the surface; and 
 a second set of one or more grooves in the surface that define an annular portion of the surface surrounding the first set of grooves, wherein an end of at least one groove of the first set of grooves intersects with at least one groove of the second set of grooves, 
 wherein the grooves of the second set spiral inwards, forming a barrier ring surrounding the first set of grooves. 
 
     
     
       12. The lens of  claim 11 , wherein the grooves of the second set are offset with respect to the circumference of the surface such that the grooves of the second set are non-concentric with the circumference, forming form a barrier ring surrounding the first set of grooves. 
     
     
       13. The lens of  claim 11 , wherein the grooves of the second set form a non-circular path along the annular portion of the surface surrounding the first set of grooves. 
     
     
       14. The lens of  claim 11 , wherein the first set includes a first groove having a first cross-sectional shape, and the second set includes a second groove having a second cross-sectional shape different from the first cross-sectional shape. 
     
     
       15. The lens of  claim 11 , wherein the lens is adhered, on an additional surface of the lens opposite the surface that includes the first and second sets of grooves, to a window. 
     
     
       16. The lens of  claim 15 , wherein the lens is adhered via a liquid adhesive, and the liquid adhesive is present in at least an outermost groove of the second set of grooves.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is the non-provisional application of U.S. Patent Application No. 62/110,979, filed Feb. 2, 2015, which is incorporated by reference in its entirety for all purposes. 
     FIELD OF THE DISCLOSURE 
     The present disclosure relates generally to lenses such as Fresnel lenses. 
     BACKGROUND OF THE DISCLOSURE 
     A Fresnel lens can be adhered to a window in an optical apparatus by liquid optically clear adhesive (LOCA). However, during adhesion the LOCA may spill over into grooves of the Fresnel lens, and the grooves can carry the LOCA into an active area of the lens potentially causing visual artifacts and altering the functional and cosmetic optical qualities of the lens. 
     SUMMARY OF THE DISCLOSURE 
     In examples of the disclosure, one or more grooves along the circumference of a surface of the lens surrounding inner grooves of the Fresnel lens can form a barrier ring that prevents the LOCA from reaching the inner grooves. The lens can include a first set of one or more grooves in the surface that are not concentric with the circumference of the surface, and a second set of one or more grooves in the surface that are concentric with the circumference of the surface and that surround the first set of grooves, forming a barrier ring. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a better understanding of the various described embodiments, reference should be made to the Detailed Description below, in conjunction with the following drawings in which like reference numerals refer to corresponding parts throughout the figures. 
         FIG. 1A  illustrates a top view of a Fresnel lens having grooves that are not concentric with a circumference of a surface of the lens, according to embodiments of the disclosure. 
         FIG. 1B  illustrates a side view of a Fresnel lens adhered to a window using liquid optically clear adhesive, according to embodiments of the disclosure. 
         FIG. 2  illustrates a top view of a Fresnel lens including a first set of grooves that are not concentric with a circumference of a surface of the lens and a second set of grooves that form a barrier ring along the circumference, according to embodiments of the disclosure. 
         FIG. 3A  illustrates a top view of a Fresnel lens including a first set of grooves that are concentric with a circumference of a surface of the lens and a second set of grooves that form a barrier ring along the circumference, according to embodiments of the disclosure. 
         FIG. 3B  illustrates a side view of a Fresnel lens including a first set of grooves that are concentric with a circumference of a surface of the lens and a second set of grooves that form a barrier ring along the circumference, according to embodiments of the disclosure. 
         FIG. 3C  illustrates a side view of a Fresnel lens including a first set of grooves that are concentric with a circumference of a surface of the lens and a second set of grooves that form a barrier ring along the circumference, according to embodiments of the disclosure. 
         FIG. 4  is a block diagram of a method of forming a lens, according to examples of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description of examples, reference is made to the accompanying drawings which form a part hereof, and in which it is shown by way of illustration specific examples that can be practiced. It is to be understood that other examples can be used and structural changes can be made without departing from the scope of the disclosed examples. 
     A Fresnel lens can be adhered to a window in an optical apparatus by liquid optically clear adhesive (LOCA). However, during adhesion the LOCA may spill over into grooves of the Fresnel lens, and the grooves can carry the LOCA into an active area of the lens potentially causing visual artifacts and altering the functional and cosmetic optical qualities of the lens. In examples of the disclosure, one or more grooves along the circumference of a surface of the lens surrounding inner grooves of the Fresnel lens can form a barrier ring that prevents the LOCA from reaching the inner grooves. 
     Although examples described herein refer to a Fresnel lens, the examples are not so limited and apply more generally to any lenses including one or more grooves. Further, although some examples described herein illustrate a barrier ring including multiple grooves, the examples are not so limited and apply more generally to a barrier ring including only a single groove. Further, although some examples described herein illustrate continuous grooves, the examples are not so limited and apply more generally to lenses with multiple continuous grooves along a single curve. 
       FIG. 1A  illustrates a top view of a Fresnel lens  102  having a plurality of grooves  104  that are not concentric with a circumference of a surface of the lens.  FIG. 1B  illustrates a side view of a Fresnel lens  102  adhered to a window  106  using liquid optically clear adhesive (LOCA)  108  and situated in an optical apparatus  100 . The lens  102  may include the plurality of grooves  104  on a surface of the lens that can act to collimate light that passes through the lens, among other optical qualities inherent in Fresnel lenses. 
     As illustrated in  FIG. 1B , an opposite surface of the lens may be adhered to the window  106 . During adhesion, the LOCA can move up around the sides of the lens, potentially spilling into the grooves  104 . Because the lens  102  has grooves  104  that are not concentric with the circumference of the lens (e.g., the grooves are in a circular pattern with a center different from the center of the circumference of the lens), some of the grooves both intersect the circumference and pass through the center of the lens. If LOCA spills into the grooves  104  near the circumference of the lens  102 , the LOCA can wick along these grooves to the center of the lens, potentially causing visual artifacts and altering the functional and cosmetic optical qualities of the lens. 
       FIG. 2  illustrates a top view of a Fresnel lens  200  including a barrier ring to prevent LOCA from reaching inner grooves of the Fresnel lens. Similar to the lens  102  in  FIGS. 1A and 1B , the lens  200  in  FIG. 2  can include a first set of grooves  202  that are not concentric with the circumference of the surface of the lens (e.g., the grooves of the first set are in a circular pattern with a center different from the center of the circumference of the surface). However, the lens  200  can further include a second set of grooves  204  in the surface that are concentric with the circumference of the surface (e.g., the grooves of the second set are in a circular pattern with a center the same as the center of the circumference of the surface). Further, the second set of grooves  204  can surround the first set of grooves  202 , thereby forming a barrier ring between the circumference of the surface and the first set of grooves to prevent LOCA from entering the first set of grooves. 
     For example, the lens  200  may be adhered, on an additional surface of the lens opposite the surface that includes the first and second sets of grooves, to a window, similar to the optical apparatus illustrated in  FIG. 1B . During adhesion, excess liquid adhesive can move around the edges of the lens  200  and onto the surface of the lens including the first and second sets of grooves. The second set of grooves  204  can act as a barrier, containing any excess adhesive before it can reach the first set of grooves  202 . Accordingly, after adhesion the liquid adhesive may be present in at least an outermost groove of the second set of grooves  204 . However, because the second set of grooves  204  are concentric with the circumference and proximate to the circumference, any LOCA in the second set will remain at the edges of the lens  200  and away from the center of the lens. 
     In some examples, the grooves of the second set define an annular portion of the surface surrounding the first set of grooves. Although the second set of grooves  204  are concentric with a circumference of the lens  200  in  FIG. 2 , examples are not so limited. For example, the grooves of the second set can spiral inwards and still form a barrier ring surrounding the first set of grooves. In some examples, the grooves of the second set can be offset with respect to the circumference of the lens such that the grooves of the second set are non-concentric but still form a barrier ring surrounding the first set of grooves. In some examples, the grooves of the second set can form a wavy, jagged, or other non-circular path along an annular portion of the surface surrounding the first set of grooves. 
       FIGS. 3A and 3B  illustrate a Fresnel lens  300  including a first set of one or more grooves (including first groove  302 ) that are concentric with a circumference of a surface of the lens and a second set of one or more grooves (including second groove  304 ) that form a barrier ring along the circumference. In some examples, the second set of grooves define an annular portion of the surface surrounding the first set of grooves. As illustrated in  FIG. 3B , the first groove  302  has a first cross-sectional shape different from a second cross-sectional shape of the second groove  304 . 
     In some examples, the shape of the first set of grooves is configured to optimally refract light (e.g., to collimate light as in a Fresnel lens), and the shape of the second set of grooves is configured to optimally catch excess liquid adhesive. For example, in  FIG. 3B , the first groove  302  is tapered such that it narrows to a v-shaped corner at its deepest portion, whereas the second groove  304  includes a flat surface at its deepest portion. The flat surface at the bottom of the second groove  304  is configured to catch a larger amount of liquid adhesive than the sharp corner at the bottom of the first groove  302 . Additionally, the second groove  304  can be deeper than the first groove  302  and/or wider than the first groove, and a volume of a cavity formed by the second groove can be greater than a volume of a cavity formed by the first groove. In some examples, the first groove  302  has no more than two sides, and the two sides of the first groove meet at its deepest portion, whereas the second groove  304  has more than two sides, including a flat surface at its deepest portion. In some examples, the second groove  304  is narrower at the surface than it is at a portion deeper than the surface portion (e.g., the width of the second groove expands to catch more liquid adhesive). 
       FIG. 4  is a block diagram of a method of forming a lens according to examples of the disclosure. A lens having a surface with a circumference can be provided ( 401 ). A first set of one or more grooves can be formed ( 403 ) in the surface, wherein the grooves of the first set are not concentric with the circumference of the surface. A second set of one or more grooves can be formed ( 405 ) in the surface, wherein the grooves of the second set are concentric with the circumference of the surface, and the grooves of the second set surround the first set of grooves. 
     In some examples, the lens can include an additional surface opposite the surface that includes the first and second sets of grooves, and the method can further include adhering ( 407 ) the additional surface of the lens to a window (e.g., as illustrated in  FIG. 1B ). In some examples, the lens can be adhered via a liquid adhesive, and, after adhering, the liquid adhesive may be present in at least an outermost groove of the second set of grooves. 
     In some examples, the method illustrated in  FIG. 4  can be performed in any order and some of the steps can overlap. For example, forming the first and second sets of grooves can occur concurrently. 
     Examples of the disclosure can be advantageous in providing a Fresnel lens with barrier rings that prevent LOCA from entering inner grooves of the lens, thereby preventing visual artifacts in the Fresnel lens. 
     Although the disclosed examples have been fully described with reference to the accompanying drawings, it is to be noted that various changes and modifications will become apparent to those skilled in the art. Such changes and modifications are to be understood as being included within the scope of the disclosed examples as defined by the appended claims.

Metadata:
Filing Date: 20150629
Publication Date: 20180821
Grant Date: 20180821
Priority Date: 20150202
Inventors: BLOCK, UEYN L.
HARRISON-NOONAN, TOBIAS J.
NAZZARO, DAVID
Assignee: APPLE INC
CPC Classifications: [{"code": "G02B3/08", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B3/08", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B5/1876", "inventive": false, "first": false, "tree": "[]"}, {"code": "G02B3/08", "inventive": true, "first": false, "tree": "[]"}, {"code": "G02B3/0075", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B3/08", "inventive": true, "first": true, "tree": "[]"}, {"code": "G02B5/1876", "inventive": false, "first": false, "tree": "[]"}]
Family ID: 56554139