RU151161U1 - A WHITE LIGHT SOURCE AND A LAMP CONTAINING SUCH A SOURCE - Google Patents

Abstract

1. A white light source (1), comprising: a substrate (2) made of a material that does not conduct electric current, electrical conductors (3) formed on the surface of said substrate, a reflective layer (4) having a reflection coefficient higher than that of a substrate (2) located on said substrate (2), a transparent refractive layer (5) located on said reflective layer (4), a semiconductor chip (6) configured to emit light in the blue region of the light spectrum, electrically connected to said conductors (3) and located on said refractive layer (5), a layer (7) containing a phosphor emitting in the yellow region of the spectrum when excited by light from the blue region of the spectrum, an intermediate transparent layer (8) located around said semiconductor chip (6) and the refractive layer ( 5) and between said semiconductor chip (6) and a layer (7) containing a phosphor. 2. A source according to claim 1, characterized in that said reflection layer (4) has a reflection coefficient of more than 40%, preferably more than 50%, more preferably more than 60%, particularly preferably more than 70%, even more preferably more than 80%. . A source according to claim 1, characterized in that the area of said reflection layer (4) is larger than the area of said refractive layer (5) .4. A source according to claim 1, characterized in that said reflection layer (4) therein at least partially covers said electrical conductors (3) .5. A source according to claim 4, characterized in that said reflection layer (4) in it completely covers said electrical conductors (3) .6. A source according to claim 1, characterized by

Description

USEFUL MODEL

The utility model relates to the field of semiconductor white light sources.

BACKGROUND

White light emitting diodes are known in which a polymer coating containing a phosphor emitting yellow light is separated from a semiconductor chip emitting blue light by a thin transparent layer containing no phosphor (see, for example, Jong Kyu Kim, Hong Luo, Eric Fred Schubert, et al. Strongly Enhanced Phosphor Efficiency in GaInN White Light-Emitting Diodes Using Remote Phosphor Configuration and Diffuse Reflector Cup // Jpn. J. Appl. Phys. 2005, 44: L649-51, article by Hao-Chung Kuo, Cheng -Wei Hung, Hsin-Chu Chen, et al. Patterned structure of REMOTE PHOSPHOR for phosphor-converted white LEDs // OPTICS EXPRESS, 2011, 19 (S4): A930-6, as well as US Patent No. 8624281, figure 4). The presence of the interlayer allows to increase the luminosity of the LED by changing the path of the rays in the device and smooth out the negative effect of high temperature on the properties of the phosphor-containing coating.

Known semiconductor white light source based on a crystal of gallium nitride and phosphor, manufactured by planting the crystal in the housing and applying a layer of phosphor to its surface, while in order to increase the external quantum efficiency of the source, a thin layer coating with a refractive index of 1 is preliminarily applied, 9 ÷ 2.0 with a thickness of 50 ÷ 60 nm, then a polymer coating layer with a refractive index of 1.3 ÷ 1.4 with a thickness of 18 ÷ 200 nm, on top of which a phosphor layer is applied (RF patent for the invention 2472252).

A known white light emitting diode containing a blue light emitting element, coated on the outside with a layer of a gel-phosphor mixture to convert part of the blue radiation energy to yellow radiation energy and a transparent gel layer in which a transparent gel layer is applied directly to the light emitting element and the gel layer is the phosphor mixture is applied over a layer of a transparent gel and is made in the form of an aspherical lens with the ability to obtain a uniform white glow with the same color temperature regardless t of the angle of observation of LED radiation (RF patent for utility model No. 116602).

A known LED lamp containing a housing in the form of a box, on the bottom of which there are LEDs, the housing above the diodes is blocked by an opaque plate in which a hole is made, a plate with a phosphor deposited on it is installed in the hole, congruent to the hole, and a diffuser is located on top of the opaque plate, in which LEDs are mounted in a frame of reflective material and are fenced inside the case with vertical walls (RF patent for utility model No. 139412).

A common disadvantage of the above devices is the incomplete use of the total luminous flux of the chip, since known devices do not take into account that a significant part of the total luminous flux is emitted (or otherwise penetrates as a result of reflection / refraction / scattering) from the back of the chip towards the substrate and almost completely absorbed by the substrate and / or chip.

DISCLOSURE OF A USEFUL MODEL

The terms, expressions and abbreviations used in this text are given the following meaning:

A chip is a semiconductor device that emits light in the blue range of the light spectrum. As a rule, it consists of a dielectric substrate, for example, a sapphire substrate, and a layer of semiconductor material, in particular, based on gallium nitride.

Substrate - if it does not follow from the context that this is a chip substrate, “substrate” should be understood as a part on which one or more chips are placed. The substrate, as a rule, has a flat shape and is made of heat-resistant dielectric material.

Conductors - metal tracks or similar elements that conduct electric current, formed on the surface of the substrate, as a rule, by chemical etching.

The remaining terms and expressions are used in the usual sense known to those skilled in the art.

The objective of this utility model is to create a device with a combination of the following qualities:

- the efficiency is not lower than that of analogues having a phosphor layer separated from the chip by a layer of transparent material;

- use of the light flux emitted by the chip in the direction of the substrate. The technical result is as follows:

- improving the efficiency of use of the light flux emitted by the chip in the direction of the substrate,

- improved heat dissipation by reducing heat generated per unit area,

- due to the remote phosphor, reduce blue spectrum radiation to values as close as possible to an incandescent lamp,

- the absence of a glare effect, the possibility of reducing the luminous flux of less than 5 Lm / cm ² .

The above problem is solved due to the fact that the source (1) of white light contains:

a substrate (2) made of a material that does not conduct electric current, electrical conductors (3) formed on the surface of said substrate,

a reflecting layer (4) having a reflection coefficient higher than that of the substrate (2) located on said substrate (2),

a transparent refractive layer (5) located on said reflective layer (4),

a semiconductor chip (6) configured to emit light in the blue region of the light spectrum, electrically connected to said conductors (3), and located on said refracting layer (5),

a layer (7) containing a phosphor emitting in the yellow region of the spectrum when excited by light from the blue region of the spectrum,

an intermediate transparent layer (8) located around said semiconductor chip (6) and a refractive layer (5) and between said semiconductor chip (6) and a layer (7) containing a phosphor.

The reflection coefficient of the reflecting layer (4) can vary within wide limits. Preferably, when the reflectance of the reflective layer (4) is more than 40%, preferably more than 50%, even more preferably more than 60%, particularly preferably more than 70%, even more preferably more than 80%.

The area of said reflection layer (4) may be larger than the area of said refractive layer (5). It is also possible when said reflective layer (4) only partially covers said electrical conductors (3), or when a reflective layer (4) completely covers said electrical conductors (3).

In one particular embodiment of the source, the chip (6) is electrically connected to the conductors (3) via contact leads (9).

In another particular embodiment, the reflective layer (4) has technological holes in the junction of the contact leads (9) with electrical conductors (3) with a diameter of 0.1 ÷ 0.2 mm and a depth equal to the thickness of the reflective layer (4).

The thickness of the aforementioned intermediate transparent layer (8) can vary within wide limits. Preferably, when the thickness of said intermediate transparent layer (8) exceeds the total thickness of the reflective layer (4), the refractive layer (5) and the semiconductor chip (6), counting from the boundary of the transparent intermediate layer (8) with the substrate to the boundary of the transparent layer (8) with a layer (7) containing a phosphor. It is especially preferred that the thickness of the intermediate transparent layer (8) is at least 4.0 mm, counting from the boundary with the semiconductor chip (6) to the boundary with the layer (7) containing the phosphor.

The refractive index of said intermediate transparent layer (8) is preferably approximately 1.25 ÷ 1.4.

The intermediate transparent layer (8) in one of the preferred forms of execution can be formed in the form of a uniform coating of the reflective layer, while the said chip (6) is located inside it. Alternatively, the transparent layer (8) can be made in the form of a spherical or aspherical lens, and said chip (6) is located inside it.

In one particular embodiment, the refractive index of said transparent refractive layer (5) is about 1.6 ÷ 1.8.

In yet another particular embodiment, the edges of said transparent refractive layer (5) substantially coincide with the edges of the lower base of said chip (6).

In another particular embodiment, the thickness of said transparent refractive layer (5) is substantially a multiple of the wavelength of blue light emitted by the semiconductor chips (6).

In one particular embodiment, the thickness of said layer (7) containing the phosphor is 1.5 ÷ 2 mm, counting from the boundary with the transparent layer (8) to the boundary of the protective layer (11).

In another particular embodiment, the source may be further provided with a protective layer (11). The thickness of said protective layer (11) is preferably 0.5 to 1 mm.

The mentioned layer (7) containing the phosphor can be made in the form of a uniform coating of the intermediate transparent layer, while the chip (6) is located inside it. Alternatively, said phosphor-containing layer (7) may be in the form of a spherical or aspherical lens, with the chip (6) located inside it.

In one preferred embodiment, the surface of said chip (6) can, on one or both sides, be provided with an antireflection coating with a refractive index higher than that of the materials of said chip (6).

In one particularly preferred embodiment, said antireflection coating may have a refractive index of about 1.8 ÷ 2.0.

In yet another preferred embodiment, said antireflection coating may be a SiO or Ta ₂ O ₅ layer deposited by an ion-plasma method.

In another preferred embodiment, said antireflection coating has a thickness substantially equal to a quarter of the wavelength of blue light emitted by the crystal, and is approximately 50 ÷ 60 nm.

In one preferred embodiment, said substrate (2), a reflective layer (4), a refractive layer (5), a phosphor-containing layer (7), and an intermediate transparent layer (8) are heat-resistant.

In another preferred embodiment, said reflective layer (4), a refractive layer (5), a phosphor-containing layer (7), and an intermediate transparent layer (8) are made of a dielectric material.

The above problem is also solved due to the fact that the lamp contains at least two white light sources (1) described above, having a common substrate (2), a common layer (7) containing a phosphor emitting in the yellow region of the spectrum when excitation by light from the blue spectral region, and a common intermediate transparent layer (8) located around said semiconductor chips (6) and refractive layers (5) and between said semiconductor chip (6) and a layer (7) containing a phosphor.

In one of the preferred forms of execution, the lamp is additionally provided with a housing (10).

In one preferred embodiment, said body (10) is made of heat-resistant plasticized polyvinyl chloride.

In another preferred embodiment, said body (10) is coated on the inside with a reflective layer.

In another preferred embodiment, the luminaire is provided with an outer protective layer (11) configured to protect said layer (7) containing the phosphor from the action of negative environmental factors. In an even more preferred embodiment, said protective layer (11) is formed from a transparent gel-like compound.

In one preferred embodiment, said substrate (2) is fixed to a metal layer (12) made of copper or aluminum.

In another preferred embodiment, the area of said metal layer (12) is equal to the area of the substrate (2).

In another preferred embodiment, the thickness of said metal layer (12) is from 3 mm.

Further, the aforementioned device, characterized in general categories, is illustrated by the example of one of the specific forms of execution.

It must be understood that in this text the source and the lamp are characterized only by such signs that are sufficient to solve the task, implement the purpose and achieve the selected technical result; special mention of all the signs and utilitarian characteristics of the source and luminaire, without exception, is not required if specialists should be aware that products of the same kind possess such signs and utilitarian characteristics and without them the main purpose is not realized; all the more, it is not necessary to limit the generalized features to any specific options, if such should be known to specialists and (or) can be selected according to known rules.

The design and use of the source and the lamp is clearly illustrated by figures 1-3 on the example of private and specific embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

In FIG. 1 is a schematic sectional view of a white light source (1).

Positions 1-12 in the drawings indicate the following elements:

1 - light source

2 - substrate

3 - electrical conductors,

4 - reflective layer,

5 - transparent refractive layer,

6 - semiconductor chip,

7 is a layer containing a phosphor,

8 - intermediate transparent layer,

9 - contact conclusions

10 - case,

11 is a protective layer

11 - metal base.

IMPLEMENTATION OF A USEFUL MODEL

The proposed source (1) of white light, contains:

a substrate (2) made of a material that does not conduct electric current,

electrical conductors (3) formed on the surface of said substrate,

a reflecting layer (4) having a reflection coefficient higher than that of the substrate (2) located on said substrate (2),

a transparent refractive layer (5) located on said reflective layer (4),

a semiconductor chip (6) configured to emit light in the blue region of the light spectrum, electrically connected to said conductors (3), and located on said refracting layer (5),

a layer (7) containing a phosphor emitting in the yellow region of the spectrum when excited by light from the blue region of the spectrum,

an intermediate transparent layer (8) located around said semiconductor chip (6) and a refractive layer (5) and between said semiconductor chip (6) and a layer (7) containing a phosphor.

As shown in figure 1, the lamp contains at least two of the above white light sources, with a common substrate (2), a common layer (7) containing a phosphor emitting in the yellow region of the spectrum when excited by light from the blue region of the spectrum, and a common intermediate transparent layer (8) located around said semiconductor chips (6) and refractive layers (5) and between said semiconductor chip (6) and a layer (7) containing a phosphor.

The substrate (2) serves as a dielectric isolation between the aluminum base and copper printed conductors (3). It has a thickness of 50-150 microns and has the additional function of removing heat from crystals to an aluminum base.

Electrical copper conductors (3) have a gold-plated coating of the working surface and are designed to supply voltage through the contact leads (9) to the chips. The thickness of the copper conductors is 100-300 microns. The gold-plated coating of the elements is oxidation resistant and has good electrical conductivity. The large surface of copper conductors carries an additional function of heat removal from the crystals to the substrate (2).

The reflecting layer (4) has a coating thickness of 90-140 μm and is intended to form the necessary radiation pattern towards the working surface of the phosphor (7).

The transparent refractive layer (5) serves to redirect the light emitted from the lower base of the chip to the reflective layer (4).

The semiconductor chip (6) has an InGaN structure, characterized by radiation at a wavelength of 460-470 nm and serves as a source of blue light.

The layer (7) obtained by mixing silicate gel or epoxy resin with a phosphor serves to convert the blue spectrum emitted from the semiconductor chip (6) into white light. The area of the layer containing the phosphor (7) exceeds the area of the semiconductor chip by several tens of times.

The intermediate transparent layer (8) serves for uniform distribution of blue light emitted by the chip over the entire area of the layer containing the phosphor (7).

Contact pins (9) transfer the electric potential from electric copper conductors to the electrodes of the crystal (anode, cathode).

The housing (10), made of white PVC, serves to form the finished design of the light source (1). The inner surface of the housing is in direct contact with the reflective layer (4), the intermediate transparent layer (8) and the layer containing the phosphor (7). The inner surface, like the entire case, is smooth, white and has a high reflectivity. It also performs an additional function of reflection of blue light, in the direction of the layer containing the phosphor.

The protective layer (11) serves to protect the layer containing the phosphor (7) from the adverse effects of the external environment. It is made of a transparent heat-resistant gel-like material.

The metal base (12) is a cooling radiator when heat is removed from the substrate (2). The base is made of copper or aluminum.

The device operates as follows. Semiconductor chips (6) are uniformly located over the entire surface of the substrate (2). The number of LED chips (6) is determined by the area of the substrate (2), as well as by the design and power of the LED module (1) assembly. Between the semiconductor chips (6) and the reflective layer (4) is an ultrathin transparent refractive layer (5), which has a high light refractive index. The area of the transparent refractive layer (5) coincides with the area of the lower base of the semiconductor chips (6). Under the reflective layer (4) are electrical conductors (3), which are designed to supply voltage through the contact leads (9) to the semiconductor chips (6). At the junction of the contact leads (9) with electrical conductors (3) there are technological holes in the reflective layer (4). Electrical conductors (3) are mounted on a dielectric substrate (2). Electrical conductors (3) and substrate (2) perform an additional function of heat removal from semiconductor chips (6). In turn, the substrate (2) is mounted on a metal base (12), which is made of copper or aluminum. The metal base (12) performs the function of removing heat from the substrate (2). This design is placed in the housing (10), which is made of white, with a high reflection coefficient of heat-resistant material. The inner part of the housing (10) is filled with an intermediate transparent layer (8). A layer containing a phosphor (7) is applied over the intermediate transparent layer (8). The phosphor layer (7) is covered with a protective layer (11), made of a transparent heat-resistant gel-like material.

When voltage is applied to the module, the semiconductor chips (6) emit blue light. Light emits from the entire surface area of semiconductor chips (6). The emitted blue light from the upper surface of the LED chips (6) passes through the intermediate transparent layer (8) and, falling onto the layer containing the phosphor (7), activates its glow, resulting in white light at the output. Blue light from the side surface of the LED chips (6) due to the design and material of the housing (10), as well as the reflective layer (4), is reflected and rushes towards the layer containing the phosphor (7). Blue light from the bottom of the semiconductor chip passes through a thin transparent refracting layer (5), then it hits the reflective layer (4) and is reflected towards the layer containing the phosphor (7).

This LED module provides the return of blue radiation reflected from the reflecting layer and the layer containing the phosphor back to the surface of the remote phosphor, providing repeated interaction of blue radiation with the phosphor and the exit of white light to the useful part of the module. Thanks to the fixation scheme of the semiconductor chip on the reflective coating, using the refractive layer, there is an effective use of all emitted light by the semiconductor chip.

Claims (35)

1. A white light source (1), comprising: a substrate (2) made of a material that does not conduct electric current, electrical conductors (3) formed on the surface of said substrate, a reflecting layer (4) having a reflection coefficient higher than that of the substrate (2) located on said substrate (2), a transparent refractive layer (5) located on said reflective layer (4), a semiconductor chip (6), configured to emit light in the blue region of the light spectrum, electrically connected to said conductors (3) and located on said refractive layer (5), a layer (7) containing a phosphor emitting in the yellow region of the spectrum when excited by light from the blue region of the spectrum, an intermediate transparent layer (8) located around said semiconductor chip (6) and a refractive layer (5) and between said semiconductor chip (6) and a layer (7) containing a phosphor. 2. A source according to claim 1, characterized in that said reflection layer (4) has a reflection coefficient of more than 40%, preferably more than 50%, more preferably more than 60%, particularly preferably more than 70%, even more preferably more than 80% . 3. A source according to claim 1, characterized in that the area of said reflection layer (4) is larger than the area of said refractive layer (5). 4. A source according to claim 1, characterized in that said reflection layer (4) in it at least partially covers said electrical conductors (3). 5. A source according to claim 4, characterized in that said reflection layer (4) in it completely covers said electrical conductors (3). 6. The source according to claim 1, characterized in that in it the chip (6) is electrically connected to the conductors (3) by means of contact leads (9). 7. A source according to claim 6, characterized in that said reflecting layer (4) has technological holes in the junction of the contact leads (9) with electrical conductors (3) with a diameter of 0.1 ÷ 0.2 mm and a depth equal to the thickness of the reflective layer (4). 8. A source according to claim 1, characterized in that the thickness of said intermediate transparent layer (8) exceeds the total thickness of the reflective layer (4), the refractive layer (5) and the semiconductor chip (6), counting from the boundary of the transparent intermediate layer ( 8) with a substrate up to the boundary of the transparent layer (8) with the layer (7) containing the phosphor. 9. A source according to claim 1, characterized in that the thickness of said intermediate transparent layer (8) is at least 4.0 mm, counting from the boundary with the semiconductor chip (6) to the boundary with the layer (7), containing phosphor. 10. A source according to claim 1, characterized in that the refractive index of said intermediate transparent layer (8) is approximately 1.25 ÷ 1.4. 11. A source according to claim 1, characterized in that said intermediate transparent layer (8) is made in the form of a uniform coating of the reflective layer, and said chip (6) is located inside it. 12. A source according to claim 1, characterized in that said intermediate transparent layer (8) is made in the form of a spherical or aspherical lens, and said chip (6) is located inside it. 13. A source according to claim 1, characterized in that the refractive index of said transparent refractive layer (5) is approximately 1.6 ÷ 1.8. 14. A source according to claim 1, characterized in that in it the edges of said transparent refractive layer (5) substantially coincide with the edges of the lower base of said chip (6). 15. A source according to claim 1, characterized in that the thickness of said transparent refractive layer (5) is substantially a multiple of the wavelength of blue light emitted by semiconductor chips (6). 16. The source according to claim 1, characterized in that the thickness of said layer (7) containing the phosphor is 1.5–2 mm thick, counting from the boundary with the transparent layer (8) to the boundary of the protective layer (11). 17. A source according to claim 1, characterized in that it further comprises an outer protective layer (11). 18. The source according to claim 17, characterized in that the thickness of said protective layer (11) is 0.5 ÷ 1 mm. 19. A source according to claim 1, characterized in that said layer (7) containing a phosphor is made in the form of a uniform coating of an intermediate transparent layer, wherein the chip (6) is located inside it. 20. A source according to any one of Claims 1, characterized in that said layer (7) containing a phosphor is made in the form of a spherical or aspherical lens, wherein the chip (6) is located inside it. 21. A source according to claim 1, characterized in that in it the surface of said chip (6) is additionally provided on one or both sides with an antireflection coating with a refractive index higher than that of the materials of said chip (6). 22. The source according to p. 21, characterized in that it said antireflection coating has a refractive index of approximately 1.8 ÷ 2.0. 23. The source according to p. 21, characterized in that it said antireflection coating is a layer of SiO or Ta ₂ O ₅ deposited by the ion-plasma method. 24. A source according to any one of paragraphs. 21-23, characterized in that the aforementioned antireflection coating therein has a thickness substantially equal to a quarter of the wavelength of blue light emitted by the crystal and approximately 50 ÷ 60 nm. 25. The source according to claim 1, characterized in that the said substrate (2), the reflective layer (4), the refractive layer (5), the layer (7) containing the phosphor, and the intermediate transparent layer (8) are heat-resistant. 26. A source according to claim 1, characterized in that said reflective layer (4), a refractive layer (5), a layer (7) containing a phosphor, and an intermediate transparent layer (8) are made of dielectric material. 27. A luminaire containing at least two white light sources (1) according to any one of paragraphs. 1-26 having a common substrate (2), a common layer (7) containing a phosphor emitting in the yellow region of the spectrum when excited by light from the blue spectral region, and a common intermediate transparent layer (8) located around said semiconductor chips (6) and refractive layers (5) and between said semiconductor chip (6) and a layer (7) containing a phosphor. 28. The lamp according to claim 27, characterized in that it is additionally equipped with a housing (10). 29. A luminaire according to claim 27, characterized in that said housing (10) is made of heat-resistant plasticized polyvinyl chloride in it. 30. A luminaire according to claim 27, characterized in that said housing (10) is coated on the inside with a reflective layer. 31. A luminaire according to claim 27, characterized in that said housing (10) therein is additionally provided with an external protective layer (11) configured to protect said layer (7) containing a phosphor from the action of negative environmental factors. 32. A luminaire according to claim 27, characterized in that said protective layer (11) is made of a transparent gel-like compound in it. 33. A luminaire according to claim 27, characterized in that said substrate (2) therein is fixed on a metal layer (12) made of copper or aluminum. 34. A luminaire according to claim 27, characterized in that the area of said metal layer (12) is equal to the area of the substrate (2). 35. A luminaire according to claim 27, characterized in that the thickness of said metal layer (12) is from 3 mm.

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