Secondary optics with air circulation for light emitting devices

Abstract

A secondary optics device (200) includes a body (210); an LED cavity (220) located in the body at a position corresponding to an LED for refraction of light through the body; a ventilation channel (230) in the body fluidically coupled to the LED cavity (140); and an egress opening (240) in the body fluidically coupled to the ventilation channel.

Description

ETN-095XINPCTP23-1757WO01SECONDARY OPTICS WITH AIR CIRCULATION FOR LIGHT EMITTING DEVICESBACKGROUND

[0001] Conventionally, a light emitting diode (LED) of a lighting fixture is fitted within a cavity with reflective walls such that light emitted from the LED can be directed to illuminate an intended area. For the conventional structure, the reflective walls of the cavity may be considered secondary optics, along with any additional optics that may be included for additional modifications to the light output, for example, to adjust intensity distribution, angle, and the like. Secondary optics are disposed above the LED to direct light emitted from the LEDs to illuminate an intended area. Air volume can get trapped inside the cavity, which can degrade thermal performance of the LEDs and can cause a change in color of the secondary optics due to increased temperature from heat generation. Additionally, materials used in the construction of lighting fixtures often emit volatile organic compound (VOCs). These VOCs get accumulated inside the cavity of secondary optics overtime. This chemical exposure further degrades the performance of the LED and reliability of the lighting fixture.BRIEF SUMMARY

[0002] Secondary optics with air circulation for light emitting devices are provided. Through the secondary optics configurations described herein, it is possible to circulate hot air through cavities of secondary optics in a lighting fixture. The circulation of air as described can, in various embodiments, dilute VOC concentration, improve cooling efficiency, and enhance reliability of LED performance.

[0003] A secondary optics device includes a body; an LED cavity located in the body at a position corresponding to an LED for refraction of light through the body; a ventilation channel in the body fluidically coupled to the LED cavity; and an egress opening in the body fluidically coupled to the ventilation channel.

[0004] This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used to limit the scope of the claimed subject matter.BRIEF DESCRIPTION OF THE DRAWINGS

[0005] FIG. 1 shows a cross-section of a portion of a lighting fixture incorporating a secondary optics with air circulation.ETN-095XINPCTP23-1757WO01

[0006] FIGs. 2A and 2B illustrate example cross-sections of a portion of a secondary optics device.

[0007] FIGs. 3A and 3B provide details of parts of a secondary optics device.

[0008] FIG. 4 shows a top perspective view of an example implementation of a secondary optics device with air circulation.

[0009] FIGs. 5A and 5B show example top views of a secondary optics device.

[0010] FIGs. 6A-6D show various example ventilation channel configurations for secondary optics devices.

[0011] FIGs. 7A and 7B show a top and bottom view of an example secondary optics device with multiple concentric rows of cavities.DETAILED DESCRIPTION

[0012] Secondary optics with air circulation for light emitting devices are provided. Through the secondary optics configurations described herein, it is possible to circulate air inside a lighting fixture. As described herein, it is possible to circulate hot air through cavities of secondary optics in a lighting fixture. The circulation of air as described can, in various embodiments, dilute VOC concentration, improve cooling efficiency, and enhance reliability of LED performance.

[0013] FIG. 1 shows a cross-section of a portion of a lighting fixture incorporating a secondary optics with air circulation. Referring to FIG. 1, lighting fixture 100 includes an LED board 110 and a secondary optics device 120 within a housing 130. A lighting fixture is a lighting device having one or more light sources and corresponding electronics within a housing so as to provide illumination to an environment. Lighting fixtures can be free-standing (e.g., portable) or fixed.

[0014] In some cases, such as shown in the example of FIG. 1, the housing 130 can enclose the lighting and electrical components of the lighting fixture. For example, a molded window 135 may be used to enclose the LED board 110, secondary optics device 120, and other circuitry.

[0015] Secondary optics device 120 is used to direct light emitted from LEDs on the LED board 110. For example, an LED cavity 140 of secondary optics device 120 is located at a position corresponding to an LED 150 that is coupled to the LED board 110. Light emitted from LED 150 transmits and refracts through the secondary optics device 120. A ventilation channel 160 fluidically coupled to the LED cavity 140 enables air circulation at least between the cavity 140 and a space within housing 130.ETN-095XINPCTP23-1757WO01

[0016] Ventilation channel 160 in the secondary optics device 120 can connect the small cavities above the LEDs (e.g., LED cavity 140 above LED 150) to a larger compartment or external area, which enables dissipation of heat from the LED cavities due to the thermal gradient between the cavities and the larger compartment / extemal area and the diffusion of any VOCs from the LED cavities due to the concentration gradient between the cavities and the larger compartment / extemal area.

[0017] Advantageously, damage and decreased performance caused by accumulation of heat caused by operation of the LEDs and any VOCs released by materials like adhesive and thermal interfacing materials in the fixture can be ameliorated by various embodiments of a secondary optics with air circulation design as described herein.

[0018] FIGs. 2A and 2B illustrate example cross-sections of a portion of a secondary optics device. Referring to FIG. 2A, secondary optics device 200 includes a body 210, an LED cavity 220 located in the body 210 for refraction of light through the body 210; a ventilation channel 230 in the body 210 fluidically coupled to the LED cavity 220; and an egress opening 240 in the body 210 fluidically coupled to the ventilation channel 230.

[0019] As illustrated in FIG. 2A, egress opening 240 can be located at a side surface of the body 210. The side surface of the body containing the egress opening 240 may be an exterior side surface or an interior side surface. Examples of implementations of a secondary optics device with egress opening at a side surface of the body are shown in FIGs. 4, 6A, 6B, and 6D

[0020] FIG. 2B similarly shows a secondary optics device 250 that includes a body 260, an LED cavity 270 located in the body 260 for refraction of light through the body 260; a ventilation channel 280 in the body 260 fluidically coupled to the LED cavity 270; and an egress opening 290 in the body 260 fluidically coupled to the ventilation channel 280. Here, egress opening 290 for ventilation channel 280 is located in a top surface of the body 260. An example of an implementation of a secondary optics device with egress opening in a top surface of the body is shown in FIG. 6C. Although not shown in the illustrated examples, a secondary optics device can utilize egress openings at one or both side surface as well as the top surface of the body. In addition, more than one egress opening can be provided for a particular ventilation channel (e.g., two or more egress openings may be provided for ventilation channel 280).

[0021] FIGs. 3A and 3B provide details of parts of a secondary optics device. As explained above, ventilation channels enable dissipation of heat from LED cavities and can also function to clear VOCs. In addition to dissipation performance, since secondary optics devices can beETN-095XINPCTP23-1757WO01 coupled to an LED board over the LEDs and serve to direct light from the LEDs in a desired direction and / or pattern, the positioning and sizing of the ventilation channels within the body of the secondary optics devices can be optimized, for example, to have minimal impact on light emitting efficiency.

[0022] An LED is formed of multiple layers and typically has an n-type layer, an active layer, and a p-type layer. LEDs emit light / photons from the active layer at the p-n junction when electric current flows through the device. This p-n junction forms a light emitting surface within the LED. The thickness of an LED may vary depending on fabrication process, materials, and package configuration. However, for optimal light emitting efficiency, the depth of the ventilation channel is made to be less than the distance between a bottom of the LED substrate (where the LED is attached to an LED board or package) and the light emitting surface within the LED.

[0023] For example, referring to FIGs. 3A and 3B, a depth d of ventilation channel 300 in a body 310 of a secondary optics device is less than a height h of a light-emitting surface 320 of an LED 330 positioned below an LED cavity 340. The height h of the light-emitting surface 320 is the distance between a bottom of the LED substrate 350 of the LED (or the surface 360 of the LED board to which the LED attaches) and the light-emitting surface 320.

[0024] With reference to FIG. 3B, the width w of the ventilation channel 300 can be based on manufacturing constraints, for example, impacts on molding the portion 315 of the body containing the cavity 340.

[0025] FIG. 4 shows a top perspective view of an example implementation of a secondary optics device with air circulation. Referring to FIG. 4, secondary optics device 400 includes a body 410 having an annular shape with an interior side surface 412 and an exterior side surface 414. The top surface 416 of the body 410 includes the protruding portions 418 corresponding to the cavities. In the example implementation shown in FIG. 4, egress openings are provided to both the interior side surface 412 and the exterior side surface 414. For example, egress opening 420 is located at the exterior side surface 414 and egress opening 430 is located at the interior side surface 412.

[0026] FIGs. 5A and 5B show example top views of a secondary optics device. Referring to FIGs. 5A and 5B, it can be seen that a variety of cavity shapes are possible, including variation in major and minor axis radii.

[0027] FIGs. 6A-6D show various example ventilation channel configurations for secondary optics devices. FIG. 6A shows an example ventilation channel configuration providing egress openings to both an exterior side surface 602 and an interior side surface 604ETN-095XINPCTP23-1757WO01 of a secondary optics device 600. Here, each cavity that is located near the exterior side surface 602 has a ventilation channel extending from the cavity to a corresponding egress opening at the exterior side surface 602 (e.g., cavity 610 has a ventilation channel 612 extending to egress opening 614 at the exterior side surface 602) and each cavity located near the interior side surface 604 has a ventilation channel extending from the cavity to a corresponding egress opening at the interior side surface 604 (e.g., cavity 620 has a ventilation channel 622 extending to egress opening 624 at the interior side surface 604). Air circulation can be provided all the way through the body from the exterior side surface 602 to the interior side surface 604 (and vice versa) by further including ventilation channels between cavities near the exterior side surface and cavities near the interior side surface (e.g., ventilation channel 626 between cavity 610 and cavity 620). When there are more cavities near the exterior side surface than cavities near the interior side surface, then it is also possible for cavities near the interior side surface to have a ventilation channel to multiple cavities near the exterior side surface, forming outward branches. The branching configuration can also be used in designs with more than two rows / concentric circles to connect cavities with ventilation channels not directly coupled to an egress at one of the side surfaces. For example, where there are inner LED cavities, middle LED cavities (e.g., at a radius between the inner LED cavities and the outer LED cavities), and outer LED cavities, the inner LED cavities can be coupled to two ventilation channels that are each fluidically coupled to a corresponding middle LED cavity, which is fluidically coupled to one or more ventilation channels that are themselves fluidically coupled to outer LED cavities. As shown in FIG. 6A, the illustrated configuration for secondary optics device 600 enables air circulation from the open interior space of the annular shaped body to around the exterior side surface (and vice versa).

[0028] In this manner, a secondary optics device can include a plurality of LED cavities including inner LED cavities located closer to an interior side surface of the body and outer LED cavities located closer to an exterior side surface of the body; wherein the inner LED cavities are each fluidically coupled to a ventilation channel that is fluidically coupled to a corresponding egress opening located at the interior side surface of the body; wherein the inner LED cavities are each fluidically coupled to two ventilation channels that are each fluidically coupled to a different outer LED cavity; and wherein the outer LED cavities are each fluidically coupled to a ventilation channel that is fluidically coupled to a corresponding egress opening located at the exterior side surface of the body.

[0029] FIG. 6B shows an example ventilation channel configuration providing egress openings to only an exterior side surface 632 of a secondary optics device 630. Here, eachETN-095XINPCTP23-1757WO01 cavity that is located near the exterior side surface 632 has a ventilation channel extending from the cavity to a corresponding egress opening at the exterior side surface 632 (e.g., cavity 640 has a ventilation channel 642 extending to egress opening 644 at the exterior side surface 632 and cavity 645 has a ventilation channel 646 extending to egress opening 648 at the exterior side surface 632). Each cavity located near the interior side surface 634 has a ventilation channel extending to at least one of the cavities near the exterior side surface 632 (e.g., cavity 650 has a first ventilation channel 652 connecting cavity 650 to cavity 640 and a second ventilation channel 654 connecting cavity 650 to cavity 645, providing a “V” shaped air circulation path). Additional cavities can be included in the “V” shaped air circulation paths, for example, in designs with more than two rows / concentric circles. For example, path 728 of FIG. 7B includes a V-shaped circulation path with more than three cavities.

[0030] FIG. 6C shows an example ventilation channel configuration with egress openings to a top surface of a secondary optics device 660. Here, cavities are arranged in concentric circles with ventilation channels connecting adjacent cavities in a circle. Egress openings can be disposed on one or more ventilation channels of a connected circle. For example, an egress opening can be disposed at each ventilation channel, every other ventilation channel, or some other pattern in the circle. In the illustrated example, an outer concentric circle 670 is formed of a plurality of cavities with ventilation channels arranged between adjacent cavities (e.g., ventilation channel 672 between cavity 674 and 676) and an inner concentric circle 680 is formed of a plurality of cavities with ventilation channels arranged between adjacent cavities (e.g., ventilation channel 682 between cavity 684 and 686). An egress opening at every other ventilation channel is shown (e.g., egress opening 688 is disposed at ventilation channel 672 but not ventilation channel 678 coupled to the other side of cavity 674).

[0031] In this manner, a secondary optics device can include a plurality of LED cavities arranged in the body in concentric circles; and a plurality of ventilation channels arranged between adjacent LED cavities for each concentric circle. Egress openings to a surface (e.g., top and / or bottom surface) of the body can be provided at select ventilation channels.

[0032] In some cases, not all cavities are arranged with ventilation channels forming a circular air circulation path. For example, in one implementation, a first plurality of ventilation channels can be arranged between adjacent inner LED cavities forming an inner concentric ventilation circle, a second plurality of ventilation channels can be arranged between inner LED cavities and outer LED cavities, and a third plurality of ventilation channels can be arranged providing fluidic coupling to egress openings at the exterior side surface of the body; wherein each inner LED cavity is fluidically coupled to a ventilation channel of the second plurality ofETN-095XINPCTP23-1757WO01 ventilation channels that is fluidically coupled to an outer LED cavity of the outer LED cavities; wherein the outer LED cavities are each fluidically coupled to a ventilation channel of the third plurality of ventilation channels that is fluidically coupled to a corresponding egress opening located at the exterior side surface of the body.

[0033] As another example, in another implementation, a first plurality of ventilation channels can be arranged between adjacent outer LED cavities forming an outer concentric ventilation circle, a second plurality of ventilation channels can be arranged between inner LED cavities and outer LED cavities, and a third plurality of ventilation channels can be arranged providing fluidic coupling to egress openings at the interior side surface of the body; wherein each inner LED cavity is fluidically coupled to a ventilation channel of the second plurality of ventilation channels that is fluidically coupled to an outer LED cavity of the outer LED cavities; wherein the inner LED cavities are each fluidically coupled to a ventilation channel of the third plurality of ventilation channels that is fluidically coupled to a corresponding egress opening located at the interior side surface of the body

[0034] FIG. 6D shows an example ventilation channel configuration for a secondary optics device 690 with ventilation channels coupling cavities to each adjacent cavity. Here, cavities are connected by ventilation channels in concentric circles (e.g., outer concentric circle 692 and inner concentric circle 694) and have a ventilation channel configuration providing egress openings to both an exterior side surface 696 and an interior side surface 698. In this manner, a secondary optics device can include a plurality of LED cavities arranged in the body in concentric circles; and a plurality of ventilation channels which include ventilation channels arranged between adjacent LED cavities for each concentric circle, ventilation channels fluidically coupled between LED cavities located closer to an interior side surface of the body and corresponding egress openings located at the interior side surface of the body, ventilation channels fluidically coupled between the LED cavities located closer to the interior side surface of the body and LED cavities located closer to an exterior side surface of the body, and ventilation channels fluidically coupled between the LED cavities located closer to the exterior side surface of the body and corresponding egress openings located at the exterior side surface of the body.

[0035] FIGs. 7A and 7B show a top and bottom view of an example secondary optics device with multiple concentric rows of cavities. Referring to FIGs. 7A and 7B, secondary optics device 700 can have multiple concentric rows of cavities. In the example implementation, cavities of the various concentric rows are not all spaced equidistant from each other and various arrangements of cavities are possible. The internal cavity shape can also beETN-095XINPCTP23-1757WO01 different than the portion of the body containing the cavity. For example, different radii and shapes may be used (see e.g., portion of the body 702 and corresponding cavity 704, which have different curvature and orientation for oval -like shapes).

[0036] In addition, various configurations for ventilation channels and egress openings are possible - even for the same secondary optics device. Referring to FIG. 7B, egress openings can be located at an exterior side surface 710 (e.g., egress opening 712), an interior side surface 714 (e.g., egress opening 716), and atop surface 718 (e.g., egress opening 720) ofthe secondary optics device 700. Ventilation channels can be disposed connecting cavities to one or more of the various types of egress openings. As one example, a ventilation path 722 can connect multiple cavities with egress between the interior side surface 714 and the exterior side surface 710. One or more egress openings to the top surface 718 can be included in the ventilation path 722. A similar ventilation pathway in a radial direction can utilize an egress opening at a top surface as one end of the ventilation pathway and an egress opening at either the exterior side surface 710 or the interior side surface 714 for the other end. For example, ventilation path 724 can have a ventilation channel fluidically coupled to an egress opening 726 to the top surface 718 at one end and an egress opening at the exterior side surface 710 for the other end.

[0037] As another example, a V-shaped circulation path 728 can connect multiple cavities with egress to the exterior side surface 710. Here, V-shaped circulation path 728 also includes egress openings to the top surface 718, including at the join for the V-shaped circulation path (e.g., with egress opening 730). Branching connections can also be included, utilizing the egress opening 730 to provide air circulation support with fewer cavities to traverse before reaching an egress opening.

[0038] Although the subject matter has been described in language specific to structural features and / or acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as examples of implementing the claims and other equivalent features and acts are intended to be within the scope of the claims.

Claims

ETN-095XINPCT P23-1757WO01CLAIMSWhat is claimed is:

1. A secondary optics device, comprising: a body; an LED cavity located in the body for refraction of light through the body; a ventilation channel in the body fluidically coupled to the LED cavity; and an egress opening in the body fluidically coupled to the ventilation channel.

2. The secondary optics device of claim 1, wherein a depth of the ventilation channel in the body is less than a height of a light-emitting surface of an LED positioned below the LED cavity.

3. The secondary optics device of claim 1, wherein the egress opening is located on a top surface of the body.

4. The secondary optics device of claim 1, wherein the egress opening is located at an exterior side surface of the body.

5. The secondary optics device of claim 1, wherein the egress opening is located at an interior side surface of the body.

6. The secondary optics device of claim 1, further comprising: a plurality of LED cavities located in the body at positions corresponding to a plurality of LEDs for refraction of light through the body; and a plurality of ventilation channels in the body fluidically coupled to the plurality of LED cavities.

7. The secondary optics device of claim 6, wherein each ventilation channel of the plurality of ventilation channels is fluidically coupled to one or more of the plurality of LED cavities.

8. The secondary optics device of claim 6, wherein:ETN-095XINPCTP23-1757WO01 the plurality of LED cavities is arranged in the body in concentric circles; and the plurality of ventilation channels is arranged between adjacent LED cavities for each concentric circle.

9. The secondary optics device of claim 6, wherein: the plurality of LED cavities is arranged in the body in concentric circles; and the plurality of ventilation channels comprises ventilation channels arranged between adjacent LED cavities for each concentric circle, ventilation channels fluidically coupled between LED cavities located closer to an interior side surface of the body and corresponding egress openings located at the interior side surface of the body, ventilation channels fluidically coupled between the LED cavities located closer to the interior side surface of the body and LED cavities located closer to an exterior side surface of the body, and ventilation channels fluidically coupled between the LED cavities located closer to the exterior side surface of the body and corresponding egress openings located at the exterior side surface of the body.

10. The secondary optics device of claim 6, wherein the plurality of LED cavities comprises inner LED cavities located closer to an interior side surface of the body and outer LED cavities located closer to an exterior side surface of the body; wherein the inner LED cavities are each fluidically coupled to a ventilation channel that is fluidically coupled to a corresponding egress opening located at the interior side surface of the body; wherein the inner LED cavities are each fluidically coupled to two ventilation channels that are each fluidically coupled to a different outer LED cavity; and wherein the outer LED cavities are each fluidically coupled to a ventilation channel that is fluidically coupled to a corresponding egress opening located at the exterior side surface of the body.

11. The secondary optics device of claim 6, wherein the plurality of LED cavities comprises inner LED cavities located closer to an interior side surface of the body and outer LED cavities located closer to an exterior side surface of the body; wherein the inner LED cavities are each fluidically coupled to two ventilation channels that are each fluidically coupled to a different outer LED cavity; andETN-095XINPCTP23-1757WO01 wherein the outer LED cavities are each fluidically coupled to a ventilation channel that is fluidically coupled to a corresponding egress opening located at the exterior side surface of the body.

12. The secondary optics device of claim 6, wherein the plurality of LED cavities comprises inner LED cavities located closer to an interior side surface of the body, outer LED cavities located closer to an exterior side surface of the body, and middle LED cavities located at a radius between the inner LED cavities and the outer LED cavities; wherein the inner LED cavities are each fluidically coupled to two ventilation channels that are each fluidically coupled to a corresponding middle LED cavity; wherein middle LED cavities are each fluidically coupled to one or more ventilation channels fluidically coupled to a corresponding outer LED cavity.

13. The secondary optics device of claim 6, wherein the plurality of LED cavities comprises inner LED cavities located closer to an interior side surface of the body and outer LED cavities located closer to an exterior side surface of the body; wherein the plurality of ventilation channels comprises a first plurality of ventilation channels arranged between adjacent inner LED cavities forming an inner concentric ventilation circle, a second plurality of ventilation channels between inner LED cavities and outer LED cavities, and a third plurality of ventilation channels providing fluidic coupling to egress openings at the exterior side surface of the body; wherein each inner LED cavity is fluidically coupled to a ventilation channel of the second plurality of ventilation channels that is fluidically coupled to an outer LED cavity of the outer LED cavities; wherein the outer LED cavities are each fluidically coupled to a ventilation channel of the third plurality of ventilation channels that is fluidically coupled to a corresponding egress opening located at the exterior side surface of the body.

14. The secondary optics device of claim 6, wherein the plurality of LED cavities comprises inner LED cavities located closer to an interior side surface of the body and outer LED cavities located closer to an exterior side surface of the body; wherein the plurality of ventilation channels comprises a first plurality of ventilation channels arranged between adjacent outer LED cavities forming an outer concentric ventilation circle, a second plurality of ventilation channels between inner LED cavities and outer LEDETN-095XINPCTP23-1757WO01 cavities, and a third plurality of ventilation channels providing fluidic coupling to egress openings at the interior side surface of the body; wherein each inner LED cavity is fluidically coupled to a ventilation channel of the second plurality of ventilation channels that is fluidically coupled to an outer LED cavity of the outer LED cavities; wherein the inner LED cavities are each fluidically coupled to a ventilation channel of the third plurality of ventilation channels that is fluidically coupled to a corresponding egress opening located at the interior side surface of the body.

15. A lighting fixture, comprising: a light emitting diode (LED) board; an LED coupled to the LED board; and a secondary optics device coupled to the LED board over the LED, the secondary optics device configured according to any of claims 1-14.

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