Split optics arrangement for vision inspection/sorter module

• US 6,188,784 B1
• Filed: 03/03/1998
• Issued: 02/13/2001
• Est. Priority Date: 07/12/1996
• Status: Expired due to Fees

• Current Assignee: American Tech Manufacturing Corporation
• Original Assignee: American Tech Manufacturing Corporation
• Inventors: Linker, Frank V. Jr.
• Primary Examiner(s): MEHTA, BHAVESH M
• Application Number:
  US09/029,685
• Time in Patent Office: 1,078 Days
• Field of Search: 382/145-146, 731/04, 348/126, 348/87, 348/92, 348/94, 348/95, 348/131, 348/135, 359/462, 359/463, 356/237, 356/237.1, 250/559.34
• US Class Current: 382/146
• CPC Class Codes: G01B 11/14 for measuring distance or clearance between spaced objects or spaced apertures G01B11/26 takes precedence; rangefinders G01C3/00
• CPC Class Codes: G01N 21/95684 Patterns showing highly reflecting parts, e.g. metallic elements

Abstract

The present invention provides method and apparatus for determining lead integrity of IC devices characterized by an inspection arrangement which comprises optical elements for back lighting the leads disposed on either side of a trackway for the travel of the IC device thereon. The optical elements are arranged in such a fashion as to simultaneously produce a sharp backlit silhouette image of the leads protruding from either or both sides of the IC device. In accordance with the invention, means are provided for continuously and automatically feeding IC devices through an inspection station in the apparatus where an illumination source through the optical elements directs an intense light beam so that a sharp silhouette or backlit outline of the leads on both sides of the IC device is simultaneously obtained. A single camera is disposed to face the opposing direction of the illumination and optics to receive the silhouette or backlit outline of the IC device leads, as well as the top surface of the device. Electrical signals responsive to the camera image generate an output signal of lead dimensional characteristics. A computational means compares the output signal of lead dimensional characteristics to predetermined acceptable tolerances. A signal responsive to the computational means determines whether the IC device is accepted, rejected, or shunted to a repair station.

Claims

1. In a method of determining lead integrity of IC devices having leads, comprising the steps of:

providing illumination of the leads;

producing a back lit outline of at least one side of the IC device to create a silhouette of the leads;

simultaneously recording the image of three orthogonal views of the IC device leads with a single camera.

2. The method of claim 1 wherein both sides of said device are backlit simultaneously.

3. The method of claim 1 further comprising the step of recording the image of the top of the device with the single camera.

6. Apparatus in accordance with claim 1 wherein the prism is laterally adjustable to inspect IC devices of varying widths.

4. Apparatus for inspecting the leads of an IC device by illuminating the leads and recording the image thereof with a camera, converting the recorded image into an electrical signal and determining the integrity of leads based upon said electrical signal, wherein the improvement comprises:

means for illuminating said IC devices;

an optical arrangement operable to simultaneously record images of said IC device in three orthogonal directions;

means for recording said images with a single camera;

means for converting said images into electrical signals;

means for comparing said electrical signals with stored dimensional standards.

5. Apparatus for inspecting the leads of an IC device by illuminating the leads and recording the image thereof with a camera, converting the recorded image into an electrical signal and determining the integrity of leads based upon said electrical signal, wherein the improvement comprises:

at least one diffusion prism disposed beneath the IC device which creates a backlit image of the leads comprising light transmitted directly to the camera and light reflected by a mirror set at an angle which directs back lit image light from the at least one diffusion prism toward the camera, whereby images of the IC device leads are simultaneously recorded in three orthogonal direction.

7. Apparatus is claimed in claim 5, including two diffusion prisms disposed beneath the IC device which creates a backlit image of the leads on one side of the device comprising light transmitted directly to the camera and light reflected by two mirrors, each set at an angle which directs back lit image light from the diffusion prisms toward the camera.

8. Apparatus is claimed in claim 5, including at least one optical prism assembly disposed beneath the IC device which creates a backlit image of the leads on one side of the device and which directs the light from the backside of the leads toward the camera.

9. Apparatus is claimed in claim 5, including two optical prism assemblies disposed beneath the IC device, each of which creates a backlit image of the leads on both sides of the device and which direct the light from the backside of the leads toward the camera.