WO2022020630A2

WO2022020630A2 - Wide field of view infrared transceiver optics

Info

Publication number: WO2022020630A2
Application number: PCT/US2021/042828
Authority: WO
Inventors: Eric Haseltine
Original assignee: Discovery Democracy LLC
Priority date: 2020-07-22
Filing date: 2021-07-22
Publication date: 2022-01-27
Also published as: WO2022020630A3

Abstract

In some embodiments, an apparatus includes an optical prism cover plate substantially transparent to infrared (IR). The optical prism cover plate is configured to be operatively coupled to at least one of an IR receiver or an IR emitter. The optical prism cover plate is configured to re-direct IR energy to or from the at least one IR receiver or IR emitter to expand an active field of view to at least 180 degrees, during operation of the at least one IR receiver or IR emitter.

Description

WIDE FIELD OF VIEW INFRARED TRANSCEIVER OPTICS

Cross-Reference to Related Applications

[1] This application claims priority to U.S. Provisional Patent Application No. 63/054,883, filed on July 22, 2020 and entitled “Wide Field of View Infrared Transceiver Optics,” which is incorporated herein by reference in its entity.

BACKGROUND

[2] Near infrared (JR) transmiters and receivers are used in a wide varied of optical communication systems such as remote controls, proximity sensors and motion detectors. In some applications of IR technology, such as proximity detection and motion detection, the angular field of view of IR receivers and transmitters is limited due to the constrained angle of transmission or reception of IR semiconductor active and passive components. A horizontal field of view of 120 degrees, for example, is typically the upper limit of what IR semiconductor components can achieve.

[3] Thus when greater than 120-degree field of view operation is desired, multiple IR emitters, angled away from each other are typically used, adding unwanted cost, complexity, size and weight to IR systems that are desired to have extremely wide fields of view.

[4] For example, for an IR proximity transceiver worn by one person that detects the presence of another, similar transceiver worn by another person to warn of a violation of social distancing requirements, it is desirable for the IR proximity transceiver to have a full 180-degree field of view to adequately alert that social distance limits have been breached. [5] Thus, a need exists to increase the field of view of IR emitters and receivers up to 180 degrees to provide adequate activation for applications of IR technology, such as proximity sensing and motion detection, that require very wide fields of view.

BRIEF DESCRIPTION OF THE DRAWINGS

[6] Figure 1 shows an optical ray trace for a sensor/ emitter without optics and an optical ray trace for a sensor / emitter with field-expanding optics, according to an embodiment.

[7] Figure 2 shows an optical ray trace for a sensor / emitter with field-expanding optics, according to another embodiment.

[8] Figures 3-5 show a system having a top view with the prism cover plate, a top view' without the prism cover plate and a perspective view with the prism cover plate, respectively, according to an embodiment.

DETAILED DESCRIPTION

[9] In the right half of the Figure 1, the red points (1) represent either an IR emitter or receiver, such as those manufactured from a flat semiconductor material (e.g., IR diodes). The cone of activation for IR receivers, or IR emission for IR transmitters, as shown by IR rays at different angles (2), is typically no greater than 120 degrees. However, as shown on the left of Figure 1, the addition of an IR-transparent prism cover plate (3) over the IR emitter or detector, positioned such that a prism captures IR energy and redirects it to or from the IR device, will greatly increase the active field of view of the IR emitter or receiver.

[10] When additional prisms are added, as shown in Figure 2, the field of view of reception or transmission of IR energy can be greatly increased in multiple directions, in some cases to greatly exceed 180 degrees, and even to “look backwards” due to the waveguide properties of the transparent prism cover plate.

[11] Although Figure 1 shows an embodiment with 90 degree prisms, other prism configurations are possible. Prism/cover-plate material can be any near IR transparent medium such as optical glass, acrylic, polystyrene or polycarbonate.

[12] It will be appreciated by those skilled in the art that the same principles of optical field view expansion using prism cover plates can also be applied to visible and ultra- violate (UV) wavelengths when it is desired to increase the active area of visible and UV optical devices.

[13] Figures 3-5 show a system having a top view with the prism cover plate, a top view' without the prism cover plate and a perspective view with the prism cover plate, respectively, according to an embodiment, according to an embodiment. As shown in these figures, the system includes a transparent prism cover plate (shown m Figures 3 and 5), a printed circuit board (PCB) (best shown in Figure 4) and a housing surrounding the PCB (best shown in Figures 4 and 5). In this embodiment, the transparent prism cover plate includes four prisms, two in a row' of the upper portion of the transparent prism cover plate and two in a row of the lower portion of the transparent prism cover plate. The location of these two pairs of prisms are based on the placement of the receiver and emitter on the PCB. This allows the two pairs of prisms to redirect light from the side of the system and even from the back of the system, providing a field of view greater than 180 degrees. In other words, although much of the refraction is accomplished by the prism portions above the remaining planar portions of the prism cover plate, the truncated prism portion below the upper surface of the prism cover plate contributes to collecting over wade field of view, as does the planar portion of the prism cover plate, which acts as a wa veguide for some rays entering/leaving from the side of the prism cover plate.

[14] in this embodiment, the cover plate is injection molded from "transparent" plastic such as poly (methyl methacrylate) (PMMA), polycarbonate or polystyrene. The cover plate can be formed with a red colorant to filter out at least a portion of visible light. The cover plate can be formed such that the prisms are monolithically formed with the remaining portions of cover plate. In other words, the prisms can be considered as squares truncated at the bottom to allow' the prisms (and the entire transparent prism plate) to sit flush on the printed circuit board (PCB) surface. Although it looks like there are two prisms (top and bottom) attached to a cover plate, in reality the top and bottom half of the prisms and the cover-plate are monolithically formed in a single piece.

[15] Because of the optical principle of reversibility, the same form of prisms will work for both emitters and receivers. As best shown in Figure 4, the PCB includes IR emitters 110, IR receivers 120 and a pow'er switch 130. For each active component (emitter or receiver), a pair of prisms positioned on opposite sides (left and right) to redirect light from the side, and even from the back onto (and away from) the active surface of the component. So, the way to think of the prism pairs for each component are that two, square shaped prisms deployed at a 45 degree angle (to create the diamond shape), truncated at the bottom. In other words, each of the prisms have approximately a 45 degree angle relative to the top surface of the remaining portions of the transparent prism cover plate.

[16] For the embodiment shown in Figures 3-5, each side of each “square” prism (discounting the truncation at the bottom of the prism) can be 6 mm. The tips of two prisms within the upper row can be 2 mm from the emitters 110 on the PCB and the tips of the two prisms within the lower row can he 3 mm from the receivers 120 on the PCB. Note that the two prisms within the lower row' are not symmetrical about the center line of the system because the receiver 120 is also offset from the center line of the PCB.

[17] While various embodiments have been described and illustrated herein, a variety of other means and/or structures for performing the function and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications are possible. More generally, all parameters, dimensions, materials, and configurations described herein are meant to be examples and the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the disclosure is used. It is to be understood that the foregoing embodiments are presented by way of example only and that other embodiments may be practiced otherwise than as specifically described and claimed. Embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.

[18] Also, various concepts may be embodied as one or more methods, of which an example has been provided. The acts performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts simultaneously, even though shown as sequential acts in illustrative embodiments.

[19] The indefinite articles “a” and “an,” as used herein in the specification and in the claims, unless clearly indicated to the contrary, should be understood to mean “at least one.”

[20] The phrase “and/or,” as used herein in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and/or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specifically identified by the “and/or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and/or B”, wtien used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements); etc. [211 As used herein m the specification and in the claims, “or” should be understood to have the same meaning as “and/or” as defined above. For example, when separating items m a list, “or” or “and/or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, hut also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used herein shall only be interpreted as indicating exclusive alternatives (i.e. “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.” “Consisting essentially of,” when used in the claims, shall have its ordinary meaning as used m the field of patent law.

Claims

1. An apparatus, comprising: an optical prism cover plate substantially transparent to infrared (IR), the optical prism cover plate configured to be operatively coupled to at least one of an IR recei ver or an IR emitter, the optical prism cover plate configured to re-direct IR energy to or from the at least one IR receiver or IR emitter to expand an active field of view to at least 180 degrees, during operation of the at least one IR receiver or IR emitter.

2. An apparatus, comprising: an optical prism cover plate substantially transparent to visible and ultraviolet (UV) energy, the optical prism cover plate configured to be operatively coupled to at least one of a receiver or an emitter for at least one of the visible band or UV band, the optical prism cover plate configured to re-direct energy to or from the at least one receiver or emitter to expand an active field of view to at least 180 degrees, during operation of the at least one receiver or emitter.