WO2019215750A1

WO2019215750A1 - Flexible led lighting element for vision systems

Info

Publication number: WO2019215750A1
Application number: PCT/IN2019/000002
Authority: WO
Inventors: R. Ramachandran
Original assignee: Ramachandran R
Priority date: 2018-05-08
Filing date: 2019-01-25
Publication date: 2019-11-14

Abstract

A flexible Lighting Element for Vision Systems and Digital Imaging Microscopes is disclosed. The inventor proposes a simple lighting assembly made of flexible PCB, surface mount diodes and current limiting resistors, wherein the flexible PCB is divided into several bent segments to ensure maximum focussing on the target object. The present invention can be used for increased proliferation of vision systems and digital imaging microscopes for Industrial, Scientific and Consumer uses.

Description

Flexible LED Lighting Element for Vision Systems

Technical Field

The present invention is related to the arrangement of electric circuit elements in or on lighting devices, and more particularly to LED lit optical gadgets and instruments such as Vision systems, Microscopes, etc.

Background Art

In the last decade, there has been increased proliferation of Vision systems and digital imaging Microscopes for Industrial, Scientific and Consumer uses. These systems need good lighting which is provided by very efficient LEDs. The newer LEDs are SMT type which are typically assembled on a metallic PCB. There is a need to mount them in a way that helps focus individual lighting assemblies at the Field of View of the optical systems.

US 5920643 discloses a flexible lighting element circuit in which the flexible circuit board is folded into a conical or doomed configuration, with the light sources facing inward, and each abutted end and lateral surfaces of the folded circuit board is suitably secured or fastened to one another to permanently retain the flexible circuit board in its folded state.

Objects of the Invention:

The object of the present invention is to develop

1. A simple SMD LED Lighting assembly where every individual LED can be focussed to maximise the light on the object which is being observed by the camera/optical system

2. The LED lighting system should be cost effective and easy to manufacture and troubleshoot.

3. There must be enough heat sinking so as to maintain reliability of the LEDs over the long life cycle. Summary of the Invention:

• In the present invention, a flexible SMD Lighting Element that can be used in LED lit optical gadgets like Vision Systems, Microscopes, etc. is disclosed.

• The said flexible SMD lighting element consists of one or more flexible PCBs and surface mount diodes mounted on the flexible PCBs with current limiting resistors.

• The flexible PCB is demarcated into multiple zones and each LED is mounted on bendable segments.

• After mounting the SM Ds on the PCB, the segments are bent at various required angles in a way as to produce different incident light angles while focussing light on the object of interest below the optics/camera.

Drawings

1. Fig 1A - Flexible Lighting Element with single ring and uniform radius - Front view

Fig IB - Flexible Lighting Element with single ring and uniform radius - Isometric view

2. Fig 2A - Flexible Lighting Element with single ring and multiple radius - Front view

Fig 2B - Flexible Lighting Element with single ring and multiple radius - Isometric view

3. Fig 3A- Flexible Lighting Element with multiple rings and multiple radius -Front view

Fig 3B - Flexible Lighting Element with multiple rings and multiple radius - Isometric view

4. Fig 4A - Flexible Lighting Element for a square shaped PCB - Front View

Fig 4B - Flexible Lighting Element for a square shaped PCB - Isometric View

5. Fig 5 - Section View showing focus of light on the target object while using Flexible Lighting Element 6. Fig 6 - Flexible Lighting Element with angular backing supports for individual .segments

7. Fig 7 - Flexible Lighting Element with circular peripheral backing supports for flexible PCB

Detailed Description

• In the present invention, the flexible PCBs are made into multiple zones, for ex: one zone in each quadrant. Each zone is further divided into segments according to the requirement.

• The SMD LEDs and the resistors are mounted at a specific radius in the PCB. Since the PCB is flexible, the segments can be bent at various required angles to provide focus on the target object as shown in Fig 1 and Fig 2.

• In the present invention, it is proposed that the segments may be bent at their base at a certain angle. The angle can be adjusted so as to focus light on the object being imaged by the optical system/camera as shown in Fig 5.

• In other embodiment of the present invention, flexible SMD lighting element with multiple flexible PCBs of different radial distances is disclosed. Specific number of segments are made in each zone of each PCB, on which the SMD and resistors are mounted at various radial distances and the multiple PCBs can be concentric as shown in Fig 3. Then the zones are bent at various required radius to provide focus on the target object. Circular PCBs is given as examples in the drawing. This invention can be applied in PCBs of any shapes, including' but not limited to, circular, elliptical, square, rectangular and polygon. As an example, Fig 4 shows an embodiment of the present invention in a square PCB.

• Typically, LED is mounted at the centre of the segment.

• PCB circuit tracks run to each LED through the corridor area of flexible ring PCB.

• Number of zones is configured in the circuit according to the user requirement.

• It is also proposed to provide combination of various radial distances of LEDs by changing segment length as shown in Fig 2. • For easy adjustment of the angle, only one LED is exposed at a time. Others are masked during alignment.

• Once the angle alignment calibration is complete, thermally conductive adhesive or supporting potting compounds are used to fix the bent flexible segment.

• The flexible SMD lighting element board could be terminated by connectorizing, providing pads or connecting lugs, etc.

• In other embodiment of the present invention, in case flexible PCB does not have enough strength to hold for the bent configuration, backing sheets made of Aluminium, Beryllium Copper or similar rigid sheets are fixed to the flexible PCB to ensure its rigidity.

• In other embodiment of the present invention, once the angle of incidence of each LED is finalised, then angular backing supports are provided to the bent segments as shown in Fig 6.

• In other embodiment of the present invention, pre-designed peripheral backing supports are provided for the flexible PCB as shown in Fig 7. The peripheral backing support generally takes the geometry of the flexible PCB. Peripheral backing support for circular PCBs is given as example in the drawing. This invention can be applied in PCBs of any shapes, including but not limited to, circular, elliptical, . square, rectangular, polygon, etc.

• Connections may be in series, parallel, or combination of series and parallel in segments, as per current requirements.

• In the present invention, it is proposed that a provision for series resistors can also be provided in the segment.

• Number of zones as per requirement can be configured both mechanically and electrically.

• Yet another embodiment of the present invention is to provide collimators, lenses or optical elements to reduce the fan-out angle, thereby concentrating more light on the target object. Details of Parts

S.No. Part Name

1 Flexible PCB

2 Segment

3 LED

4 Resistor

5 Connectoriser

6 Corridor

7 Backing Sheet

8 Holder

9 Angular Backing support

10 Peripheral Backing support

Claims

Claims: I claim -

1. A Flexible Lighting Element for Vision Systems, consisting of a flexible PCB of pre determined shape, surface mount diodes and current limiting resistors, wherein the flexible PCB is demarcated into multiple zones that are further divided into bendable segments so as to enable the PCB to be bent at various required angles to produce different incident light angles while focussing light on the object of interest below the optics/camera, when the SMD LEDs and current limiting resistors are mounted on the segments at a specific (or different} radial distance(s) from the centre of the flexible PCB.

2. A Flexible Lighting Element for Vision Systems, consisting of flexible PCB of pre- determined shape, surface mount diodes and current limiting resistors, wherein it has multiple flexible PCBs with different radial distances, characterised in such a way that number of bendable segments are made in each zone of each PCB, so as to enable the. PCB to be bent at various required angles to produce different incident light angles while focussing light on the object of interest below the optics/camera, when the SMD LEDs arid current limiting resistors are mounted on the segments at different radial distances from the centre of the flexible PCB and further by placing the multiple PCBs concentrically, thereby providing enhanced focus lighting on the target object.

3. The Flexible Lighting Element accordingto the claims 1 & 2, wherein backingsheets made of Aluminium, Beryllium - Copper or similar rigid thermally conductive sheets is fixed to the flexible PCB to ensure rigidity of the flexible PCB to hold the bent configuration.

4. The Flexible Lighting Element according to claims 1 8c 2, wherein the bent flexible. segment is fixed to the flexible PCB using thermally conductive adhesive or supporting potting compounds, to prevent alteration in the angle of bend due to thermal expansion or contraction.

5. The Flexible Lighting Element according to claims 1 & 2, wherein pre-designed angular backing supports are fixed to the bent segments to prevent alteration in the angle of bend due to thermal expansion or contraction.

6. The Flexible Lighting Element according to claims 1 & 2, wherein pre-designed peripheral backing supports, according to the geometry of the flexible PCB, are fixed to the flexible PCBs to provide rigidity and prevent alteration in the angle of bend due to thermal expansion or contraction.

7. The Flexible Lighting Element according to claims 1 & 2, wherein collimators, lens or optical elements are additionally provided in the Flexible Lighting Element to reduce the fan-out angle, thereby concentrating more light on the target object.