CN121336070A - Light-emitting device with lens array - Google Patents

Abstract

A light emitting device (1) comprising a light emitting element array (2) configured to emit light in a main emission direction (M) in operation, and a lens array (3) arranged to cover at least a part of the light emitting element array (2), wherein each lens of the lens array (3) is arranged to cover light emitting elements of the light emitting element array (2), wherein each lens of the lens array (3) is a free-form surface lens, and wherein the lens array (3) comprises a plurality of first lenses (31) and a plurality of second lenses (32), the plurality of first lenses (31) being configured such that light emitted by the light emitting elements is directed in a first direction (D1) different from the main emission direction (M), the plurality of second lenses (32) being configured such that light emitted by the light emitting elements is directed in a second direction (D2) different from the main emission direction (M), the first direction (D1) being different from the second direction (D2).

Description

Light emitting device with lens array

Technical Field

The invention relates to a light emitting device comprising an array of light emitting elements configured to emit light in a main emission direction in operation, and an array of lenses arranged to cover at least a part of the array of light emitting elements, wherein each lens of the array of lenses is arranged to cover a light emitting element of the array of light emitting elements. The invention also relates to a luminaire or lamp comprising such a light emitting device.

As used herein, the term "2D color gradient" is intended to mean a color gradient that exists in two mutually different directions simultaneously when viewed on the surface of a target.

Background

With the introduction of pixelated luminaires (e.g. tonal gradient signals), consumers are now able to present a gradient light pattern on e.g. a wall. However, these gradients are defined as 1D, i.e. there are only gradients in the light pattern in one direction, i.e. in the same direction as the main orientation of the LED strip.

US2019/326350A1 discloses a source sensitive optic using a reconfigurable chip-on-board (CoB) Light Emitting Diode (LED) array as a light source. The reconfigurable CoB LED array includes a predetermined number of LEDs that are configurable for various lighting conditions. The reconfigurable CoB LED array may be a plurality of CoB LED arrays configured for use with source-sensitive optics. The source sensitive optics include a surface shape responsive to the reconfigurable CoB LED array. The source sensitive optics are configured to provide beam profile and radiation pattern differences based on a CoB LED array configuration configured by reconfigurable CoB LEDs. Due to the proximity and geometry of the surface shape, each configurable CoB LED array configuration radiates a different beam pattern through the surface shape.

In current pixelated LED strips, a smooth color gradient is possible by varying the spectrum of the LEDs along the major axis of the strip, as shown in fig. 1. However, another color change or gradient cannot be made, for example in a direction orthogonal to the smooth color gradient.

It is therefore desirable to provide a light emitting device with which different color gradients can be generated simultaneously in at least two different directions when seen on a target surface such as a wall or a ceiling.

Disclosure of Invention

It is an object of the present invention to overcome this problem and to provide a light emitting device with which it is possible to simultaneously produce different color gradients in at least two mutually different directions when seen on a target surface such as a wall or a ceiling.

According to a first aspect of the invention, this and other objects are achieved by a light emitting device comprising an array of light emitting elements configured to emit light in a main emission direction in operation, and an array of lenses arranged to cover at least a part of the array of light emitting elements, wherein each lens of the array of lenses is arranged to cover a light emitting element of the array of light emitting elements, wherein each lens of the array of lenses is a free-form surface lens. And wherein the lens array comprises a plurality of first lenses configured to cause light emitted by the light emitting element to be directed in a first direction different from the main emission direction and a plurality of second lenses configured to cause light emitted by the light emitting element to be directed in a second direction different from the main emission direction, wherein the first direction is different from the second direction.

Thus, and in particular by providing a lens array comprising a plurality of first lenses configured such that light emitted by the light emitting element is directed in a first direction different from the main emission direction and a plurality of second lenses configured such that light emitted by the light emitting element is directed in a second direction different from the main emission direction, wherein the first direction is different from the second direction, a light emitting device is provided with which two different color gradients can be produced simultaneously when seen on a target surface such as a wall or a ceiling.

In particular, such a light emitting device is capable of using a 1D or 2D array of light emitting elements to produce a light output with a 2D color gradient. Typically, in the case of use, the target surface is located within a distance of 0.5m to 1m from the light emitting device.

The lenses of the plurality of first lenses and the lenses of the plurality of second lenses may be alternately arranged in a lens array.

Thus, a particularly well-defined color gradient can be obtained.

The lenses of the plurality of first lenses and the lenses of the plurality of second lenses may include mutually different surface profiles.

In addition to the fact that different color gradients can generally be produced in a particularly simple manner, such mutually different surface contours provide a particularly simple manner of changing or tailoring the color gradient, i.e. by selecting a particular predefined surface contour.

The plurality of first lenses may be free-form surface lenses configured to collimate light emitted by the light emitting element, and the plurality of second lenses may be free-form surface lenses configured to include a peanut shape.

It has been shown that providing such a free-form surface lens is particularly suitable for providing a light output with a well-defined 2D color gradient.

The plurality of second lenses may be configured to direct a major portion of the light emitted by the light emitting element at a beam angle between 40 degrees and 65 degrees with respect to the main emission direction.

The plurality of first lenses may be configured to provide a first beam angle for light emitted by the light emitting element, the plurality of second lenses may be configured to provide a second beam angle for light emitted by the light emitting element, and the first beam angle is less than the second beam angle.

The first beam angle may be at least 2x 10 degrees, or at least 2x 15 degrees, or at least 2x 20 degrees less than the second beam angle.

The first beam angle may be 2 x 45 degrees or 2 x 50 degrees or 2 x 55 degrees and the second beam angle may be 2 x 60 degrees or 2 x 65 degrees or 2 x 70 degrees.

Such values of the individual beam angles and/or the relation between them have been shown to be particularly suitable for producing a light output with a well-defined 2D color gradient in typical use situations, wherein the target surface is located within a distance of 0.5m to 1m from the light emitting device.

The light emitted by the light emitting elements of the array of light emitting elements may comprise a variable color spectrum.

Thus, the 2D color gradient of the light output can be controlled by varying the color spectrum of the light emitted by the light emitting element. This may be done before, during and after manufacturing the light emitting device, e.g. at the end user and by the end user in an installed condition.

The light emitted by the light emitting elements covered by the plurality of first lenses may have a first color spectrum, the light emitted by the light emitting elements covered by the plurality of second lenses may have a second color spectrum, and the first color spectrum is different from the second color spectrum.

The first color spectrum may be different from the second color spectrum, for example, in color, brightness, or a combination thereof. The difference between the first and second chromatograms can be measured by measuring the amount of change E orTo represent it is a standard measure of the difference between two colors appearing on a quantized screen or target surface.The level is the difference between the display color of the input content and the original color standard. Lower and lowerRepresenting smaller differences and higherThe level indicates a large difference.The values are expressed on a scale from 0 (no difference) to 100 (representing diametrically opposite colors (e.g., black and white or red and green)). In the present case, therefore,The difference between the first and second chromatograms is quantified as occurring on the target surface.

A particularly well-defined color gradient can thereby be produced in both directions, as is shown for example in fig. 5 and 7.

The light emitting device may further comprise a controller configured to individually control the color spectrum of light emitted by the light emitting elements of the array of light emitting elements.

Thus, even after the light emitting device has been manufactured, e.g. at and by the end user in an installed condition, the 2D color gradient of the light output can be controlled.

The light emitting element array and the lens array may be arranged on the substrate.

The array of light emitting elements may form a LED strip.

The array of light emitting elements may be a two-dimensional array of light emitting elements.

The light emitting device may further comprise a diffuser plate arranged over the array of light emitting elements.

The light emitting device may further include a housing in which the light emitting element array and the lens array are arranged.

Therefore, the light emitting element and the lens array are effectively protected from external influences such as dust.

The invention also relates to a luminaire comprising at least one light emitting device according to any one of the preceding claims.

It should be noted that the invention relates to all possible combinations of features recited in the claims.

Drawings

This and other aspects of the invention will now be described in more detail, with reference to the appended drawings showing embodiments of the invention.

Fig. 1 shows the light pattern of a prior art light emitting device seen on the surface of a target.

Fig. 2 shows a perspective view of a light emitting device according to the invention.

Fig. 3 shows a perspective view of an enlarged cross section of the light emitting device according to fig. 2.

Fig. 4 shows a cross-sectional view of a cross-section of the light emitting device according to fig. 2 seen in plane IV shown in fig. 3.

Fig. 5 shows the light pattern of a light emitting device according to the invention seen on the surface of a target.

Fig. 6 shows a simulation of the illuminance and color of light emitted by a light emitting device according to the invention as seen on the target surface, showing that a uniform color band can be manufactured with a light emitting device according to the invention.

Fig. 7 shows a simulation of the illuminance and color of light emitted by a light emitting device according to the invention seen on the surface of a target, showing that a plurality of gradients, both vertical and horizontal, can be manufactured with a light emitting device according to the invention.

Fig. 8 shows a schematic cross-sectional view of a luminaire comprising a light emitting device according to the invention.

As shown, the dimensions of the layers and regions are exaggerated for purposes of illustration and are therefore provided to illustrate the general structure of embodiments of the present invention. Like numbers refer to like elements throughout.

Detailed Description

The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which currently preferred embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather should be construed in order to be thorough and complete, and will fully convey the scope of the invention to the skilled artisan.

Referring to fig. 2 to 4, an embodiment of the light emitting device 1 according to the present invention will now be described. The light emitting device 1 generally comprises a light emitting element array 2 and a lens array 3.

The light emitting element array 2 is configured to emit light in a main emission direction M in operation, see fig. 4. The light emitting elements 21, 22 of the light emitting element array 2 may be configured to emit light having a variable color spectrum. The light emitting element array 2 may be a one-dimensional (1D) array as shown in fig. 1. Alternatively, the light emitting element array 2 may be a two-dimensional (2D) array. In the former case, the light emitting element array 2 may form an LED strip. In the latter case, any size of the array is in principle possible.

The light emitting device 1 is configured to provide a light output in operation. The light output of the light emitting device 1 is a combination of light emitted by all light emitting elements of the light emitting element array 2.

The lens array 3 is arranged to cover at least a portion of the light emitting element array 2. Each lens of the lens array 3 is arranged so as to cover the light emitting elements of the light emitting element array 2. Each lens of the lens array 3 is a free-form surface lens.

The lens array 3 includes a plurality of first lenses 31, the plurality of first lenses 31 being configured such that light emitted by the light emitting elements 2 covered by the lenses 31 is directed in a first direction D1, see fig. 3 and 4. The first direction D1 is different from the main emission direction M. The lenses of the plurality of first lenses 31 comprise a first surface profile 33, see fig. 4. The plurality of first lenses 31 may be free-form surface lenses configured to collimate light emitted by the light emitting element 2 covered by a lens of the plurality of first lenses 31. The plurality of first lenses 31 are configured to provide a first beam angle A1 for light emitted by the light emitting element, see fig. 4. The first beam angle A1 may be 2 x 45 degrees or 2 x 50 degrees or 2 x 55 degrees.

Some of the light emitting elements 21 of the light emitting element array 2 are covered with lenses of the plurality of first lenses 31. The light emitted by the light emitting elements 21 covered by the plurality of first lenses 31 may have a first color spectrum.

The lens array 3 further comprises a plurality of second lenses 32, the plurality of second lenses 32 being configured such that light emitted by the light emitting elements 2 covered by the lenses 32 is directed in a second direction D2, see fig. 3 and 4. The second direction D2 is different from the main emission direction M. Further, the second direction D2 is different from the first direction D1. The lenses of the plurality of second lenses 32 comprise a second surface profile 34, see fig. 4. The second surface profile 34 is different from the first surface profile 33. The plurality of second lenses 32 may be free-form surface lenses configured to include a peanut shape. The plurality of second lenses are configured to direct a major portion of the light emitted by the light emitting element at a second beam angle A2, see fig. 4. The second beam angle A2 may be between 40 degrees and 65 degrees with respect to the main emission direction M. The second beam angle A2 may be 2 x 60 degrees or 2 x 65 degrees or 2 x 70 degrees.

Some of the light emitting elements 22 of the light emitting element array 2 are covered by lenses of the plurality of second lenses 32. The light emitted by the light emitting elements 22 covered by the plurality of second lenses 32 may have a second color spectrum. The second color spectrum is different from the first color spectrum.

The second beam angle A2 is greater than the first beam angle A1. In other words, the first beam angle A1 is smaller than the second beam angle A2. For example, the first beam angle A1 is at least 2×10 degrees, or at least 2×15 degrees, or at least 2×20 degrees smaller than the second beam angle A2.

The lenses of the plurality of first lenses 31 and the lenses of the plurality of second lenses 32 are alternately arranged in the lens array 3 as shown in fig. 3.

Referring specifically to fig. 2, the light emitting device 1 may optionally further comprise a controller 7. The controller 7 is configured to individually control the light emitting elements of the light emitting element array 2, in particular to individually control the color spectrum of the light emitted by the light emitting elements of the light emitting element array 2.

Referring specifically to fig. 3 and 4, the light emitting element array 2 and the lens array 3 may be optionally arranged on the substrate 4. The substrate 4 may be, for example, a printed circuit board. The substrate 4 may comprise wires configured to provide electrical energy to the light emitting element 2. The substrate 4 may further comprise a connection element configured to connect the electrical wire to an electrical energy source, such as mains.

With particular reference to fig. 3 and 4, the light emitting device 1 may also optionally comprise a diffuser plate 6. A diffuser plate 6 is arranged above the array of light emitting elements 2. The diffuser plate 6 may be arranged at the light exit surface of the light emitting device 1 or form the light exit surface of the light emitting device 1. The diffuser plate 6 may comprise one or more of a light outcoupling structure and a diffractive structure.

Referring specifically to fig. 2 and 3, the light emitting device 1 may further optionally include a housing 5, the light emitting element array 2 and the lens array 3 being arranged in the housing 5. As shown in fig. 2, the housing 5 may include a bottom surface 51, a top surface 52, and a circumferential sidewall 53 connecting the bottom surface 51 and the top surface 52. The inner surface 54 (see fig. 3) of the circumferential wall 53 facing the array of light emitting elements 2 may be provided with a reflective layer or coating or made of a reflective material. The base plate 4 may also be arranged in the housing 5, if provided. Alternatively, the substrate 4 may form the bottom surface 51 of the housing 5. Where provided, the diffuser plate 6 may be disposed at the upper surface 52 of the housing 5 or form the upper surface 52 of the housing 5.

Turning now to fig. 5, a light pattern of a light emitting device 1 according to the invention is shown as seen on a target surface such as a wall or a ceiling. In this example, the first type of lens 31 of the lens array 3 is a free-form surface lens that collimates light from the light emitting element 21 in a straight direction to obtain a beam angle A1 of 2×50 degrees. The second type of lens 32 of the lens array 3 is a free-form surface lens having a peanut shape configured to collimate the light from the light emitting element 22 in an outward direction to obtain a beam angle A2 of 2 x 65 degrees, with a majority of the light being directed within the beam angle A2 of 40 degrees to 65 degrees. By placing these lenses 31 and 32 in an alternating order on the light emitting elements of the light emitting element array 2 and by varying the color spectrum of the light emitted by the light emitting elements 21 and 22, respectively, as shown in fig. 5, 2D color gradients, i.e. color gradients G1 and G2, respectively, can be generated in two mutually different, here orthogonal, directions.

Fig. 6 shows a simulation of the illuminance and color of light emitted by the light emitting device 1 according to the invention, as described above in connection with fig. 5, as seen on the target surface. Fig. 6 shows that a uniform color band can be manufactured with the light emitting device 1 according to the invention. For example, a color gradient is introduced under both types of lenses to the light emitted by the light emitting elements 21 and 22, respectively, such as, for example, green to red for the light emitted by the light emitting element 22 under the second type of lens 32 and blue to green for the light emitted by the light emitting element 21 under the first type of lens 31. In this way, a 2D change in color can be obtained. Thereby, the light emitting device 1 serving as a uniform color band is provided.

Fig. 7 shows a simulation of the illuminance and color of light emitted by the light emitting device 1 according to the invention, as described above in connection with fig. 5, as seen on the target surface. Fig. 7 shows that a plurality of gradients (see G1 and G2 in fig. 5) can also be obtained both vertically and horizontally with the light emitting device 1 according to the invention. Thus, 2D color gradients are obtained, i.e. color gradients G1 and G2 in two mutually different, here orthogonal, directions, respectively.

It should be noted that fig. 6 and 7 are black and white reproductions of the actual full color result of the simulation. For example, in fig. 7, the actual situation is from top to bottom, with a color gradient from green through cyan to blue.

Finally, fig. 8 shows an exemplary luminaire or lamp 12 comprising a light emitting device 1 according to any embodiment of the invention. In the embodiment shown, the light emitting device 1 may in this case be configured or formed as a substantially straight LED filament. In other embodiments, the light emitting device 1 of such a lamp may be an LED filament having other shapes, such as, but not limited to, spiral, helical, meander, twist, flat, and combinations thereof. In this embodiment, the light emitting device 1 does not comprise any housing 5 or diffuser plate 6.

The lamp 12 further comprises a driver or controller 17 configured for controlling the array of light emitting elements 2 of the light emitting device 1. The controller 17 is configured to supply power to the light emitting element array 2 via the circuit of the light emitting device 1. The controller 17 may also be configured to control at least one of the CCT of the light emitted by the light emitting device and the CRI of the light emitted by the light emitting device. The controller 17 may also be configured for controlling other parameters related to the array of light emitting elements 2 and the light emitted by the light emitting device.

The lamp 12 further comprises an envelope 13 at least partly enclosing the at least one light emitting device 1. The lamp 12 further comprises a cap 14. As shown in fig. 8, the controller 17 is disposed within the enclosure 13. When the cap 14 is included, the controller 17 may also be disposed inside the cap 14 such that it is hidden from view. The lamp 12 further comprises a screw thread 15 for connection to a socket and a terminal 16 for connection to an electrical energy source.

The envelope 13 of the lamp 12 may also and optionally be provided with a coating 18, such as a reflective coating or a diffuse coating, covering at least a portion of the envelope 13.

Note that the luminaire or lamp 12 shown in fig. 8 is only one example of a luminaire according to the invention. Any suitable type of luminaire is contemplated, such as, but not limited to, a luminaire shaped as a light strip or a square luminaire. In the former case, the light emitting device 1 may comprise an array of light emitting elements 2, which may be configured or formed as a one-dimensional array of light emitting elements 2. In the latter case, the light emitting device 1 may comprise an array of light emitting elements 2, which may be configured or formed as a two-dimensional array of light emitting elements 2.

Pendant type fixtures, vertical type fixtures, wall-mounted fixtures, ceiling-mounted fixtures, chandeliers, reading fixtures, outdoor fixtures, and watch fixtures are also possible.

The person skilled in the art realizes that the present invention by no means is limited to the preferred embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

Further, variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims (14)

1. A light emitting device (1), comprising:

an array of light emitting elements (2) configured to emit light in a main emission direction (M) in operation, an

A lens array (3) arranged to cover at least a part of the array of light emitting elements, wherein

Each lens of the lens array (3) is arranged so as to cover a light emitting element of the light emitting element array, wherein

Each lens of the lens array (3) is a free-form surface lens, and wherein

The lens array (3) comprises a plurality of first lenses (31) and a plurality of second lenses (32), the plurality of first lenses (31) being configured such that the light emitted by the light emitting element is directed in a first direction (D1) different from the main emission direction (M), the plurality of second lenses (32) being configured such that the light emitted by the light emitting element is directed in a second direction (D2) different from the main emission direction (M), wherein the first direction (D1) is different from the second direction (D2),

Wherein the lenses of the plurality of first lenses (31) and the lenses of the plurality of second lenses (32) are alternately arranged in the lens array, and

Wherein the plurality of first lenses (31) are free-form surface lenses configured to collimate the light emitted by the light emitting element.

2. A light emitting device according to claim 1, wherein the lenses of the plurality of first lenses (31) and the lenses of the plurality of second lenses (32) comprise mutually different surface profiles (33; 34).

3. The light emitting device according to any one of the preceding claims, wherein the plurality of second lenses (32) are free-form surface lenses configured to comprise a peanut shape.

4. The light emitting device according to any one of the preceding claims, wherein the plurality of second lenses (32) are configured to direct a major portion of the light emitted by the light emitting element at a beam angle (A2) of between 40 degrees and 65 degrees with respect to the main emission direction (M).

5. The light emitting device according to any of the preceding claims, wherein the plurality of first lenses (31) is configured to provide a first beam angle (A1) for light emitted by the light emitting element, wherein the plurality of second lenses (32) is configured to provide a second beam angle (A2) for light emitted by the light emitting element, and wherein the first beam angle (A1) is smaller than the second beam angle (A2).

6. The light emitting device according to claim 5, wherein the first beam angle (A1) is at least 2x 10 degrees, or at least 2x 15 degrees, or at least 2x 20 degrees smaller than the second beam angle (A2).

7. The light emitting device according to claim 5 or 6, wherein the first beam angle (A1) is 2 x 45 degrees or 2 x 50 degrees or 2 x 55 degrees, and wherein the second beam angle (A2) is 2 x 60 degrees or 2 x 65 degrees or 2 x 70 degrees.

8. A light emitting device according to any of the preceding claims, wherein the light emitted by the light emitting elements of the array of light emitting elements (2) comprises a variable color spectrum.

9. The light emitting device according to any of the preceding claims, wherein the light emitted by the light emitting elements (21) covered by the plurality of first lenses (31) has a first color spectrum, wherein the light emitted by the light emitting elements (22) covered by the plurality of second lenses (32) has a second color spectrum, and wherein as a function of the amount of change E #) The first chromatograph is different from the second chromatograph as quantified.

10. A light emitting device according to any of the preceding claims, further comprising a controller (7), the controller (7) being configured to individually control a color spectrum of the light emitted by the light emitting elements of the array of light emitting elements (2).

11. A light emitting device according to any of the preceding claims, wherein the array of light emitting elements (2) and the array of lenses (3) are arranged on a substrate (4).

12. The light emitting device according to any of the preceding claims, wherein the array of light emitting elements (2) forms a LED strip,

Wherein the array of light emitting elements (2) is a two-dimensional array of light emitting elements.

13. A light emitting device according to any one of the preceding claims, and further comprising one or more of the following:

A diffuser plate (6) arranged above the array of light emitting elements, and

A housing (5) in which the light emitting element array and the lens array are arranged.

14. A luminaire comprising at least one light emitting device (1) according to any one of the preceding claims.