RU2189523C2 - Light-emitting diode lighting unit - Google Patents

Abstract

FIELD: lighting engineering; light-emitting diode lighting units. SUBSTANCE: light-emitting diode lighting unit consists of set of elements including light-emitting diodes, condenser lens and diffuser raster lens. Light- emitting diodes located in front focus of condenser lens form parallel light beam at outlet which is deflected to required angle by means of diffuser lenses, thus ensuring required isocandle diagram. Light-emitting diodes are mounted in special frames for accurate positioning. Both lens rasters of optical system are secured to the same frame. Both lens rasters are made on optical surfaces of one diffuser. Heat-sinks made in form of metal bushes are located in each hole of frame. EFFECT: enhanced efficiency. 1 dwg

Description

 The invention relates to techniques for light signaling, in particular to LED lighting devices in which a plurality of light emitting diodes (LEDs) are mounted and held parallel to each other. The invention can be used in traffic lights used for traffic control, billboards and other similar lighting devices.

 Known devices according to [1, 2, 3], comprising a hollow cylindrical body having an opening at one end and a bottom at the other end, a mounting plate that is fixed along the middle inner periphery of the case, a plurality of LEDs installed in a plurality of mounting plate openings and outgoing from one surface. The LEDs are attached to the board by soldering two pins, so they can tilt during manual contact during the assembly process, which is the reason for the multidirectional projection of the light emitted by the LEDs and a decrease in their luminosity. It is necessary to create a lighting device in which the optical axis of the LEDs are mounted parallel to each other and coaxial with the optical systems with which they work to provide a unidirectional projection of light, thereby increasing the light output of the LEDs.

 For example, a lighting device according to [4] is known, which comprises a hollow cylindrical body having an opening at one end and a bottom at the other end, a mounting plate made in the form of a disk, which is placed in the middle part of the hollow body and fixed in diameter, and has many holes for installing the corresponding LEDs, a frame for LEDs, also made in the form of a disk fixed along the diameter of the housing and having many holes, in each of which there is a head of the corresponding light emitting diode rather than is provided by securing the optical axis of each light emitting diode in the same direction.

 The specified device has the following disadvantages: it does not have an optical system that forms the required distribution diagram of the light flux relative to the optical axis, and part of it is uselessly lost, not reaching the observers.

 A lighting device according to [5] is known, adopted by the applicant as a prototype, which comprises a circuit board on which a matrix of LEDs located on the optical axes is located in the focal planes of the condenser lens sections forming the first lens raster along the optical beam and an external diffuser , which is the second lens raster along the path of the optical beam. The number of lens sections of the external diffuser far exceeds the number of condenser lens sections equal to the number of LEDs. The lens sections of the external diffuser are made spherical.

 The prototype has the following disadvantages: the LEDs mounted (soldered) to the circuit board do not have a device for their exact centering relative to the optical system and because of this the light intensity of the entire lighting device is reduced and the required light distribution pattern is not provided. In addition, the coefficient of thermal expansion of the circuit board, as a rule, differs from the coefficient of thermal expansion of the external diffuser (lenses), which leads to additional decentration when the temperature changes.

 The objective of the invention is to increase the efficiency of the lighting device by creating the optimal (in accordance with the current standard [1]) distribution of the light flux.

 The problem is solved in the proposed LED lighting device containing a circuit board, on which a matrix of LEDs located on the optical axes is located in the focal planes of the condenser lens sections, forming the first lens raster along the optical beam and the external diffuser, which is the second along the way optical beam lens raster, and the number of lenses of the first lens raster is equal to the number of LEDs.

 The proposed device differs from the prototype in that it additionally introduces a device for positioning LEDs, made in the form of a frame having many holes, the number of which is equal to the number of LEDs, each of which houses the head of the corresponding LED, and the frame itself is rigidly connected with both lens rasters .

 A variant of the device is proposed, characterized in that both lens rasters are made on the optical surfaces of one diffuser.

 A device variant is proposed, characterized in that in each hole of the frame there is a radiator made in the form of a metal sleeve.

 The essence of the device is as follows: LED lighting device consists of a set of elements including an LED, a condenser lens and a raster lens of the diffuser. The LED located in the front focus of the condenser lens creates a parallel beam of light at the exit from it, which is deflected by the diffuser lenses to the required angle, providing the desired light distribution diagram. The LEDs are mounted in a special frame that ensures their accurate positioning. Both lens rasters of the optical system of the lighting device are attached to the same frame.

 A device variant containing two lens rasters irrationally uses part of the useful radiation, since at least 5% of the light is lost on each optical surface. A variant of the device in which the lens rasters are made on the optical surfaces of one optical part retains a greater amount of useful radiation, but is more complex and expensive to produce.

 The drawing shows an optical diagram of a variant of the proposed device, in which both lens rasters are made on the optical surfaces of one diffuser.

The positions in the drawing mean the following:
1 - mounting plate;
2 - matrix of LEDs;
3 - LED head;
4 - frame for LEDs;
5 - diffuser (two lens rasters);
6 - the first lens raster along the path of the optical beam;
7 - the second lens raster along the path of the optical beam;
8 - radiator.

 As shown in the drawing, the proposed lighting device comprises a matrix of LEDs 2 located on the optical axes in the focal planes of the condenser lenses forming the first lens raster 6 along the optical beam, and an external diffuser 7, which is the second lens raster along the optical beam. The number of condenser lens sections of the first raster 6 is equal to the number of LEDs in the matrix 2, and the number of lens sections of the external diffuser 7 is usually much larger than the number of condenser lens sections of the first raster 6. An additional device for positioning LEDs made in the form of a frame 4, having a plurality of holes, the number of which is equal to the number of LEDs, in each of which there is a head of the corresponding LED 3, and the frame itself is rigidly connected with both lens rasters, nennymi two optical surfaces one part - scatterer 5 (in this embodiment). In each hole of the frame there is a radiator 8, made in the form of a metal sleeve tightly covering the head of the LED 3.

 The device operates as follows. The matrix of LEDs 2 emits light. The first lens raster 6 creates a parallel light flux incident on the second lens raster 7, which creates an uneven distribution of light in the vertical and horizontal planes and also directs the radiation in the vertical plane up or down relative to the horizontal optical axis to the observer. The radiator 8 contributes to the rapid and uniform transfer of heat from the head of the LED 3 to the circuit board 1, which provides the cooling of its head 3 necessary for the operation of the LED.

Sources of information
1. US patent N 5038255.

 2. US Patent N 5119279.

 3. US patent N 5122939.

 4. U.S. Patent No. 5,400,229.

 5. Accepted application of Japan N 3-6601, publ. 01/30/91 (prototype).

Claims (1)

 An LED lighting device comprising a circuit board on which a matrix of LEDs located on the optical axes is placed in the focal planes of the condenser lens sections, forming the first lens raster along the optical beam and an external diffuser, which is the second lens raster along the optical beam, moreover, the number of lenses of the first lens raster is equal to the number of LEDs, characterized in that the device for positioning the LEDs, made in the form of a frame, is additionally introduced into it, and eyuschey plurality of apertures, each of which is disposed a radiator made of a metal sleeve, and the head of the corresponding LED, wherein the number of orifices equal to the number of LEDs and the frame itself is rigidly connected with the two lens rasters.