JPH048888B2 - - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optical keyboards, and more particularly to optical keyboards having a conventional optical transmission member formed therein which can be easily fabricated into a keyboard. .

BACKGROUND OF THE INVENTION Conventional optical keyboards consist of a key matrix arranged such that a downward press on any key blocks the passage of light transmitted between a light source and a light sensor. Since the keys are arranged in a matrix, there is generally a light source and a light sensor for each row and column. A check of both the row sensor and the column sensor is made to indicate the identity of the pressed key. Although such keyboards correctly display properly pressed keys, they do not provide the N key rollover feature described below. When two or more keys in the same row or column are pressed simultaneously, the ability of the system to identify these pressed keys is referred to as the N-key rollover function. below,
Such a function is called a key rollover function. These types of keyboards can be easily assembled from molded parts of conventional optical transmission materials, which provide manufacturing advantages.

U.S. Pat. No. 3,856,127 discloses a matrix keyboard device in FIGS. 7 and 8 thereof having a light source associated with each row of keys and a light sensor associated with each column of keys. Bundles of individual optical fibers are arranged to emanate from each light source and are arranged transversely along rows with individual fibers in each bundle terminating at different row locations adjacent to the switch isolation device.

A second bundle of optical fibers emanates from each sensor;
traversing along each row with the individual fibers of each bundle terminating at different row locations adjacent to the switch breakers. The light sources in a row are sequentially activated and the light sources in the row associated with that switch are activated through the optical fibers in the adjacent column by actuation of any switch disconnection device having adjacent optical fibers directed from the activated light source. Light transmitted to the sensor is blocked. Accordingly, multiple switches in the same row are actuated to provide multiple indications of key presses to the corresponding column sensors. Additionally, multiple simultaneous presses of keys in the same row provide timed sequential output signals to the sensors in the same column, thereby indicating all keys pressed. Therefore, this keyboard has N key rollover capability. however,
This keyboard requires that the optical fibers in each column be precisely aligned with the optical fibers in each corresponding row so that key actuation will block light.
The assembly becomes very complicated. Additionally, each fiber must be properly positioned relative to the light source and sensor. Furthermore, the fibers must be properly secured to the machine frame to prevent the fibers placed in critical positions from being displaced by machine vibrations. Therefore, the keyboard is difficult to assemble and maintain in proper working order.

DISCLOSURE OF THE INVENTION It is an object of the present invention to overcome the above-mentioned drawbacks of the prior art and to have a key rollover function that allows identification of two or more keys in the same row or column when they are pressed simultaneously. An object of the present invention is to provide an optical keyboard device.

To obtain a molded optical keyboard with N key rollover capability, the keyboard of the present invention incorporates two uniquely shaped light transmission members that can be easily folded together to form a keyboard detection assembly. We are prepared. The light transmission member transmits light along an optical transmission path such that the light is transmitted from a light source along a common column optical transmission path to various row optical transmission paths and then along a common row optical transmission path to a sensor. It forms a reflective surface for bending. Another molded assembly supporting the key actuation portion is provided to the detection assembly, thereby eliminating the need to individually define and align each optical transmission path. This latter assembly is also molded with one of the photoconductive members.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a partially assembled keyboard assembly 1 constructed in accordance with the present invention
A perspective view of 1 is shown. This keyboard assembly 11 includes first optical transmission members 13a, 13
b, 13c, a second light transmission member 15, a key actuation assembly 17, and a plurality of light source assemblies 19.
and a plurality of sensor assemblies 21.

The key actuation assembly 17 includes a support plate 23;
It includes a key button 25 (25a to 25c), a key stem 27, a blocking device 29 and a spring 31. The key button 25 is pressed by the spring 3
1 is compressed, and the key stem is attached to the support plate 23.
is moved downwardly through the light path, moving the blocking device 29 to the optical path blocking position. The groove 33 formed in the second light transmitting member 15 allows the blocking device 29 to be lowered mechanically to block out all light without reaching the bottom.

Emitted from an activated light source 37 on a plurality of light source assemblies 19 and a plurality of sensor assemblies 2
A ray 35 of the light beam 36 reaching a sensor 39 on the sensor 1 shows the optical path that such a ray 35 would travel if it were not interrupted by the blocking device 29. The light source 37 may be a conventional light emitting diode with a predetermined luminous flux distribution associated therewith. The end surface 41 of the material 13c is used for the first light transmission member 13 to slightly converge the energy from the light source 37.
It is shaped like a circular lens for redirection along c. When the light beam 36 traverses the lower part of the first light transmission member 13c, it bends or reflects a portion of the light beam downwards through the surfaces 43a-43.
I hit c. A surface 43 is formed within each first light transmission member 13a-13c for each row of keys. The area of each surface 43 of the first optical transmission member 13c is different from that of the other surfaces 43. The area of each surface 43 is the area of the light beam 36 within the first light transmission member 13c.
is designed so that the downwardly bent light energy is equal for each division. Since the surface 43a is closer to the light source 37 than the surface 43e, the area of the surface 43a is smaller than that of the surface 43e. Therefore,
The area of surfaces 43a to 43e is determined by their associated light source 37.
is inversely proportional to the distance from

Second surfaces 45a to 4 of first optical transmission member 13c
5e is used to redirect the light beam 36 to the right in a direction that appears approximately orthogonal or perpendicular to its initial direction of travel. When so directed, the split light beam 36 is directed in the general direction of the plurality of sensor assemblies 21 .

The first optical transmission members 13a to 13c are made of acrylic.
Made from a transparent plastic material such as plastic. A large part of the light flux entering the first light transmission member remains therein due to the phenomenon of total internal reflection. Surfaces 43 and 45 are designed to have a surface area large enough to reflect all of the light energy by total internal reflection so as to redirect the light energy. Once the light beam 36
When reflected from the first light transmitting member 1
3c and if not blocked by the blocking device 29, the paired 49a to 49e
and enters the second optical transmission member 15. Surfaces 47a-47
e and each of 49a-49e are designed as a pair to minimize light leakage and maximize light transmission. The second light transmitting member 15 is also formed from a transparent plastic material such as acrylic plastic.

Light entering the second light transmitting member through surfaces 49a-49e is reflected by the design of surfaces 47 and 49 using total internal reflection or refraction from surfaces 51a-51e to surfaces 53 and 55. Surfaces 53 and 55 are used to confine light to specific parts of second light transmitting member 15. Ray 35 shows that light is directed onto the active elements of sensor 39 from surface 57e. Surface 57e is designed to focus onto optical sensor 39.

As illustrated, a plurality of first optical transmission members 13
There are a, 13b, and 13c, which are keyboard/
There is one light transmission member for each row of assembly 11. Furthermore, the second light transmission member 15 is divided by grooves 61 to designate different rows through which light is transmitted. The first light transmission member 13 is a support plate 23
The second light transmitting member 15 is formed as a single piece without the groove 61 or as a plurality of pieces divided as indicated by the groove 61.

Referring to FIG. 2, a side cross-sectional view of a portion of keyboard assembly 11 is shown. As shown, when the key button 25 is pressed, the shutoff device 29
blocks the optical path between the surface 47 of the first optical transmission member 13 and the surface 49 of the second optical transmission member 15.

Referring to FIGS. 3, 4, and 5, a plan view, a side view, and an end view of the first optical transmission member 13c are shown, respectively. In this particular description, the first
The light transmitting member 13c is formed from two parts 71 and 73 and another lens and surface 41. Portion 73 is shaped to include surfaces 43a, 43b, 43d, while portion 71 has surfaces 43e, 43c. These figures show surfaces 43 and 47 with different dimensions.

6 and 7 are a side view and an end view of a portion of the second optical transmission member 15. FIG. As shown, the second light transmission member 15 is a single piece and has a groove 61'.
Surface 49d and surface 49e are shown with the same dimensions. Surfaces 49d and 49e are formed corresponding to each surface of surface 47 in FIG. Additionally, groove 61' may be removed.

Referring again to FIG. 1, the operation of keyboard assembly 11 will be described. Light sources 81, 83, 37 are activated sequentially, one at a time. For example, when the light source 37 is activated, only the first light transmission member 13c receives light from one light source on the plurality of light source assemblies 19. As this light is reflected as described above, the light is emitted simultaneously through all of the surfaces 47a-47e and transmitted through the second light transmitting member 15 to the sensors 39, 85-88 in the plurality of sensor assemblies 21. Therefore, the light is received at the same time.
Such simultaneous reception by sensors on the plurality of sensor assemblies 21 indicates that the key associated with the light transmitted through the first light transmitting member 13c was not pressed.

When the light source 83 is turned on, the first light transmission member 1
The light beam transmitted through 3 is transmitted through surfaces 91a-91
Similarly occurs from e. However, the surface 91e
The light emitted from the second light transmitting member 15 is prevented from entering the second light transmitting member 15 by the blocking device 29 . Therefore, sensor 39 does not detect the presence of light from light source 83. Since the logic device understands that the light source 83 was activated and the sensor 39 was unable to detect light during the activation period of the light source 83, it is quite clear that the logic device can detect that the key button 25a has been pressed. That's true.

This logic unit can detect simultaneous key pressesN
Key rollover is provided. For example, if the key button 25b is pressed at the same time as the key button 25a, the light emitted from the light source 83 will not reach the sensor 85. Since both sensors 39 and 85 cannot detect light from light source 83 during their activation time, the logic can indicate that two keys have been pressed. Therefore, simultaneous pressing of all key buttons 25 in the row associated with the first optical transmission members 13a-13c can be detected by this logic circuit.

Similarly, the key button 25c is the key button 25a.
If pressed at the same time, no light from the light source 81 will be detected by the sensor 39 when the light source 81 is activated. Thereafter, when light source 83 is activated, no light is detected by sensor 39. Therefore, the logic provides an indication that both keys 25c and 25a were pressed at the same time. If keys 25a, 25b and 25c are pressed simultaneously, only sensor 39 will be unable to detect the light from light source 81 during its activation time, and then both sensors 39 and 85 will be unable to detect light from light source 83 during its activation time. Unable to detect light. Therefore, the system logic can determine that all three key buttons have been pressed.

Referring to FIG. 8, a schematic diagram of the detection logic circuit 101 of the keyboard of the present invention is shown. This circuit 101 includes a microprocessor 103 and a decoder/driver circuit 105. This microprocessor is programmed to provide a clocked output signal on bus 107 to decoder/driver circuit 105. Meanwhile, decoder/driver circuit 105 provides an output signal on line 109 to a plurality of corresponding light emitting diodes (LEDs) 111. These light emitting diodes correspond to light sources 37, 81, 83 on light source assembly 19 of FIG. The signals provided on line 109 are mutually exclusive and ordered in time. Additionally, microprocessor 103 is responsive to a sensor 113 connected to its input port by line 115. Sensor 113 corresponds to sensors 39, 85-88 in FIG.

Referring to FIG. 9, a logic flow diagram of the keyboard assembly of the present invention is shown. Microprocessor 103 of FIG. 8 initializes its registers and arrays upon power-on, as indicated by block 121. Thereafter, a register count is set equal to one, as indicated by block 123, and a first light emitting diode (LED), such as light source 81 of FIG. 1, is turned on, as indicated by block 125. . After a delay as indicated by block 127, as indicated by block 129,
The outputs of sensors 39, 85-88 are extracted and a test is performed as indicated by block 131 to determine whether the indications provided by these sensors have changed. Key button 25 (Figure 1)
If there is no change indicating that the light sources 81-83-37 are not activated, a test is performed to determine whether all light sources 81-83-37 have sequentially activated, as indicated by block 133, and if they have not. If so, the count is incremented as indicated by block 135 and block 12
The next light emitting diode to be energized is turned on as indicated by 5. If all light sources have been energized, the count is set equal to light source 1, as indicated by block 123, and the procedure is repeated again.

Whenever the state of a key changes from the previous interrogation state, block 131 indicates change information, which information is stored in a temporary file and a flag is set to indicate that a change has been detected. Change information specifying a particular key press is stored for subsequent processing by microprocessor 103 of FIG. This microprocessor instructs the utilization device whether a particular key button 25 has been actuated or not. This is generally indicated by block 137.

Although the above description discloses the keyboard of the invention with a matrix of rows and columns that intersect at right angles to each other, various keyboard configurations with non-parallel rows and columns can be used without departing from the spirit of the invention. It will be clear to those skilled in the art that Furthermore, although independent parts forming the first light transmission member are disclosed and formed in combination with the support plate 23, the single part formed in combination with the support plate 23 is It is also clear that the present invention can be used for one optical transmission member. An advantage of the present invention is that a relatively small number of individual components are required to provide an optical keyboard with N key rollover capability.

Although the invention has been particularly shown and described with reference to this preferred embodiment, those skilled in the art will appreciate that these and other changes in form and detail may be made without departing from the spirit and scope of the invention. This is what I understand.

[Brief explanation of drawings]

FIG. 1 is a partial perspective view of a keyboard assembly constructed according to the present invention, FIG. 2 is a side sectional view of a portion of the keyboard assembly, and FIG. 3 is a plan view of a first light transmission member. FIG. 4 is a side view of the first optical transmission member, FIG. 5 is an end view of the first optical transmission member, and FIG. 6 is a side view of a part of the second optical transmission member.
FIG. 7 is a partial end view of the second optical transmission member;
9 is a schematic diagram of the detection logic circuit of the keyboard of the present invention, and FIG. 9 is a flowchart of the logic of the keyboard of the present invention. 25a, 25b, 25cc...key, 81, 8
3, 37... light source, 13a, 13b, 13c...
First optical transmission member, 15... second optical transmission member,
29...Shutoff device, 39, 85, 86, 87, 8
8...Sensor.

Claims (1)

[Claims] 1. A plurality of keys arranged in a matrix of M rows by N rows, at least N light sources provided for each column and generating N light beams; a first optical transmission member having a terminal point for each row, each having at least N common optical transmission paths for transmitting from one of the N light sources to the M terminal points; at least M common optical transmission paths each having N optical receivers, each of the N optical receivers of the M optical transmission paths forming an optical path therebetween; a second optical transmission member aligned with terminal points of different optical transmission paths of the first optical transmission member; and a second optical transmission member, each responsive to the pressing of a different key, to block the optical path between them when the key is pressed. a plurality of circuit breakers uniquely located between the terminal points and the corresponding optical receivers; each circuit breaker for detecting the presence or absence of light transmitted along its associated second optical transmission path; M light sensors arranged in different ones, and a logic device for sequentially operating said light sources in time and extracting the output signals of said sensors to provide a logic instruction indicating which key is pressed. The first optical transmission member has M reflective surfaces along the transmission path of each of the N light beams, and each reflective surface reflects a portion of its associated light beam. 1st
vertically reflected from its first traveling surface in a transmission member to a second traveling surface in said first transmission member, with a portion of said light beam vertically displaced from said first traveling surface. M for reflecting along the third traveling surface in the first transmission member in a direction substantially perpendicular to the traveling direction of the light beam on the first traveling surface.
each of the M common optical transmission paths for directing light from the light receiver to the optical sensor along each of the M common optical transmission paths; An optical keyboard comprising at least N reflective surfaces.