JPH0316005B2 - - Google Patents

Description

REFERENCES TO RELATED APPLICATIONS This application relates to the applications dealing with similar subject matter listed below, all of which are assigned to the same assignee and filed concurrently with the present application. Wunnava V. Subbarao, Richard I. Ely, Carl
USSN 358,825 filed March 16, 1982 in the names of E. Mosier and James E. Andree, ``Flexible Keyboard and Switches,'' filed March 16, 1982 in the names of Richard I. Ely and Wunnava V. Subbarao. USSN 358, filed on
823 “Multi-sided optical thin film switch device” Wunnava V.Subbarao, Richard I.Ely and
USSN 358,824 filed in the name of Carl E. Mosier on March 16, 1982 ``Molded Optical Keyboard with Fiber Optical Keys'' USSN 358 filed in the name of Richard I. Ely on March 16, 1982 , 822 "Single-Sided Optical Thin Film Switch and Keyboard" BACKGROUND OF THE INVENTION 1 Field of the Invention This invention relates to optical/optical switches and keyboards, and more particularly to planar monolithic optical/optical switches and keyboard devices. 2 Description of the Prior Art Fiber optical keyboards and switches are interesting because they reduce the number of light emitting diodes (LEDs) and detectors required, unlike the one-to-one requirements of early light-to-optical keyboards. One LED can illuminate a bunch of fibers, each fiber leading to a separate key on the keyboard. At each key, yet another fiber receives the transmitted light and transmits it to a photodetector. If the key is pressed down, the light is blocked by the key's stem or blade and the detector "senses" the absence of light as an activation signal.
Only one for each row in the keyboard matrix by multiplexing the LEDs and detectors.
LEDs are required and only one detector for each column is required. A problem with fiber optical keyboards is the difficulty of molding and/or assembling all the fibers into a keyboard matrix array. Difficult to automate;
Also, the cost of assembly will likely overwhelm the cost savings from reducing the number of LEDs and detectors. Therefore, the main purpose of this invention is to
The object is to solve these and other problems in a new and hitherto undisclosed manner. Another object of this invention is to overcome assembly problems by avoiding the need or requirement for individual fiber elements or elements. Another object of the invention is to provide a one-piece, molded, integrated optical assembly in the form of a keyboard matrix. SUMMARY OF THE INVENTION An integrated molded monolithic optical assembly comprises a flat planar plastic base member of low refractive index material having a matrix of vertically arranged grooves arranged in rows and columns, the grooves extending from the planar member. The rows are molded into one surface of the member, and the grooves form the columns molded into an opposite parallel plane of the member. This row and column groove is filled with a second high-index type of plastic material, effectively creating a flat rectangular waveguide (rather than the circular type that results from using fiber bundles). . Horizontal rows are formed at the top of the base member and vertical columns are formed at the bottom of the base member. A curved tap is located near the intersection of each row and column, each curved tap having a window or through-opening between its terminal ends. The row taps turn in the direction of the column taps (ie, toward the middle of the intersection), so that light from the horizontal parallel waveguides is transmitted to the vertical column waveguides (ie, from the top to the bottom of the matrix). Light blocking elements or keyblades, such as opaque members, are reciprocally movable within the aperture and alternately block and unblock light to associated photodetectors. To increase the optical coupling between the upper and lower waveguides, the keyboard may be formed from two different plastic materials, one black and one transparent. The transparent part transmits light when it enters the intersection area. The transparent portion reduces the effective optical thickness of the gap between the two waveguides. This is similar to the effect that objects underwater appear closer to the surface than they actually are. Furthermore, yet another increase in optical coupling between the upper and lower waveguides can be created by molding a lens into the keyblade. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic plan view of a structure according to the technique of the present invention. FIG. 1A is a partial cross-sectional view of the circled area in FIG. 1. FIG. Figure 1B is
FIG. 3 is a front view of the device shown in FIG. FIG. 2 is a greatly enlarged portion of the structure of FIG. 1, showing the window between the upper and lower waveguides. Figure 2A shows
Figure 2 shows a detail of one of the curved taps or coupling mechanisms. FIG. 3 is an enlarged detailed side sectional view of the circled portion in FIG. 2. DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus of the present invention provides a unitary, single integrated molded optical assembly, which in the preferred embodiment is shown as a keyboard matrix. As shown in FIG. 1, a single hard piece of clear plastic 10 of generally rectangular or square perimeter having top and bottom surfaces 12 and 14, respectively, is molded and slightly undercut. A plurality of horizontal rows 16 are provided, the rows 16 extending from one outer circumferential edge of the member 10 to the member 1.
A recess or groove is formed in the top surface 18 of the surface 12 that extends a small distance to the outer circumferential edge opposite the 0. A plurality of rows 20 having similarly undercut recesses or grooves 22 are molded into the opposite surface 14. In the intersection area between groove 18 and groove 22 (top and bottom), upper and lower curved taps 24 and 26, respectively, are provided as shown in FIG. 1 and more clearly in FIGS. 1A and 2. is shown. As can be seen in the enlarged view of FIG.
It is bent downward in the direction of opposing upwardly curved taps 26 extending upwardly from the top. At approximately the exact midpoint where the two taps 24 and 26 intersect, a window or aperture 28 is formed in the member 10 and extends into and through the member, as shown most clearly in FIG. The base plate member 10 is formed of a low refractive index material N ₂ and the high refractive index material N ₁ is formed in the grooves 18 and 20.
By molding the light 30 from the light generator 32 into and through the row groove 18, through the tap 24 and across the aperture 28,
into the column groove 22 via the lower tap 26;
is received by optical receivers 34 in the array. Note that the gently curved taps 24 and 26 direct light 30 across the gap with substantially no attenuation. The key structure 36 shown schematically in FIGS. 1A and 3 (in a light passing position) has a transparent light passing portion 40 (or opening 4 as seen in FIG. 1A).
1) and a light blocking portion 42. Key 36 is shown in the depressed position with light passing portion 40 adjacent two facing ends 44 and 46 of upper and lower waveguides 18 and 22, respectively, such that light 30 is transmitted through the aperture. 41
and forms a signal at the optical receiver 34. Releasing the key 36 by a return spring (not shown) forces the light blocking portion 42 into the gap region 28, thereby blocking the light 30 from the optical receiver. The keyblade includes a transparent portion 40 and an opaque or black portion 42. By appropriately selecting the parameters and materials of the aperture 41 and the base 38, the lens 48 of FIG. It is possible to increase the light coupling between the two.

Claims (1)

Claims: 1. A base member made of a photoconductive material having a refractive index N ₂ , the base member including a plurality of light conductive grooves on the front and back sides, the grooves being arranged in an orthogonal array, The vertical grooves on the back side of the member are perpendicular to the horizontal grooves on the front side of the base member, and a pair of vertical grooves are arranged near the intersection of each horizontal groove and the vertical groove and connected to each of the horizontal groove and the vertical groove. further comprising a tap member, wherein the tap connected to the horizontal groove and the tap connected to the vertical groove are formed such that their respective ends face each other; further comprising windows formed in opposing positions and extending into the base member, for blocking light transmitted through each of the pair of taps from the light generating means to the light receiving means to instruct the switch to close. The molded optical waveguide switching device further comprises a light blocking/non-blocking member arranged to move within each of the windows. 2. The base member is a flat member and is molded from a photoconductive material having a refractive index N ₂ .
An apparatus according to claim 1. 3. The apparatus of claim 1, wherein each of the grooves on the front and back surfaces of the base member is molded from a photoconductive material with an index of refraction _N1 , with _N1 > _N2 . 4. The apparatus of claim 1, wherein each of said taps is gently curved from said horizontal surface, and said tap is curved from said vertical surface toward its opposing member. 5. The device of claim 1, wherein the light blocking/non-blocking member comprises a plastic element having an opaque light blocking portion and a light transmitting portion. 6. The molded optical waveguide switching device includes a single unitary planar monolithic structure, wherein the groove and the device are both simultaneously filled and molded to form a switchable light-conducting channel. gives an orthogonal array,
An apparatus according to claim 1. 7. The apparatus of claim 1, wherein said light blocking/non-blocking member further includes lens means to increase said light coupling between adjacent taps to effectively increase light output.