Patent Application
20150286075
The present invention relates to a machine which determines ophthalmic frame groove dimensions in up to three axes of a metal or plastic optical frame so that a ophthalmic lens can be cut with a precise bevel allowing the lenses to individually fit inside the eye wire with their optical centers aligned to a user's pupil positions with minimal frame distortion.
Existing techniques to measure eyeglass frame dimensions employ a mechanical stylus. See, for example, US20140020254, US20130067754, and U.S. Pat. No. 8,578,617, which all describe mechanical contact methods to measure the shape and dimensions of the frame needed to fit the glass. These patents describe measuring the groove of the frame to get information about the shape and dimensions of the frame which assists an eyeglass maker to decide on the dimensions to cut a lens and its bevel to fit a frame.
The problems with these methods include:
The present invention eliminates a physical stylus tracing the lens shape by using an imaging system to create a computer model, and then using that model to determine how a lens should be best cut to fit the frame.
A computer model of an eyeglass frame lens groove is created in a two-stage process, which is then used to manufacture the lenses. A microscopic camera is used to track a frame's lens groove and provide data for the computer frame model. A lighting system is designed specifically to assist the camera to create images which the programmed computer can use to find frame and groove contour lines.
For a better understanding of the disclosure, and to show by way of example how the same may be carried into effect, reference is now made to the detailed description along with the accompanying figures in which corresponding numerals in the different figures refer to corresponding parts.
While the making and using of various embodiments of the present disclosure are discussed in detail below, it should be appreciated that the present disclosure provides many applicable inventive concepts, which can be embodied in a wide variety of specific contexts. The disclosure is primarily described and illustrated hereinafter in conjunction with various embodiments of the presently—described systems and methods. The specific embodiments discussed herein are, however, merely illustrative of specific ways to make and use the disclosure and do not limit the scope of the disclosure.
Two measurement methods are disclosed in the present invention: (1) an Imaging Method; (2) a Mechanical Touch Probe Method. In both of these methods, a computer model of an eyeglass frame lens groove is created in a two-stage process, which is then used to manufacture the lenses. The two methods differ only in their first stage, in which the initial data to drive a microscopic camera is collected.
These methods capture multiple images from the interior of an eyeglass lens grove; the computer processes the images to identify, measure and store the features of the frame's lens groove. In the current embodiment, a user removes a lens from the left side of the frames to allow for the frame groove can be measured and modeled. This method can be used to generate a standalone three-dimensional model generation of the lens that is cut and beveled.
The Imaging Method uses a Z-Axis Laser 25 to determine the vertical dimension (z-axis) of the top of a Frame 11 as it is mounted in the invention, as it creates a computer model of the Frame 11 and designs the lens to properly fit the Frame 11.
The Mechanical Touch Probe method uses a Touch Probe to find the vertical dimension, rather than a camera and laser, to correct the computer model for the frame's curvature,
The objective of the invention is to characterize the precise shape of a pair of eyeglass frames, including that of the internal groove (see
The imaging system based method is performed in two stages. The first stage measures the dimensions of a pair of glasses. The second stage focuses on the frame's inside grooves in which a lens fits and is held in place. Together, these processes produce a data set sufficient to cut the real lens and form the proper bevel on its edge.
One embodiment of the first stage is the Imaging System, shown on
In the Frame Measurement stage of the Imaging Method, the eyeglass Frame 11 is positioned by small steps in the x-y plane with a computer-controlled linear X-Y Stage 33, as shown in
In the current embodiment, the algorithm overlays places two lines horizontally across the lens locations on the Macro-Image 19, and two vertically over both lens areas. The algorithm determines the x- and y-coordinates of points close to the boundary of the Frame lens. In this embodiment, this process creates eight sets of coordinates, called Frame Points 23.
The Camera 13 is then placed in a position close to the frame to capture Micro-Images 19 in front of each Frame Point, as shown in
These Micro-Images 19 are recorded, and any mismatch between expected coordinates is used to correct initially collected coordinate data. The Frame Groove 27 is thereby tracked in real time as the Camera sweeps in a full circle, tracking the Groove 27 during the sweep, and collecting its modeling data.
The Micro-Images 19 are taken at a constant distance from the Frame 12 and lens. This is necessary to keep the pixel scale the same in each Micro-Image 19. The constant distance is maintained by Z-Axis Stage 35. Its data may be supplied either by the Mechanical Touch Probe Method, shown in
By applying established and proprietary image processing algorithms, the exact coordinates of points on the boundary of the Frame 11 and Lens 21 may be determined to better than one-micron accuracy in any dimension.
For the Groove Measurement (stage 2), the Camera 13 must have miniature imaging capability system.
This imaging system is rotated with the frame in series of steps. A series of Micro-Images, close-up photos, is taken over a full 360 degrees. The steps can be as little as two microns, depending on the precision of the encoders used on each positioning stage
The Micro-Images are processed to determine the thickness of the groove and its path in the x-y plane. This process also gives the z-axis data with respect to the frame scan in stage one.
As shown in
To initiate the Mechanical Touch-Probe Method, the eyeglass frames are mounted on a high-accuracy X-Y Stage 33. The probe is mounted on a Z-Axis Stage 35.
The Frame Point 23 position data from the Imaging Method (described above) is used to position the probe. The probe samples the depth of the frame at each of the strategic Frame Points 23. These measurements characterize the profile of the Frame 11.
The method disclosed assumes that the invention's user has no access to factory construction data of the eyeglass Frames 11. However, if this data is available, then it provides significant data to begin a successful model, including the ‘A’ and ‘B’ industry dimensions of lens height and depth.
The current embodiment of the method described is typically performed on the left lens, and a dummy lens is kept in the right lens Frame Groove 27. This allows the user to detect if a dummy lens 27 is missized or misshapen by comparing the examination results of the method on the left side of the frame with the expected shape found on the right, during the first stage of the process, using the Macro-Image.
The current invention also uses a color and intensity controllable light array with multiple independent zones to improve contrast, front and back lighting in the area of interest, when different types of frame materials, like metal, plastic, transparent plastic, translucent plastic or rimless frames are measured in the same apparatus. This allows easy detection of edges and groves under a variety of material conditions.
