Substrate treatment device and method and encoder scale treated by this method

Abstract

A method of forming an encoder scale for a measurement device is disclosed. The method comprises taking a laser and a substrate carrying an etch-resistant film. Parts of the etch-resistant film are removed by use of the laser, thereby forming a pattern on the substrate that defines an encoder scale, and the substrate is etched through the parts of the etch-resistant film that have been removed by the laser.

1 . A method of forming an encoder scale for a measurement device, the method comprising the steps of:
 (i) taking a laser;   (ii) taking a substrate carrying an etch-resistant film;   (iii) using the laser to remove parts of the etch-resistant film, thereby forming a pattern on the substrate that defines an encoder scale; and   (iv) etching the substrate through the parts of the etch-resistant film that have been removed by the laser in the step (iii).   
     
     
         2 . The method according to  claim 1 ,
 wherein the laser is a pulsed laser that generates pulses of light, and   wherein the step (iii) comprises directing the pulses of light toward the substrate.   
     
     
         3 . The method according to  claim 2 ,
 wherein the step (iii) comprises continuously displacing the substrate relative to the laser and using the laser to generate the pulses of light at a rate that produces the pattern, and   wherein the parts of the etch-resistant film are removed while the continuous displacement takes place.   
     
     
         4 . The method according to  claim 3 , further comprising the steps of:
 generating a reference signal defining a series of intervals,   using the laser to produce a laser pulse of the pulses of light at each of the intervals defined by the reference signal,   generating a displacement signal indicative of displacement between the substrate and the laser, and   synchronizing the displacement signal with the reference signal by varying the rate at which the substrate is displaced relative to the laser.   
     
     
         5 . The method according to  claim 2 , wherein the pulses of light generated by the pulsed laser have a pulse duration of a picosecond or lower. 
     
     
         6 . The method according to  claim 2 , wherein the pulses of light generated by the pulsed laser have energy of approximately 0.1 to 5 mJ per pulse. 
     
     
         7 . The method according to  claim 1 , further comprising the step of passing light emitted from the laser through at least one lens to produce an elliptical spot focused on the substrate. 
     
     
         8 . The method according to  claim 1 , wherein the substrate comprises a ring. 
     
     
         9 . The method according to  claim 8 , wherein the pattern defining the encoder scale is formed on the circumferential surface of the ring. 
     
     
         10 . The method according to  claim 1 , wherein the substrate is linear. 
     
     
         11 . The method according to  claim 1 , wherein the pattern defined in step (iii) provides at least one of an absolute scale, an incremental scale, and a reference mark. 
     
     
         12 . The method according to  claim 1 , wherein the substrate is non-transparent. 
     
     
         13 . The method according to  claim 1 , wherein the step (iv) comprises applying a chemical reagent to etch the substrate through the parts of the etch-resistant film removed by the laser. 
     
     
         14 . The method according to  claim 1 , further comprising the step of removing the etch-resistant film. 
     
     
         15 . The method according to  claim 1 , wherein the etch-resistant film is an etch resist. 
     
     
         16 . The method according to  claim 1 , wherein the substrate is a metal substrate. 
     
     
         17 . The method according to  claim 16 , wherein the substrate is a stainless steel substrate. 
     
     
         18 . A method of forming an encoder scale for a measurement device, the method comprising the steps of:
 (a) taking a substrate formed of a reflective material and having a reflective surface;   (b) treating the reflective surface directly to darken the surface, the darkening of the surface reducing the reflectivity of the surface itself; and   (c) using a laser to mark bright lines directly onto the surface, the marking of the bright lines restoring the reflectivity of the surface along the marked bright lines, and the bright lines defining an encoder scale.   
     
     
         19 . The method according to  claim 18 , wherein the step (b) comprises darkening the entire surface by etching. 
     
     
         20 . The method according to  claim 18 , wherein the step (b) comprises darkening the surface by anodizing. 
     
     
         21 . The method according to  claim 18 , wherein the step (c) comprises using a pulsed laser that generates pulses of light that mark the bright lines on the surface. 
     
     
         22 . The method according to  claim 18 , wherein the step (c) comprises displacing the surface relative to the laser while the bright lines are being marked. 
     
     
         23 . The method according to  claim 18 , wherein the step (a) comprises taking a substrate that comprises a ring. 
     
     
         24 . The method according to  claim 18 , wherein the step (a) comprises taking a linear substrate. 
     
     
         25 . The method according to  claim 18 , wherein the bright lines of the step (c) provide at least one of an absolute scale, an incremental scale, and a reference mark. 
     
     
         26 . The method according to  claim 18 , wherein the step (b) comprises darkening the surface by etching. 
     
     
         27 . The method according to  claim 18 , wherein the substrate is non-transparent. 
     
     
         28 . A method of forming an encoder scale for a measurement device, the method comprising the following steps in any suitable order:
 providing a substrate;   providing a substrate treatment device;   providing a control system;   providing a displacement mechanism that provides a displacement signal indicative of displacement;   operating the displacement mechanism to cause continuous relative displacement between the substrate and the substrate treatment device; and   operating the control system to monitor the displacement signal and cause the substrate treatment device to treat the substrate at intervals so as to produce a pattern while the continuous displacement takes place, the control system being further operated to perform a timing comparison step to synchronize the displacement signal and the intervals,   wherein the substrate comprises a surface that has previously been darkened by treating the surface directly by at least one of etching and anodizing, and   wherein the substrate treatment device comprises a laser that marks bright lines directly onto the surface of the substrate.   
     
     
         29 . A method of forming an encoder scale for a measurement device, the method comprising the steps of:
 (i) taking a laser;   (ii) taking a substrate carrying an etch resist; and   (iii) using the laser to remove parts of the etch resist, thereby forming a pattern on the substrate that defines an encoder scale; and   (iv) etching the substrate through the parts of the etch resist that have been removed by the laser in the step (iii).   
     
     
         30 . A method of forming an encoder scale for a measurement device, the method comprising the following steps in any suitable order:
 providing a substrate;   providing a substrate treatment device;   providing a control system;   providing a displacement mechanism that provides a displacement signal indicative of displacement;   operating the displacement mechanism to cause continuous relative displacement between the substrate and the substrate treatment device; and   operating the control system to monitor the displacement signal and cause the substrate treatment device to treat the substrate at intervals so as to produce a pattern while the continuous displacement takes place,   wherein the control system is further operated to perform a timing comparison step of synchronizing the displacement signal and the intervals,   wherein the substrate comprises an etch-resistant film,   wherein the substrate treatment device comprises a laser that removes at least part of the etch-resistant film.   
     
     
         31 . A method of forming an encoder scale for a measurement device, the method comprising the steps of:
 (i) taking a pulsed laser that generates pulses of light;   (ii) taking a non-transparent substrate carrying an etch-resistant film; and   (iii) using the laser to remove parts of the etch-resistant film by directing the pulses of light toward the substrate, thereby forming a pattern on the substrate that defines an encoder scale.   
     
     
         32 . A method of forming an encoder scale for a measurement device, the method comprising the steps of:
 (a) taking a substrate having a bright surface;   (b) treating the bright surface directly to darken the surface, the darkening of the surface reducing the brightness of the surface itself; and   (c) using a laser to mark bright lines directly onto the surface, the marking of the bright lines restoring the brightness of the surface along the marked bright lines, and the bright lines defining an encoder scale.