Phosphor plate and lighting device

A phosphor plate may be provided that includes a base plate transmitting light; and a lens being disposed on at least one of both surfaces of the base plate and including a fluorescent material.

CROSS-REFERENCE TO RELATED APPLICATION

BACKGROUND

Embodiments may relate to a phosphor plate and lighting device.

A light emitting diode (LED) is an energy device for converting electric energy into light energy. Compared with an electric bulb, the LED has higher conversion efficiency, lower power consumption and a longer life span. As there advantages are widely known, more and more attentions are now paid to a lighting apparatus using the LED.

The lighting apparatus using the LED are generally classified into a direct lighting apparatus and an indirect lighting apparatus. The direct lighting apparatus emits light emitted from the LED without changing the path of the light. The indirect lighting apparatus emits light emitted from the LED by changing the path of the light through reflecting means and so on. Compared with the direct lighting apparatus, the indirect lighting apparatus mitigates to some degree the intensified light emitted from the LED and protects the eyes of users.

SUMMARY

One embodiment is a phosphor plate. The phosphor plate includes: a base plate transmitting light; and a lens being disposed on at least one of both surfaces of the base plate and including a fluorescent material.

Another embodiment is a lighting device. The lighting device includes: a case including a recess; a light emitting module being disposed in the recess of the case and including at least one light emitting device; and a phosphor plate being disposed in the recess of the case and being disposed over the light emitting module. The phosphor plate includes a base plate transmitting light and a lens being disposed on at least one of both surfaces of the base plate and including a fluorescent material.

DETAILED DESCRIPTION

A thickness or a size of each layer may be magnified, omitted or schematically shown for the purpose of convenience and clearness of description. The size of each component may not necessarily mean its actual size.

It should be understood that when an element is referred to as being ‘on’ or “under” another element, it may be directly on/under the element, and/or one or more intervening elements may also be present. When an element is referred to as being ‘on’ or ‘under’, ‘under the element’ as well as ‘on the element’ may be included based on the element.

An embodiment may be described in detail with reference to the accompanying drawings.

FIG. 1is a perspective view of a phosphor plate according to a first embodiment.FIG. 2is a cross sectional view of the phosphor plate shown inFIG. 1taken along a line A-A′.

Referring toFIGS. 1 to 2, when a phosphor plate100according to a first embodiment receives predetermined light incident from the outside, the phosphor plate100is able to emit excited light by the incident light. The phosphor plate100is also able to transmit the incident light as it is. The light emitted from the phosphor plate100may be created by adding the incident light and the excited light.

The phosphor plate100may include a base plate110and a plurality of lenses130.

The base plate110may be a polymer plate capable of transmitting light. The base plate110may be, for example, any one selected from a group consisting of polycarbonate (PC), a light guide plate, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), acrylic resin, polystyrene (PS), polymethyl methacrylate (PMMA) and the like. Here, when the base plate110is required to have thermal resistance and chemical resistance, it is recommended that the base plate110should be formed of polycarbonate (PC).

The base plate110is able to diffuse the light as well as transmits the light. For example, the base plate110may be a diffuser plate or a light transmitting substrate including a diffusing agent. Here, the diffusing agent may include, for example, at least any one of SiO2, TiO2, ZnO, BaSO4, CaSO4, MgCO3, Al(OH)3, synthetic silica, glass beads and diamond. However the diffusing agent is not limited to this. The size of the diffusing agent's particle may be determined suitable for the diffusion of the light. For example, the particle may have a diameter of 5 μm to 7 μm.

The lens130may be disposed on one surface of the base plate110. Also, the lens130may project outwardly from the one surface of the base plate110. In other words, when the lens130is attached to the base plate110, the lens130may be disposed on the one surface of the base plate110. When the lens130and the base plate110are integrally formed with each other, the lens130may project outwardly from the one surface of the base plate110.

The lens130may have a hemispherical shape. However, the shape of the lens130is not limited to this. For example, the lens130may have various shapes such as a conical shape, a poly-pyramid shape, a cylindrical shape and a polygonal pillar shape and the like. In this specification, as shown inFIGS. 1 to 2, the hemispherical shape includes not only a geometrically perfect hemisphere but also a hemisphere having an irregular curvature.

The lens130may have an embossed shape. The lens130may also have an engraved shape as well.

The lens130may be formed of a plastic material. Specifically, the lens130may be formed of a resin. Here, the resin may be an UV resin which can be cured by ultraviolet (UV). The lens130may be any one of an acrylic resin, a silicone resin and a urethane resin as well as the UV resin.

The lens130may include at least one fluorescent material135.

The fluorescent material135may be uniformly distributed and disposed within the lens130.

The fluorescent material135is able to emit light excited by light incident from the outside.

The fluorescent material135may be at least any one of a silicate based material, a sulfide based material, a YAG based material, a TAG based material and a nitride based material. There is no limit to the kind of the fluorescent material.

The fluorescent material135may include at least one of yellow, red and green fluorescent materials which emit yellow, excited red and green lights. CaS:Eu which is a sulfide based inorganic fluorescent material is taken as an example of the red fluorescent material. SrS:Eu and MgS:Eu which are sulfide based inorganic fluorescent materials are taken as an example of the yellow fluorescent material. SrGa2S4:Eu and Eu2+ which are sulfide based inorganic fluorescent materials are taken as an example of the green fluorescent material.

The kind and amount of the fluorescent material135included in the lens130may be changed according to a light source. For example, when the light source is a white light source, the lens130may include the green and red fluorescent materials. When the light source is a blue light source, the lens130may include the green, yellow and red fluorescent materials.

The lens130may include at least one of a diffusing agent, an antifoaming agent, an additive and a curing agent.

The diffusing agent may scatter the light incident on the lens130. The diffusing agent may include at least any one of SiO2, TiO2, ZnO, BaSO4, CaSO4, MgCO3, Al(OH)3, synthetic silica, glass beads and diamond.

The antifoaming agent is able to remove the foams within the lens130and to obtain reliability of the phosphor plate100. The antifoaming agent may include, for example, octanol, cyclohexanol, ethylene glycol or various surfactants. However, the kind of the antifoaming agent is not limited to this.

The curing agent is able to stably cure the lens130.

The additive is able to uniformly the fluorescent material135within the lens130.

The phosphor plate100according to the first embodiment shown inFIGS. 1 to 2may be a phosphor micro lens array (PMLA). In the phosphor plate100according to the first embodiment, the hemisphere-shaped lenses130having the fluorescent material135are arranged on the base plate110in the form of an array. Therefore, the phosphor plate100has high excitation efficiency and makes it easy to diffuse and disperse the light.

FIG. 3is a perspective view of a phosphor plate according to a second embodiment.FIG. 4is a cross sectional view of the phosphor plate shown inFIG. 3taken along a line B-B′.

Referring toFIGS. 3 to 4, a phosphor plate100′ according to the second embodiment may be formed by adding a fluorescent layer150to the phosphor plate100according to the first embodiment shown inFIG. 1.

The fluorescent layer150may be disposed on the other surface of the base plate110.

The fluorescent layer150may include a resin. Further, the fluorescent layer150may include a silicone resin.

The fluorescent layer150may includes a fluorescent material155. For convenience of description, the fluorescent material135of the lens130is designated as a first fluorescent material. The fluorescent material155of the fluorescent layer150is a designated as a second fluorescent material.

The second fluorescent material155may be uniformly distributed and disposed within the fluorescent layer150.

The second fluorescent material155is able to emit light excited by light incident from the outside.

The second fluorescent material155may be the same as the first fluorescent material135. Besides, the second fluorescent material155may be different from the first fluorescent material135. For example, the first fluorescent material135may be a yellow fluorescent material and the second fluorescent material155may be a red fluorescent material. Here, when first fluorescent material135is a yellow fluorescent material and the second fluorescent material155is a red fluorescent material, the degree of dispersion of the fluorescent material can be enhanced. Specifically, when the yellow fluorescent material and the red fluorescent material are mixed with each other in any one of the lens130and the fluorescent layer150, the yellow fluorescent material and the red fluorescent material are not appropriately dispersed due to the specific gravity difference between the yellow fluorescent material and the red fluorescent material. However, the phosphor plate100′ according to the second embodiment includes the lens130and the fluorescent layer150both of which have the mutually different fluorescent materials. Accordingly, it is possible to enhance the degree of dispersion of the fluorescent material.

The first fluorescent material135may further include a green fluorescent material. When the first fluorescent material135further includes the green fluorescent material, optical characteristic, for example, a color rendering index and the like can be improved. Here, since the specific gravities of the yellow fluorescent material and the green fluorescent material are different from each other, the yellow fluorescent material and the green fluorescent material may not be well mixed with each other. For the purpose of overcoming such a problem, the lens130may consists of a first layer including the yellow fluorescent material and a second layer including the green fluorescent material.

Like the lens130, the fluorescent layer150may include at least one of a diffusing agent, an antifoaming agent, an additive and a curing agent.

Both when the plurality of the lenses130are disposed on the one surface of the base plate110and when the fluorescent layer150is disposed on the other surface of the base plate110, the phosphor plate100′ can be prevented from being curved. When the phosphor plate100according to the first embodiment is installed over a light source and used, stress is generated in the phosphor plate100by heat from the light source, and the phosphor plate100may be curved by the stress. However, since the phosphor plate100′ according to the second embodiment includes the lens which is disposed on the one surface of the base plate110and the fluorescent layer150which is disposed on the other surface of the base plate110, it is possible to prevent the phosphor plate100′ from being curved due to the heat from the light source.

The phosphor plate100′ according to the second embodiment shown inFIGS. 3 to 4may be a phosphor micro lens array (PMLA). In the phosphor plate100′ according to the second embodiment, the plurality of the lenses130having the first fluorescent material135are disposed on the one surface of the base plate110in the form of an array. The fluorescent layer150having the fluorescent material155is disposed on the other surface of the base plate110. Therefore, the phosphor plate100′ can be prevented from being curved due to the light source and the degree of dispersion of the fluorescent material is enhanced. Moreover, the phosphor plate100′ has the high excitation efficiency and improves luminous flux of light and a color rendering index. Also, uniformity characteristics of light can be enhanced.

FIG. 5is a perspective view of a phosphor plate according to a third embodiment.FIG. 6is a cross sectional view of the phosphor plate shown inFIG. 5taken along a line C-C′.

Referring toFIGS. 5 to 6, a phosphor plate100″ according to the third embodiment may be formed by adding a fluorescent layer170to the phosphor plate100′ according to the second embodiment shown inFIG. 3.

For convenience of description, the fluorescent layer170disposed on the one surface of the base plate110is designated as a first fluorescent layer170. The fluorescent layer150disposed on the other surface of the base plate110is designated as a second fluorescent layer150.

The first fluorescent layer170, together with the lens130, is disposed on the one surface of the base plate110. Specifically, the first fluorescent layer170is disposed on the one surface of the base plate110in such a manner that the lens130is not completely buried. From another point of view, the first fluorescent layer170may be disposed between the plurality of the lenses130.

The first fluorescent layer170, like the second fluorescent layer150, may include a resin. The first fluorescent layer170may include a silicone resin.

The first fluorescent layer170includes a fluorescent material175. For convenience of description, the fluorescent material175of the first fluorescent layer170is designated as a third fluorescent material.

The third fluorescent material175may be uniformly distributed and disposed within the first fluorescent layer170.

The third fluorescent material175is able to emit light excited by light incident from the outside.

The third fluorescent material175may be the same as the first and the second fluorescent materials135and155. Besides, the third fluorescent material175may be different from the first and the second fluorescent materials135and155. For example, the first fluorescent material135may be the yellow fluorescent material, the second fluorescent material155may be the red fluorescent material, and the third fluorescent material175may be the green fluorescent material. When the first fluorescent material135is the yellow fluorescent material, the second fluorescent material155is the red fluorescent material, and the third fluorescent material175is the green fluorescent material, the degree of dispersion of the fluorescent material can be enhanced. Specifically, when at least two of the yellow, red and green fluorescent materials are mixed with each other in any one of the lens130and the first and the second fluorescent layers170and150, the fluorescent materials are not well dispersed due to the specific gravity difference among the yellow, red and green fluorescent materials. However, the phosphor plate100″ according to the third embodiment includes the lens130and the first and the second fluorescent layers170and150, all of which have the mutually different fluorescent materials. Accordingly, it is possible to enhance the degree of dispersion of the fluorescent material. Also, when the first to the third fluorescent materials135,155and175are different from each other, the phosphor plate100″ has high excitation efficiency.

Like the lens130or the first fluorescent layer170, the second fluorescent layer150may include at least one of a diffusing agent, an antifoaming agent, an additive and a curing agent.

Both when the plurality of the lenses130and the first fluorescent layer170are disposed on the one surface of the base plate110and when the second fluorescent layer150is disposed on the other surface of the base plate110, the phosphor plate100″ can be prevented from being curved due to a light source.

The phosphor plate100″ according to the third embodiment shown inFIGS. 5 to 6may be a phosphor micro lens array (PMLA). In the phosphor plate100″ according to the third embodiment, the lens130includes the first fluorescent material135, has a hemispherical shape and is disposed on the base plate110in the form of an array. The second fluorescent layer150including the second fluorescent material155is disposed on the other surface of the base plate110. The first fluorescent layer170including the third fluorescent material175is disposed together with the lens130on the one surface of the base plate110. Therefore, the phosphor plate100″ can be prevented from being curved due to the light source and the degree of dispersion of the fluorescent material is enhanced. Moreover, the phosphor plate100″ has the high excitation efficiency and improves luminous flux of light and a color rendering index. Also, uniformity characteristics of light can be enhanced.

FIG. 7is a perspective view of a phosphor plate according to a fourth embodiment.FIG. 8is a cross sectional view of the phosphor plate shown inFIG. 7taken along a line D-D′.

Referring toFIGS. 7 to 8, a phosphor plate100′″ according to the fourth embodiment may be formed by adding a lens160to the phosphor plate100according to the first embodiment shown inFIG. 1. For convenience of description, the lens130disposed on the one surface of the base plate110is designated as a first lens. The lens160disposed on the other surface of the base plate110is designated as a second lens.

The second lens160may be disposed on the other surface of the base plate110or may project outwardly from the other surface of the base plate110.

The first lens130may be disposed corresponding to the second lens160with respect to the base plate110. However, the first and the second lenses130and160may be disposed without being limited to this. In other words, the first and the second lenses130and160may be disposed not to correspond to each other, that is, may be disposed out of line with each other.

Like the first lens130, the second lens160may have a hemispherical shape. However, the shape of the lens160is not limited to this. The second lens160may have various shapes such as a conical shape, a poly-pyramid shape, a cylindrical shape and a polygonal pillar shape and the like.

The second lens160may have an embossed shape. The second lens160may also have an engraved shape as well.

The shape of the second lens160may be the same as or different from the shape of the first lens130.

The second lens160may be formed of a plastic material. Particularly, the second lens160may be formed of a resin among the plastic materials. The resin may be also an UV resin which can be cured by ultraviolet. The second lens160may be any one of an acrylic resin, a silicone resin and a urethane resin as well as the UV resin.

The second lens160may include a fluorescent material165. For convenience of description, the fluorescent material135included in the first lens130is designated as a first fluorescent material. The fluorescent material165included in the second lens160is designated as a second fluorescent material.

The second fluorescent material165may be uniformly distributed and disposed within the second lens160.

The second fluorescent material165is able to emit light excited by light incident from the outside.

The second fluorescent material165may be the same as the first fluorescent material135. Besides, the second fluorescent material165may be different from the first fluorescent material135. For example, the first fluorescent material135may be the yellow fluorescent material and the second fluorescent material165may be the red fluorescent material. When first fluorescent material135is the yellow fluorescent material and the second fluorescent material165is the red fluorescent material, the degree of dispersion of the fluorescent material can be enhanced. Specifically, when at least two of the yellow, red and green fluorescent materials are mixed with each other in any one of the first lens130and the second lens160, the fluorescent materials are not well dispersed due to the specific gravity difference among the yellow, red and green fluorescent materials. However, the phosphor plate100′″ according to the fourth embodiment includes the first lens130and the second lens160, both of which have the mutually different fluorescent materials. Accordingly, it is possible to enhance the degree of dispersion of the fluorescent material. Also, when the first to the second fluorescent materials135and165are different from each other, the phosphor plate100′″ has high excitation efficiency.

The first fluorescent material135or the second fluorescent material165may further include a green fluorescent material. When the first fluorescent material135or the second fluorescent material165further includes the green fluorescent material, optical characteristic, for example, a color rendering index and the like can be improved. In this case, since the specific gravities of the first and the second fluorescent materials135and165included in the first and the second lenses130and160are different from the specific gravity of the green fluorescent material, the fluorescent materials may not be well mixed with each other. For the purpose of overcoming such a problem, a description will be provided with reference toFIG. 9.

FIG. 9is a cross sectional view showing a modified example of the phosphor plate shown inFIG. 8.

Referring toFIG. 9, the first lens130may consist of a first layer130aincluding the first fluorescent material135and a second layer130bincluding the green fluorescent material.

The second lens160may consist of a first layer160aincluding the second fluorescent material165and a second layer160bincluding the green fluorescent material.

Referring to againFIGS. 7 to 8, like the first lens130, the second lens160may include at least one of a diffusing agent, an antifoaming agent, an additive and a curing agent.

Both when the first lens130is disposed on the one surface of the base plate110and when the second lens160is disposed on the other surface of the base plate110, the phosphor plate100′″ can be prevented from being curved.

The phosphor plate100′″ according to the fourth embodiment shown inFIGS. 7 to 8may be a phosphor micro lens array (PMLA). In the phosphor plate100′″ according to the fourth embodiment, the first lens130having the first fluorescent material135is disposed on the one surface of the base plate110, and the second lens160having the second fluorescent material165is disposed on the other surface of the base plate110. Therefore, the phosphor plate100′″ can be prevented from being curved due to the light source and the degree of dispersion of the fluorescent material is enhanced. Moreover, the phosphor plate100′″ has the high excitation efficiency and improves luminous flux of light and a color rendering index. Also, uniformity characteristics of light can be enhanced.

FIG. 10is a perspective view of a phosphor plate according to a fifth embodiment.FIG. 11is a cross sectional view of the phosphor plate shown inFIG. 10taken along a line E-E′.

Referring toFIGS. 10 to 11, a phosphor plate100″″ according to the fifth embodiment may be formed adding a first fluorescent layer170and a second fluorescent layer190to the phosphor plate100′″ according to the fourth embodiment shown inFIGS. 7 to 8.

The first fluorescent layer170, together with the first lens130, may be disposed on the one surface of the base plate110. The second fluorescent layer190, together with the second lens160, may be disposed on the other surface of the base plate110.

The first fluorescent layer170may be disposed to bury a portion of the first lens130. The second fluorescent layer190may be disposed to bury a portion of the second lens160.

The first fluorescent layer170may be disposed between the first lenses130. The second fluorescent layer190may be disposed between the second lenses160.

The first and the second fluorescent layers170and190may include a resin.

The first and the second fluorescent layers170and190include fluorescent materials175and195respectively. For convenience of description, the fluorescent material175included in the first fluorescent layer170is designated as a third fluorescent material. The fluorescent material195included in the second fluorescent layer190is designated as a fourth fluorescent material.

The third fluorescent material175may be uniformly distributed and disposed within the first fluorescent layer170. The fourth fluorescent material195may be uniformly distributed and disposed within the second fluorescent layer190.

The third and the fourth fluorescent materials175and195are able to emit light excited by light incident from the outside.

The third and the fourth fluorescent materials175and195may be the same as the first and the second fluorescent materials135and165. Besides, the third and the fourth fluorescent materials175and195may be different from the first and the second fluorescent materials135and165. For example, the third and the fourth fluorescent materials175and195may be the green fluorescent material. That is, the first fluorescent material135may be the yellow fluorescent material, the second fluorescent material165may be the red fluorescent material, and the third and the fourth fluorescent materials175and195may be the green fluorescent material. In this case, if the light source emits blue light, excitation efficiency can be improved. Also, the degree of dispersion of the fluorescent material can be enhanced.

Like the first and the second lenses130and160, the first and second fluorescent layers170and190may include at least one of a diffusing agent, an antifoaming agent, an additive and a curing agent.

In the phosphor plate100″″ according to the fifth embodiment shown inFIGS. 10 to 11, the first lens130and the first fluorescent layer170are disposed on the one surface of the base plate110, and the second lens160and the second fluorescent layer190are disposed on the other surface of the base plate110. Therefore, the phosphor plate100″″ can be prevented from being curved due to the heat from the light source and the degree of dispersion of the fluorescent material is enhanced. Moreover, the phosphor plate100″″ has the high excitation efficiency and improves luminous flux of light and a color rendering index. Also, uniformity characteristics of light can be enhanced.

FIGS. 12 to 15are views for describing a method for manufacturing the phosphor plate according to the first embodiment shown inFIGS. 1 to 2.

Referring toFIG. 12, a master mold having predetermined holes shown inFIG. 12is provided. Here, the shape of the lens130depends on the shape of the hole.

The base plate110is provided and a lens layer130is formed on the base plate110. Here, a lens layer130may include the fluorescent material135shown inFIG. 2. That is, the lens layer130may be formed by mixing a resin and the fluorescent material135and may be disposed on the base plate110in a liquid state.

Referring toFIG. 13, the base plate110is moved in the direction of the master mold such that the lens layer130comes in direct contact with the master mold, and then a predetermined pressure is applied such that the master mold and the base plate110are pressed to each other. Accordingly, as shown inFIG. 14, the liquefied lens layer130is inserted into the holes of the master mold.

As shown inFIG. 14, the lens layer130is sufficiently cured by irradiating UV from an opposite side to the side on which the lens130is formed. The lens130can be formed by curing the lens layer130.

As shown inFIG. 15, the base plate110and the lens130are released from the master mold.

Through the manufacturing process shown inFIGS. 12 to 15, the phosphor plate100according to the first embodiment can be manufactured. Additionally, the phosphor plates100′,100″,100′″ and100″″ according to the second to the fifth embodiments shown inFIGS. 3 to 11can be manufactured through the manufacturing process shown inFIGS. 12 to 15.

FIG. 16is a perspective view of a lighting device according to the embodiment.FIG. 17is a perspective view of the lighting device without the phosphor shown inFIG. 16.

Referring toFIGS. 16 to 17, the lighting device according to the embodiment may include a phosphor plate1000, a case2000and a light emitting module3000.

The phosphor plate1000may be the phosphor plate100ac cording to the first embodiment shown inFIGS. 1 to 2or may be any one among the phosphor plates100′,100″,100′″ and100″″ according to the second to the fifth embodiments shown inFIGS. 3 to 11.

The phosphor plate1000may be disposed over the light emitting module3000, receive light emitted from the light emitting module3000and emit light excited by the received light.

The case2000is able to receive the phosphor plate1000and the light emitting module3000. Specifically, the light emitting module3000may be disposed on the bottom surface of the recess of the case2000. The phosphor plate1000may be disposed to cover the recess.

The case2000may receive heat generated from the light emitting module3000and radiate the heat. That is, the case2000can function as a heat sink. Therefore, the case2000may be formed of aluminum and an alloy including aluminum which have high thermal conductivity and excellent heat radiation efficiency.

The light emitting module3000may be disposed on the bottom surface of the recess of the case2000. The light emitting module3000may include a light emitting device like a light emitting diode and a substrate on which a plurality of the light emitting devices are arranged.

The light emitting module3000may be disposed separately from the phosphor plate1000at a predetermined interval by the case2000.

The lateral surface of the recess of the case2000may be a reflective surface capable of reflecting the light from the light emitting module3000. Therefore, the lateral surface of the recess of the case2000is able to reflect the light emitted from the light emitting module3000to the phosphor plate1000.

A wire4000passes through the case2000and is electrically connected to the light emitting module3000. The wire4000is able to supply electric power to the light emitting module3000from an external power supply.