Patent Application
20090051558
Transceiver connector modules typically provide for bi-directional data transmission between two or more devices, such as modems, network interfaces and computer systems. Small Form-Factor Pluggable (SFP) transceiver modules are one industry standard used for this purpose. SFP supports both fiber optic and cable assemblies. The SFP transceiver module is inserted into a complimentary metal cage assembly mounted to a printed circuit board. In order to verify that a connection has been established between the transceiver modules, indicators, such as light emitting diodes (LEDs), are incorporated into the printed circuit board behind the SFP cage to indicate whether or not data is being received. Because the circuit connection is established behind a front panel of a circuit board that supports these devices, the status of the circuit, and the light generated by an associated LED, must be relayed outside of the device to an operator's side of the front panel for an operator to know the status of a circuit.
An ability to provide visual monitoring of the status of internal circuits is useful to knowing the functional state of transceiver modules or other circuits on a circuit board. One approach to this problem is to incorporate an optical waveguide or “light pipe” adjacent to the LED mounted on the printed circuit board such that it extends to the front panel. The optical waveguide transmits the LED-emitted light to a display area on the front panel. However, advances in the telecommunications industry and the quest for greater functionality have diminished the circuit board space available for devices providing state information of a circuit to an observer at a rack supporting the circuit board.
One example embodiment of the invention is an apparatus or corresponding method to indicate the state of a circuit. The example embodiment of the invention may include a connector component connected to a circuit board to accept a mating connector component at a location that may be a non-perpendicular first angle relative to an edge of the circuit board. The example embodiment may also include an optical light transmission element and at least three mounting features to connect the transmission element to the circuit board. The optical light transmission element may include a light-receiving end configured to accept a light projected by an optical light-generating device configured to illuminate as a function of a state of the circuit. The optical light transmission element may further include a light propagation region configured to support propagation of the light for a given length. The optical light transmission element may also include a light-emitting end to output the light at the mating location of the connector component at a second angle relative to the edge of the circuit board, other than at the first angle, to associate light output by the light-emitting end with the state of the circuit on the circuit board.
The foregoing will be apparent from the following more particular description of example embodiments of the invention, as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating embodiments of the present invention.
A description of example embodiments of the invention follows.
Telecommunications industry advances have reduced circuit board space availability for devices providing state information of a circuit to an observer at a rack supporting a circuit board with the circuit. There is also a trend in the telecommunication industry, and other industries, towards development of high density transceiver components, which, in some applications, causes small form-factor pluggable (SFP) cage modules to be angled to increase their density. In such cases, the spatial allotment and placement positions available for state information indicators, including light guides that project light representing a state of a circuit, are even more restricted.
Because of this, many light guides are either mounted in an unstable manner, making them prone to tilting, especially where multiple light guides are to be positioned relative to each other during assembly and aligned at a perpendicular angle for assembly with a front panel. The cost of manufacturing electronic equipment containing conventional light guides is increased by this problem, as is the difficulty in dismantling front display panels and circuit boards for servicing.
A conventional light guide typically provides stability by fastening the light guide to a connector module with a clip. Other conventional methods utilize notched hooks on a light-emitting end of the light guide for hooking the light guide to an inside of the front panel. However, neither of these solutions provides satisfactorily secure mounting, and neither allows the connector module to be angled through the front panel at an angle other than a 90 degree angle (i.e., perpendicular). A 90 degree angle decreases a density of connector modules that can be mounted on a given circuit board, increases manufacturing and repair costs of the devices, and decreases overall functionality.
An example embodiment of the present invention is an apparatus and corresponding method for providing optical indications about a state of a circuit on a circuit board. A connector component is positioned at a non-perpendicular first angle relative to an edge of the circuit board and configured to accept a mating component. The example apparatus includes an optical light transmission element with at least three mounting features. The mounting features allow the transmission element to be secured to the circuit board at a straight or angled position relative to the connector component. The transmission element further includes a light-receiving end that accepts light projected by an optical light-generating device, such as a light-emitting diode (LED). The light-generating device itself is configured to illuminate as a function of a state of a circuit. The light transmission element also includes a light propagation region configured to support propagation of the light for a given length. The transmission element also has a light-emitting end to output the light at a location near where the connector component accepts the mating component. The light is outputted at a second angle relative to the edge of the circuit board, the second angle being different from the first angle of the connector component relative to the edge of the circuit board. The light-emitting end thereby associates the light output by the transmission element with the state of the circuit on the circuit board associated with the connector component.
The mounting features may be configured to be press-fitted into the circuit board, which allows the light-receiving end to be positioned above a surface-mounted LED, for example. The LED may be a multi-colored LED.
The light propagation region may include at least one geometric structure supporting propagation of the light. Further, there may be multiple geometric structures configured to be parallel to each other with at least one support connecting the parallel geometric structures to provide structural stiffness of the geometric structure. The geometric structure(s) may cause the light to be redirected along a path substantially offset from, and along, a longitudinal axis of a surface plane of the circuit board. The light propagation region may be constructed of clear plastic.
The connector component may include a standard Small Form-Factor Pluggable (SFP) cage. The SFP cage may be mounted to the circuit board. In order to increase the density connector components on the circuit board, the SFP cage may be arranged in angled rows with transceiver module cages plugged into the receptacle SFP cages.
The light-emitting end may include a textured surface through which the light is outputted to ensure visibility from a broad range of viewing angles. The light-emitting end may be configured to output light through a front panel housing the circuit board. The outputted light may provide optical indications of the state of the circuit connected to the SFP cage as a function of light generated by the LED.
The light transmission element may be attached to the circuit board without modification. An example embodiment of the invention includes a single-piece structure that eliminates need for a separate clip, increases stability, reduces costs, and permits increased transceiver module connector density compared to conventional light guides.
The optical light transmission elements 215 may include at least three mounting features to secure it soundly to a circuit board for ease of assembly with a front panel. Assembly through a front panel is facilitated by maintaining the ends of multiple light transmission elements 215 in alignment relative to each other. Enhanced stability allows multiple light guides to be packaged in closer proximity and presented at an angle. The example embodiment reduces the cost of assembling electronic equipment and further permits a reduction in size of the equipment. The optical light transmission elements 215 are mechanically independent from connector components 312.
The parallel light propagation regions 418 may be a geometric structure and may be rectangular in shape or have another shape that can support propagation of light. Further, there may be a support 422 between the adjacent parallel geometric structures 419. This example embodiment also includes a light-emitting end 425 with a textured surface 430.
While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims.
For example, any material or combination of materials of sufficient optical clarity that can support total internal reflection and the propagation of light may be used to compose optical light transmission elements by way of example herein. Although the geometric structure of the light propagating regions are generally illustrated as being square or rectangular, it should be understood that almost any shape may employed. In addition, the mounting features may be press-fit pins or other functionally equivalent components. For example, although the mounting may be press-fitted into holes in the circuit board, an adhesive material may also be used. Similarly, although three mounting features are illustrated in the embodiments above, additional mounting features may be utilized. The mounting features may be ribbed and cylindrical, but additional smooth shapes may also be utilized. Further, the inclination of the internal reflection surface and the shape of the curved portion may vary. The length of propagation may be shortened or lengthened. Injection molding may be used to produce the various embodiments above, but other manufacturing processes may be utilized.
