Manufacture of optical light guides

Abstract

The method for manufacturing optical light guide elements comprises a) providing a plurality of initial bars, each initial bar extending along a respective initial-bar direction from a first bar end to a second bar end and having a first side face extending from the first bar end to the second bar end, the first side face being reflective; b) positioning the initial bars in a row with their respective initial-bar directions aligned parallel to each other and with their respective first surfaces facing towards a neighboring one of the initial bars; c) fixing the plurality of initial bars with respect to each other in the position achieved in step b) to obtain a bar arrangement. The method further comprises at least one of the following steps d), d′), d″): d) segmenting the bar arrangement into bars referred to as prism bars each of which comprises a portion of at least two different ones of the plurality of initial bars, by conducting a plurality of cuts through the bar arrangement; in particular wherein the cuts are parallel cuts; d′) segmenting the bar arrangement into bars referred to as prism bars by separating the bar arrangement into parts along cut lines, wherein the cut lines are at an angle with the initial-bar directions; d″) segmenting the bar arrangement into bars referred to as prism bars by separating the bar arrangement into sections by creating cut faces which are at an angle with respect to the initial-bar directions. And the method further comprises e) segmenting the prism bars into parts.

1 . A method for manufacturing optical light guide elements, the method comprising
 a) providing a plurality of bars referred to as initial bars, each initial bar extending along a respective initial-bar direction from a first bar end to a second bar end and having a first side face extending from the first bar end to the second bar end, the first side face being reflective;   b) positioning the initial bars in a row with their respective initial-bar directions aligned parallel to each other and with their respective first surfaces facing towards a neighboring one of the initial bars;   c) fixing the plurality of initial bars with respect to each other in the position achieved in step b) to obtain a bar arrangement;   
       the method further comprising at least one of steps d), d′), d″):
 d) segmenting the bar arrangement into bars referred to as prism bars each of which comprises a portion of at least two different ones of the plurality of initial bars, by conducting a plurality of cuts through the bar arrangement; in particular wherein the cuts are parallel cuts; 
 d′) segmenting the bar arrangement into bars referred to as prism bars by separating the bar arrangement into parts along cut lines, wherein the cut lines are at an angle with the initial-bar directions; 
 d″) segmenting the bar arrangement into bars referred to as prism bars by separating the bar arrangement into sections by creating cut faces which are at an angle with respect to the initial-bar directions; 
 
       the method further comprising
 e) segmenting the prism bars into parts. 
 
     
     
         2 . The method according to  claim 1 , wherein at least one of
 each of the parts is be comprised in one of the optical light guide elements;   each of the parts comprises one of the optical light guide elements.   
     
     
         3 . The method according to  claim 1  or  claim 2 , wherein each of the first side faces comprises a first reflective coating; in particular wherein each of the initial bars has a third side face extending from the first bar end to the second bar end, wherein each of the third side faces comprises a third reflective coating. 
     
     
         4 . The method according to  claim 1  or  claim 2 , wherein each of the first side faces is reflective due to total internal reflection. 
     
     
         5 . The method according to one of  claims 1  to  4 , wherein, in step b), the initial bars are positioned in a distance to each other. 
     
     
         6 . The method according to one of  claims 1  to  5 , wherein each of the initial bars has a first, a second, a third and a fourth side faces, each extending from the first to the second bar end, the first and second side faces being planar faces aligned parallel to each other, the third and fourth side faces being separated from each other by and arranged between the first and the second side faces, in particular wherein the third side face is reflective. 
     
     
         7 . The method according to one of  claims 1  to  6 , comprising
 providing a plate having an upper face and a lower face which are aligned parallel to each other, in particular wherein the upper face and/or the lower face is reflective; 
 obtaining the plurality of initial bars by conducting a plurality of cuts through the plate which run parallel to each other and parallel to the initial-bar directions and which create cut faces which are aligned perpendicularly to the upper and lower faces. 
 
     
     
         8 . The method according to one of  claims 1  to  7 , comprising
 a*) providing a plurality of bars referred to as further bars, each further bar extending along a respective further-bar direction from a first further bar end to a second further bar end; 
 b*) positioning, in step b), each of the further bars between two neighboring ones of the initial bars with their respective further-bar direction aligned parallel to the initial-bar directions; 
 c*) fixing, in step c), the plurality of further bars with respect to each other and with respect to the initial bars in the position achieved in step b) to obtain the bar arrangement. 
 
     
     
         9 . The method according to  claim 8 , comprising
 providing a plate referred to as further plate having an upper face and a lower face which are aligned parallel to each other, in particular wherein the upper face and/or the lower face is reflective;   obtaining the plurality of further bars by conducting a plurality of cuts through the further plate which run parallel to each other and parallel to the further-bar directions and which create cut faces which are aligned perpendicularly to the upper and lower faces.   
     
     
         10 . The method according to one of  claims 1  to  9 , comprising accomplishing the positioning mentioned in step b) by the aid of a jig, in particular comprising holding the initial bars in the jig. 
     
     
         11 . The method according to one of  claims 1  to  10 , wherein the fixing mentioned in step c) comprises attaching a first substrate to the each of the initial bars, in particular wherein the fixing mentioned in step c) comprises, in addition, attaching a second substrate to the each of the initial bars to sandwich the initial bars between the first and second substrates. 
     
     
         12 . The method according to one of  claims 1  to  11 , wherein the cut lines mentioned in steps d′) and d″) and the cuts mentioned in step d), respectively, are at an angle of between 20° and 75° with respect to the initial bar directions, more particularly at an angle of 45° with respect to the initial bar directions. 
     
     
         13 . The method according to one of  claims 1  to  12 , comprising, before step e),
 attaching the prism bars to one or more further substrates, wherein the segmenting mentioned in step e) comprises segmenting the one or more further substrates, in particular wherein each of the at least two parts comprises a section of the one or more further substrates, e.g., a section of each of two further substrates. 
 
     
     
         14 . The method according to  claim 13 , wherein each of the one or more further substrates comprises a wafer on which a plurality of lens elements are present, in particular wherein each of said parts comprises at least one of the lens elements. 
     
     
         15 . An optical light guide element for guiding light incident on the optical light guide element along an incidence direction and exiting the optical light guide element along an exit direction inside the optical light guide element between two reflective faces of the optical light guide element referred to as first and second reflective faces along a main direction of the optical light guide element, wherein the main direction is at an angle with the incidence direction and at an angle with the exit direction, the optical light guide element comprising
 two mutually parallel outer side panels referred to as first and third outer side panels, the main direction being aligned parallel to the first and third outer side panels;   a first prism comprising two base faces aligned parallel to the first and third outer side panels, one attached to the first outer side panel, the other attached to the third outer side panel;   
       wherein the first prism comprises, located between the first and third outer side panels, the first reflective face shaped and aligned for redirecting light incident on the optical light guide element along the incidence direction into the main direction, and wherein the optical light guide element comprises, located between the first and third outer side panels, a second reflective face shaped and aligned for redirecting light redirected by the first reflective face into the main direction to exit the optical light guide element along the exit direction, wherein the second reflective face is
 comprised in the first prism; or 
 comprised in a second prism of the optical light guide element, the second prism comprising two further base faces aligned parallel to the first and third outer side panels, one attached to the first outer side panel, the other attached to the third outer side panel, wherein the second prism comprises, between the two further base faces, the second reflective face.