OPTICAL DISPLAY DEVICE

Abstract: An optical display device employs liquid crystal light gates (58) associated with illumination means (54) selectively to pass or block radiation therefrom under the control of control means (60) in accordance with a desired pattern. Light transmitted by selected gates (58) is applied to corresponding optical fibers (62) which at their end form a display (50). Multiple displays (50, 52) may be achieved by providing a plurality of optical fibers (62) extending from each gate to several displays on which identical information is displayed. The device uses lower voltage and current than comparable displays and is inexpensive to manufacture.

Description: OPTICAL DISPLAY DEVICE Technical Field This invention relates to optical display devices for displaying numeric, symbolic and other information in response to operator or machine inputs to electronic selection and addressing circuitry. More particularly, this invention relates to an optical display device suitable for use in various types of business machines, especially those in which it is desired to provide more than one display for displaying identical information as for example a point-of-sale terminal having a first display positioned for reading by the customer and a second display readable by the operator. Background Art Devices for displaying numerical and symbolic information find wide usage in many types of business equipment. Three important considerations involved in the determination of the type of display to be employed are display intensity, cost and power requirements. One type of well-known and widely-used display device is the cathode ray tube. This display provides excellent light intensity, but is relatively heavy, complex, and expensive, and has relatively high power requirements. Other types of displays, such as vacuum fluorescent displays and plasma displays, have relatively high voltage and current requirements. The above considerations become even more important in those cases in which more than one display is required for a single terminal. Disclosure of Invention It is an object of the present invention to provide an optical display device of relatively high intensity having relatively low voltage requirements and being readily adaptable for multiple displays of the same information. Thus, according to the invention, there is provided an optical display device in which light is transmitted from illumination means to an optical display screen, characterized by the combination of a plurality of radiation gates operatively associated with said illumination means selectively to pass or block the radiation therefrom; control means for individually controlling each of said radiation gates in accordance with a desired display pattern; and a plurality of fiber optical elements, at least one being optically coupled at one end to each radiation gate; said optical display screen embodying the other ends of each of said fiber optical elements, whereby radiation generated by said illumination means is selectively passed by said radiation gates under control of said control means and transmitted by said fiber optical elements to said optical display screen to provide a visible pattern therein in accordance with the control exercised by said control means. Brief Description of the Drawings Embodiments of- the invention will now be described, by way of example, with reference to the accompanying drawings in which: Fig. 1 is a diagrammatic view of one illustrated embodiment of the optical display device of the present invention in which a single display screen is employed. Fig. 2 is a diagrammatic view of a second illustrated embodiment of the optical display device of the present invention in which two display screens are employed. Fig. 3 is a perspective view of the embodiment of the optical display device shown in Fig. 2. Fig. 4 is a diagrammatic view showing the matter in which the radiation gates of the present invention are controlled. Fig. 5 is a fragmentary view of an embodiment of the optical display device of the present invention in which a bar code display is employed. Fig. 6 is a diagrammatic view of one form of optical gate device which may be employed in the optical display device of the present invention. Fig. 7 is a fragmentary sectional view of the optical gate device of Fig. 6, taken along line 7-7 of Fig. 6. Best Mode for Carrying Out the Invention Referring now to Fig. 1, one embodiment of the optical display device of the present invention is shown in diagrammatic form, and is controlled by display input logic circuitry represented by block 10, which will subsequently by described in greater detail. The display input logic 10 is electrically coupled, over conductors such as conductor 12, to a plurality of individual optical gates 14, one for each individual optical element contained in the display. The visible light or other radiation which is gated by the gates 14 emanates from a source 16, which may take the form, for example, for each gate, of an individual incandescent light bulb, or which may take the form of a single large source of illumination, which can be suitably diffused with a diffuser or spread by a suitable reflecting surface, to extend to all of the gates 14. This radiation, which will subsequently be referred to as "light" in the interest of simplicity of description, may be selectively blocked or transmitted by the gates 14, as will subsequently be described in greater detail. In the embodiment shown in Fig. 1, a single fiber optic element 20, or bundle thereof, is associated with each optical gate 14, so that when the gate 14 is "open", the illumination from source 16 passes unimpeded through said gate.to the associated fiber optic element 20, and is transmitted thereby to its destination which, in this embodiment, is an end surface 22 of the optic element 20 which is incorporated in a screen 24. Since the light passing through the gate 14 is transmitted with minimum diffusion by the fiber optic element 20, there is little light loss, even though there may be a considerable distance between the gate 14 and the end surface 22 in the screen 24. It will be noted that only one row of fiber optic elements 20 is shown as connected to the screen 24, in order to avoid undue complication and interference of elements in the showing of Fig. 1. However every end element 22 of the screen 24 will have a fiber optic element. 20.associated therewith, and every element 20 will be optically coupled to a gate 14 for selectively passing or blocking, under control of the logic circuitry 10, light which has originated at the source 16. Any suitable type of gate 14 may be employed for control of transmission of light from the source 16 to the associated fiber optic element 20. One suitable type is shown diagrammatically in Figs. 6 and 7 , and employs a liquid crystal device in a sandwich configuration. A liquid crystal material 34 is centrally located in the gate structure and is retained in position by two transparent plates 26 and 28 of glass or other suitable material. The plates 26 and 28 are sealed around their edges to prevent escape of the liquid crystal material 34. On the outer sides of the plates 26 and 28 are positioned polarizing elements 18 and 19, with the direction of polarization of one being oriented at an angle, typically perpendicular, to the other. Electrodes 30 and 32 are located on the outer surfaces of the polarizing elements 18 and 19 and are disposed at right angles to each other in an "X" "Y" configuration to permit coordinate selection of a given incremental liquid crystal area by applying suitable potential across the selected "X" and "Y" electrodes. Terminals 31 and 33 are connected to the electrodes 30 and 32, respectively, to enable these electrodes to be connected to the display input logic circuitry 10. The illustrated embodiment of the gate 14 is of the "field effect LCD" type. Light from the source 16 is polarized in one direction by the polarizing element 18 or 19 adjacent thereto. As the polarized light passes through the liquid crystal layer 34 it is twisted or rotated by some angle, say ninety degrees, by action of the liquid crystal, so that as it emerges from the liquid crystal, it is aligned directionally with the other one of the polarizing elements 18 or 19, and is permitted to emerge from the gate 14 and pass to the associated fiber optic element 20, which transmits said light to the screen 24. Coordinate selection by the display input logic 10 of a particular incremental area of the gate 14 by application of appropriate potential to the electrodes 30 and 32 which intersect across said area causes the liquid crystal layer 34 of that area to be disoriented, thereby blocking transmission of light therethrough. As noted above, field-effect LCDs are voltage-operated devices, as distinguished from other types, such as the dynamic-scattering type, which are current-operated. Field-effect LCDs require a lower voltage threshold than do the materials in dynamic- scattering types of devices. They also usually have a longer total display life because the LCD material used therein does not contain deliberately added impurities to provide a means for current flow, as is true with the dynamic scattering types of devices. One arrangement for controlling the gates 14 of the display device is shown in Fig. 4, in which a coordinate selection scheme is employed. The input which a user desires to display is applied by an input 40, such as a keyboard, or an interface from another terminal, to a suitably programmed microprocessor 42. The micro-processor 42 accesses a storage unit which may take the form of a read-only memory or ROM 44 to ascertain the correct gate pattern data for the input information which is to be displayed. The pattern data is transferred from the storage unit 44 to the microprocessor 42, which controls coordinate drivers 46 and 48 to sequentially energize appropriate horizontally and vertically oriented and aligned (or "X" and "Y") electrodes 30 and 32, to cause incremental gate areas 14 defined by the intersections of the electrodes to open, thereby permitting light from the sources 16 to pass through the selected gates 14, and be transmitted by the fiber optic elements 20 to the display screen 24. Sequential energization of the selected electrodes is repeated at intervals of a frequency and duration suitable to cause the display appearing on the screen 24 to appear continuous, through the well-known phenomenon of persistence of vision. Shown in Figs. 2 and 3 is a second embodiment of the present invention, which is similar to the first embodiment of Fig. 1, except that a plurality of display screens 50 and 52 are employed. This embodiment is useful, for example, in applications, such as point-of-sale terminals, in which two identical displays are desired, one for viewing by a customer purchasing items such as groceries, and one for the check-out operator or cashier. The same arrangement as was described in connection with the embodiment of Fig. 1 is employed here for determining the numbers, symbols or other indicia to be displayed. The arrangement includes illumination sources 54, a plurality of optical gates 58 in a support 59 and logic circuitry 60. As described in connection with the embodiment of Fig. 1, the logic circuitry may include an input, a microprocessor, a storage unit and "X" and "Y" drivers. These individual elements have the same arrangement and relationship as shown in Fig. 4, and that showing will therefore not be repeated. Transmission of the light generated by the sources 54, which is selectively gated by the gates 58, to the display screens 50 and 52, is accomplished by the use of two fiber optic elements, or bundles of elements 62 in association with each gate 58. One element 62 extends from the gate 58 to the screen 50, and the other element 62 extends from the gate 58 to the screen 52. One end of each pair of fiber optic elements 62 associated with a given gate 58 is positioned in a retainer 64, by means of which it. is maintained in operative relationship with its associated gate 58. Light passing through a selected gate 58 is thus directed to an equal extent to one end of each fiber optic element 62 of the pair, and is transmitted by the paired elements 62 to the screens 50 and 52. As mentioned earlier, the display screens such as 24, 50 and 52 may take a variety of forms. The form shown in Figs 1, 2 and 3 has the advantage of providing a great deal of versatility in the shape and size of numbers, symbols and other indicia displayed, due to the fact that the display essentially is made up of a large number of dots, which can be combined in a great variety of ways as is well-known, for example, in recording done by a dot matrix printer. A corresponding disadvantage of this type of display is that a large number of optical shutters or gates are required, essentially one for each dot of the display, which complicates the electronic logic addressing the gates, and requires a large number of fiber optic elements. An alternative type of display is shown in Fig. 5, and consists of a screen 63 which includes therein a plurality of seven-bar code devices 65, each comprising seven elements 66, each of which is connected to an end of a fiber optic element 68. The other end of each fiber optic element 68 is operatively associated with an optical gate, such as the gates 14 of Fig. 1 or the gates 58 of Figs. 2 and 3. Each of the elements 66 comprises a diffusion cap for its associated fiber optic element 68, so that the light transmitted by the element 68 is applied to and diffused along the element 66, thus illuminating the entire element. Since only seven such elements are required to comprise an entire character, it will be seen that relatively few fiber optic elements 62 and associated gates, illumination sources, and electroni-c. addressing circuits are required to provide a complete display, compared to the number of such components which are required to constitute a complete display of the type shown in Figs. 1, 2 and 3. On the other hand, this arrangement lacks the versatility of the screens of Figs. 1, 2 and 3 in permitting the formation of characters of varying size and non- standard configuration.

Claims: CLAIMS 1. An optical display device in which light is transmitted from illumination means (16, 54) to an optical display screen (24, 50), characterized by the combination of a plurality of radiation gates (14, 58) operatively associated with said illumination means (16, 54) selectively to pass or block the radiation therefrom; control means (10, 60) for individually controlling each of said radiation gates (14, 58) in accordance with a desired display pattern; and a plurality of fiber optical elements (20, 62), at least one being optically coupled at one end to each radiation gate (14, 58); said optical display screen (24, 50) embodying the other ends of each of said fiber optical elements (20, 62), whereby radiation generated by said illumination means (16, 54) is selectively passed by said radiation gates (14,'- 58) * * under control of said control means (10, 60) and transmitted by said fiber optical elements (20, 62) to said optical display screen (24, 50) to provide a visible pattern therein in accordance with the control exercised by said control means (10, 60). 2. Display device according to claim 1, characterized in that said plurality of radiation gates (14, 58) include first polarizing means (18) for polarizing the radiation from said illumination means (16, 54) in a first direction, shutter means (34) selectively operable to rotate light from said first direction to a second direction, and second polarizing means (19) for transmitting only radiation polarized in said second direction. 3. Display device according to claim 2, characterized in that said shutter means (34) is a liquid crystal device. 4. Display device according to claim 3, characterized in that said shutter means (34) is comprised of a coordinate matrix of incremental shutter areas, each representing a radiation gate (14, 58) and being optically coupled with at least one fiber optical element (20, 62). 5. Display device according to claim 4, characterized by electrodes (30, 32) extending perpendicularly to each other on opposite sides of said matrix of shutter areas (34), said electrodes (30, 32) being selectively energizable to cause a liquid crystal area defined by the intersection thereof to change state, to block radiation directed thereto. 6. Display device according to claim 1, characterized in that said plurality of radiation gates (14, 58) comprise individual radiation gates (14, 58) arranged in a coordinate matrix. 7. Display device according to either claim 4 or 6, characterized in that said control means (10, 60) for individually controlling each of said radiation gates (14, 58) includes vertical address control means (48) and horizontal address control means (46) for operation of selected radiation gates (14, 58); display control means (42) for controlling the vertical and horizontal address control means (48, 46); input means (40) for selecting the symbols to be displayed; and storage means (44) containing symbol patterns to be selected by said input means (40) and entered into said display control means (42). 8. Display device according to claim 1, characterized in that said illumination means includes individual incandescent elements (16, 54) equal in number to, and operatively associated with, corresponding radiation gates (14, 58). 9. Display device according to claim 1, characterized in that said optical display screen (64) includes a plurality of bar code elements (66), each of which is coupled to at least one fiber optical element (68), whereby a display of a series of symbols defined by sets of bar code elements (66) is provided. 10. Display device according to claim 1, characterized by a second optical display screen (52), and having at least one fiber optical element (62) extending from each radiation gate (58) to each of said optical display screens (50, 52), whereby identical patterns are provided on each display screen • (50, 52) In accordance with the control exercised by said control means (60).

Inventors: MEYERS THOMAS J, MEYERS, THOMAS, J.
Applicants: NCR CO, NCR CORPORATION
Application year: 1986
Main classification: G09F9
IPC codes: G09F9