LENS MARKINGS VIEWER

Abstract: In the process for producing ophthalmic progressive lenses, it is common practice to inspect lenses using a lamp and the effects of ambient light refraction to detect surface imperfections as well as for retrieving manufacturers' markings. Such markings containing key process information are mandatory for further finishing and cutting processes of the ophthalmic progressive lenses. In this invention, light is generated by a coherent light source at a given wavelength that may range between 620 and 670 nanometre and collimated prior to being diffused over the surface of the lens under inspection. The lens under inspection may be moved at an angle beta in the path of the diffused light to enhance light refraction occurring onto the markings and other surface imperfections. The light is thus refracted to a projection surface for viewing by the human eye (operator) to clearly examine the markings as well as the surface imperfections before and after coatings and other treatments. In this invention, the optical apparatus is contained into an instrument which encompasses all of the necessary mechanism to enable the examination of most types of ophthalmic lenses. The angle beta may be modified by the operator to adapt to different lenses' curvature. This is achieved by manipulation of a controller arm until optimum viewing is achieved. The light source intensity as well as focus may be adjusted during the process of examining lenses.

Description: O 95/19558 LENS MARKINGS VIEWER DESCRIPTION This invention relates to an instrument containing an optical apparatus and mechanisms for inspecting ophthalmic progressive lenses for the viewing of markings and imperfections. It is common in processes for inspecting lenses or for retrieving markings on ophthalmic lenses to use such optical apparatus as lamps or ambient light to create superficial refraction in order to view engraved markings on progressive lenses or to inspect surface quality of semi-finished or finished ophthalmic lenses using same. Such methods are, however, inefficient because of the lens manipulations that the method requires as well as improper retrieval of markings often due to insufficient lighting and incorrect refraction angles. Manually applied processes cause instability and operator fatigue which are also causes of human error as well as potential permanent degradation of the operator's vision if such an individual is assigned this duty for long periods of time. I have found that these disadvantages may be overcome by providing an integrated instrument incorporating sufficient lighting, reflection angle selection capability and magnified projection capability. Such an apparatus reduces manipulation to the simple placing of the lenses onto the examination surface area. Controls provided for the adjustments of light intensity and selection of refraction angle provide for accuracy and greater stability while examining the lenses. The magnified projection of refracted light offers reduced human eye fatigue and provides better efficiency of the process. In the drawings which illustrate embodiments of the invention, Figure 1 is a side view of the optical assemblies and Figure 2 is a front view of the instrument with all controls. The instrument illustrated comprises a coherent light source (1 ) which is mounted into an optical body (2) toward a collimator (3) and emits light of intensity one to four milliwatts and wavelength 620 to 670 nanometre when activated by the power supply (4). An HeNe lamp may be used as a coherent light source as shown in Figure 1 but a laser diode emitting within the same wavelength may be used if desired. Light emitted through the collimator (3) is directed onto a diffuser (5) which provides for a three inch diameter illumination of the examination surface area (6). The examination surface area (6) is mounted onto a controllable inclination platform (7) which may be inclined in both X and Y axis within a range of + and - 30 degrees using the control lever (8) to provide for the refraction angle β. The diffused light refracted onto the examination surface area (6) is then projected onto a projection area (9). The imperfections and markings which refract light at different angles are seen on the projection area (9) as darker patterns that are very clearly visible. The coherent light source (1 ) intensity may be adjusted using the intensity control (10) to overcome the effect of ambient light. Focus adjustment ( 1 8) may be used to accentuate the sharpness of the projected markings as well as surface imperfections. The adjustment of the refraction angle β is achieved by control motors (1 1 ) located to provide inclination in both X and Y axis through a gear mechanism (1 2). The degree of inclination and its direction within the span of + and - 30 degrees in both axis is obtained by the activation of the control lever (8) in the direction and axis desired. The operation of the control lever (8) is similar to that of a joystick and is directly imputed to the electronic circuit (13). The electronic circuit (13) is used to provide the control motors (1 2) with the required voltage as imputed by means of the control lever. An additional function of the electronic circuit (1 3) is to control the intensity of the coherent light source (1 ) by supplying the necessary voltage as selected by the operator using the intensity switch (14). Selection of light intensity level as displayed on level meter (1 6) is achieved by pressing the light intensity switch (14). Each time the light intensity switch (14) is pressed, the light source (1 ) intensity will increment by a factor of 1 on a scale of 0 to 9. The electronic circuit (13) will output to the coherent light source (1 ) a corresponding power value. The power supply (4) contains a voltage transformer which reduces standard 1 10 AC voltage required to supply the instrument to 5 volts DC required by the electronic circuit (13). Power may be interrupted using switch (1 7). The electronic circuit ( 1 3) contains a self test routine that is initiated on power up of the instrument. The condition of the instrument upon self test is shown on the front panel using "fault and function" LEDs (light emitting diode). As will be appreciated, an instrument as illustrated by Figures 1 and 2 and as described in the specification above has numerous applications throughout the industry of optics for the purpose of inspecting and/or examining lenses at various stages of the making. Examples of such applications are for inspection of surface quality after treatments and coatings, inspection of semi-finished and finished lenses used for telescopes, binoculars and other similar products. SUBSTITUTE SHEET Those skilled in the art will recognise that the embodiments disclosed herein are unique in nature and that various changes can be made therein without departing from the scope and spirit of the invention. In this regard, and as was previously mentioned, the invention is readily embodied with various light source configurations which will provide similar results. Other mechanisms may be applied for producing the necessary refraction angle and magnification all aiming at the same principle described herein. BSTITUTE SHEET

Claims: CLAIMS The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follow: 1 . An instrument for the examination of markings used in the fabrication of ophthalmic lenses comprising: an optical apparatus for generating said refraction of light to produce said projection of markings. 2. The instrument of claim 1 , wherein said optical apparatus is used for generating said refraction of light to produce said projection of surface imperfections of ophthalmic lenses. 3. An optical apparatus for generating said refraction of light for examining ophthalmic lenses comprising: a light source, a collimator and a diffuser for examining said markings and said surface imperfections. 4. The instrument of claim 1 , wherein said optical apparatus for generating said refraction of light comprises: a two axis controllable inclination platform to create said refraction angle β. 5. A method of detecting ophthalmic lens markings and surface imperfections comprising: an optical apparatus for generating said refraction of light to produce said projection onto the said projection area. 6. The instrument of claim 1 , wherein said optical apparatus comprises: a light source and adjustment of same used to enhance said examination of markings and said surface imperfections. 7. The instrument of claim 1 , wherein said optical apparatus comprises: a focus adjustment used to enhance said examination of markings and said surface imperfections. SUBSTITUTE SHEET

Inventors: DORE ROGER, DORE, ROGER
Applicants: DORE ROGER, DORE, ROGER
Application year: 1995
Main classification: G01M11
IPC codes: G01M11