Minnesota Mining and Manufacturing Company

James K Kennedy

James A Wilson

Michael C Sweaton

Gary L Tritle

Dwight G Baldwin

Steven G Saxe

Peter G Burton

A card reader which doubles as a carrying case for storing a stack of preview cards used in an electronic presentation. The card reader case has a flat, rectangular body housing the reader components, and a cover hingedly attached to the body, the cover having a pocket therein for storing the cards. The cover is attached in such a manner that the topmost of the stored cards is visible when the cover is in the open position. In this position, the lower end of the cover also serves to support and elevate one end of the body. The body further has a slot therein on its upper surface for retaining one of the cards for optical scanning, the scanned card extending away from the upper surface so as to be visible to the user during scanning. A discard area may also be formed on the upper surface of the body, and a light source may be positioned on the upper surface to illuminate any card retained in the slot. If the card reader utilized a remote (wireless) interface, the interface may be attached to the upper portion of the cover so that the interface is raised above other objects on the support surface when the device is in use.

Card reader case

An apparatus for reading an optical bar code on a transparent film uses a linear array of light sources and a linear, solid-state sensor located parallel with array. LED's are energized selectively in groups to avoid overlapping shadows on the sensor. A novel algorithm is used to reconstruct the shadowgraphs or image segments by searching for a transition (mark/space edge in the bar code) in an overlap zone at the boundary of adjacent segments on the sensor. Conventional techniques are then used to decode the reconstructed electronic image of the bar code. The apparatus is particularly useful in an electronic presentation system wherein the numeric value of the bar code is an image reference number (IRN) which is used to access a host computer and display a graphic image associated with the IRN. A novel bi-directional protocol is also presented for providing communications between the optical reader and the host computer. The protocol directs the host computer to download all IRN's for a given presentation to the reader. The reader can then locally determine if a bar code on a card corresponds to a valid IRN in the current presentation. The protocol may be adapted to download certain display control information and send associated control signals to the host computer based on keyboard input at the reader.

Solid state optical reader with bi-directional protocol

Combined card reader and case

A presentation system uses a computer to store and transmit electronic images to a liquid crystal display (LCD) panel which rests on an overhead projector. The LCD panel includes a calibration circuit designed to correct discrepancies in the saturation levels of the three primary colors. The calibration circuit determines the digital values in a signal corresponding to a test pattern of maximum intensity for all three colors, and compares these values to predetermined theoretical values. The differences between these values are recorded as calibration constants and are used to correct the image signals transmitted from the computer. A remote control unit may be used to provide a stimulus to both the computer (to generate the test pattern) and the LCD panel (to execute the calibration process).

Color calibration for LCD panel

An overhead projector (OHP) presentation system uses a liquid crystal display (LCD) panel to project electronically stored graphic images. The OHP preferably includes an integrated computer having a plurality of output ports for connection to various peripheral devices. A novel interface card is also used to provide electrical connections between the computer and the LCD panel, providing the further benefit of aligning the transmissive portion of the panel with the stage of the OHP. The LCD panel may be designed to swing horizontally into the optical path. This may be accomplished by providing a sliding drawer which inserts the panel within the body of the OHP, or by pivotally attaching the panel to the stage of the OHP.

Overhead projector for LCD panel

An overhead projector (OHP) presentation system uses a liquid crystal display (LCD) panel to project electronically stored graphic images. The OHP preferably includes an integrated computer having a plurality of output ports for connection to various peripheral devices. A novel interface card is also used to provide electrical connections between the computer and the LCD panel, providing the further benefit of aligning the transmissive portion of the panel with the stage of the overhead projector.

Telephone trunk line testing circuitry for connection to a private branch exchange (PBX) and the telephone trunk lines for the PBX including a microcomputer unit (MCU), switching circuitry, a DTMF receiver, and a tone generator for connecting one of the trunk lines as a control trunk for the circuitry. Under the control of the MCU programmed to respond to DTMF various signal commands sent from a telephone at the far end of the control trunk the circuitry operates to selectively disconnect (isolating) one of the other trunks at a time from the PBX and connect it to the circuitry with the circuitry configured under control of the MCU for completing various test involving the trunk under test (TUT), control trunk, switching circuitry and the tone generator, including the supply of tone signals from the tone generator during some of the test configurations.

Growing community of inventors

Round Rock, TX, United States of America

James K Kennedy