Household appliance with display function

Abstract

Provided is a household appliance (100) comprising a light source assembly (102) for generating light (L1) having a first spectral composition, and a housing (104) containing components of the household appliance. The components housed within the housing include the light source assembly. The housing comprises a luminescent element (106) excitable by the light generated by the light source assembly to emit light (L2) having a second spectral composition that is different from the first spectral composition. At least one optically opaque element (108, 110) is arranged between the light source assembly and the luminescent element, with at least one light-transmitting portion (112, 114) being defined in the optically opaque element to allow light generated by the light source assembly to pass through the optically opaque element to reach the luminescent element. A defined arrangement of the at least one light-transmitting portion determines a shape of the light emanating from the luminescent element and the housing that visually conveys information to a user of the household appliance.

Description

FIELD OF THE INVENTION

[0001] The invention relates to a household appliance, such as an air treatment device, having a display that visually conveys information to a user of the household appliance.BACKGROUND OF THE INVENTION

[0002] Displays are widely used in household appliances to provide information to the user, e.g. concerning the operational state of the appliance. In the case of, for instance, an air purifier, the air purifier's display may indicate an operational mode, e.g. fan setting, an indication of the status of certain components included in the air purifier, such as its particle or gas filters etc., and / or other relevant information, e.g. temperature, humidity, and the like.

[0003] Such information can be displayed in different forms, such as using numbers, letters or symbols.

[0004] While it is thus desirable to incorporate display functionality into such household appliances, inclusion of a display can risk cluttering the exterior of the household appliance, and a blank display not showing any information (when none is required to be shown) can risk that the user misinterprets the blank display as meaning the household appliance is faulty. Alternatively or additionally, the display may not visually convey information to the user with sufficient clarity and emphasis.SUMMARY OF THE INVENTION

[0005] The invention is defined by the claims.

[0006] According to examples in accordance with an aspect of the invention, there is provided a household appliance comprising: a light source assembly for generating light having a first spectral composition; a housing containing components of the household appliance, said components including the light source assembly, the housing comprising a luminescent element excitable by the light generated by the light source assembly to emit light having a second spectral composition that is different from the first spectral composition; and at least one optically opaque element arranged between the light source assembly and the luminescent element, at least one light-transmitting portion being defined in the optically opaque element to allow light generated by the light source assembly to pass through the optically opaque element(s) to reach the luminescent element, wherein a defined arrangement of the at least one light-transmitting portion determines a shape of the light emanating from the luminescent element and the housing.

[0007] The shape of the light emanating from the luminescent element and the housing can visually convey information to a user of the household appliance.

[0008] It is noted that the light source assembly, the optically opaque element in which the light-transmitting portion(s) is / are defined, and the luminescent element can be regarded as being included in a display assembly of the household appliance.

[0009] The luminescent element can help to provide a vivid illumination when the luminescent element is receiving the light generated by the light source assembly, particularly when the household appliance is situated in a relatively dark environment.

[0010] The luminescent element can enable various different colors of light to emanate therefrom and thus emanate from the housing of the household appliance. Alternatively or additionally, the color of the light emitted by the luminescent element can be deeper compared to that emitted by, for example, a household device which differs from the one being described only in that no luminescent element is included.

[0011] In some embodiments, the housing comprises a non-luminescent housing portion arranged adjacent to, e.g. at least partially surrounding, the luminescent element, and a color difference, ΔE 00 , as measured using ASTM D2244-23, between the non-luminescent housing portion and at least part of the luminescent element, when the at least part of the luminescent element is not being excited by the light generated by the light source assembly, is 15 or less.

[0012] By the color difference being 15 or less between the non-luminescent housing portion and the at least part of, e.g. an opaque region of, the adjacent luminescent element, the at least part of the luminescent element can be less noticeable, in other words hidden, when not being excited by the light from the light source assembly to emit light.

[0013] Thus, the household appliance can have display functionality which is hidden when not being used, in other words when the luminescent element is not receiving light from the light source assembly, e.g. due to the light source assembly being switched off. Such hiding of the luminescent element by matching its color with the adjacent non-luminescent housing portion can also assist to make the visual change more perceptible when the luminescent element is excited by the light from the light source assembly to emit light.

[0014] In some embodiments, the color difference, ΔE 00 , as measured using ASTM D2244-23, is 5 or less, preferably 4 or less. By the color difference being 5 or less, preferably 4 or less, the at least part of the luminescent element may be even less noticeable when the luminescent element is not being excited by the light from the light source assembly to emit light.

[0015] It is noted that the color difference can be measured using a handheld spectrophotometer, such as the spectro2guide Color Control Handheld Spectrophotometer from BYK, by holding the sensing part of the spectrophotometer against the non-luminescent housing portion, and holding the sensing part against the luminescent element, while the luminescent element is not receiving light from the light source assembly.

[0016] The luminescent element can have any suitable composition provided that the luminescent element is capable of being excited by the light emitted by the light source assembly (having the first spectral composition) and emitting the light having the second spectral composition that is different from the first spectral composition.

[0017] The luminescent element can include one or more phosphors that is / are excitable by the light from the light source assembly to emit the light having the second, different, spectral composition.

[0018] Alternatively or additionally, the luminescent element can comprise at least one inorganic luminescent material, for example at least one inorganic luminescent material comprising an inorganic fluorescent material. Inorganic luminescent materials may benefit from being relatively resistant to change over time as a consequence of repeated exposure to light (in other words may have relatively good lightfastness), heat etc.

[0019] The luminescent material(s) can be arranged in, e.g. to form, the luminescent element in any suitable manner. In some embodiments, the luminescent element comprises one or more luminescent materials mixed with and / or coated onto a polymer. For example, the luminescent material(s) can be mixed with a resin or incorporated into a thermoplastic. This may provide a readily manufacturable way of providing the luminescent element.

[0020] In some embodiments, the luminescent element comprises a plurality of different luminescent materials, e.g. a plurality of different phosphors. In such embodiments, each of the plurality of different luminescent materials can be excited by the light generated by the light source assembly to emit light having a different spectral composition from light emitted by the other luminescent material(s) when excited by the light generated by the light source assembly.

[0021] Thus, different luminescent materials can be used to tune the spectral composition of the light emanating from the luminescent element. Alternatively or additionally, the different luminescent materials can be used to adjust the color of the luminescent element when the luminescent element is not being excited by the light from the light source assembly, for example to help with color-matching with the non-luminescent housing portion adjacent to the luminescent element.

[0022] In some embodiments, the luminescent element is configured to allow a fraction of the light from the light source assembly to pass therethrough without exciting the luminescent element. In such embodiments, light emanating from the luminescent element can comprise the first spectral composition combined with the second spectral composition. Thus, the spectral composition of the light emanating from the luminescent element can be tuned via mixing the fraction of light from the light source assembly with the light emitted by the excited luminescent element.

[0023] For instance, the light source assembly is configured to generate light centered at around 450 nm and the luminescent element is selected to absorb light at that wavelength and re-emit light at around 570 nm.

[0024] In this non-limiting example, part of the original about 450 nm (blue) light from the light source assembly and the about 570 nm (yellow) light from the luminescent element, e.g. fluorophore thereof, can now simultaneously leave the luminescent element, resulting in a white or off-white appearance of the light emanating from the luminescent element.

[0025] In some embodiments, the luminescent element comprises different regions having different luminescent properties relative to each other. For example, the region of the luminescent element aligned with the light-transmitting portion(s) can have different luminescent properties relative to region(s) of the luminescent element that is / are not aligned with the light-transmitting portion(s).

[0026] The luminescent properties can be made different in the different regions in any suitable manner, for example by using a different concentration of luminescent material and / or a different thickness of the luminescent element in the respective regions.

[0027] In embodiments in which the color difference is 15 or less, e.g. 5 or less, preferably 4 or less, between the non-luminescent housing portion and the at least part of the adjacent luminescent element, this maximum color difference may apply in respect of at least one of the regions, e.g. an opaque region, of the luminescent element.

[0028] More generally, the luminescent element may include at least one fluorescent material that is caused to fluoresce by the light generated by the light source assembly. For example, the luminescent material(s) of the luminescent element comprise a fluorophore, e.g. an inorganic, for instance garnet-based, fluorophore.

[0029] A non-limiting example of a garnet-based fluorophore is YAG:Ce (Y 3 Al 5 O 12 :Ce), which absorbs light whose wavelength is about 450 nm, and re-emits light whose wavelength is about 570 nm.

[0030] More generally, examples of luminescent materials which may be included in the luminescent element include garnet-based YAG:Ce (Y 3 Al 5 O 12 :Ce) materials, lorthosilicates, nitrides, oxinitrides, uAG, phosphates, luminescent quantum dots and / or nanocrystals such as CuInS 2 , ZnSe, CdSe, ZnS, InP, PbSe, and PbS.

[0031] In some embodiments, the defined arrangement of the at least one light-transmitting portion comprises symbol-defining portion(s), with the symbol-defining portion(s) determining symbol shape(s) of the light emanating from the luminescent element. Such symbol shape(s) can visually convey information to the user of the household appliance when the symbol-defining portion(s) is / are transmitting light from the light source assembly to cause the symbol shaped-light to emanate from the luminescent element.

[0032] As an alternative or in addition to the symbol-defining portion(s), the defined arrangement of the at least one light-transmitting portion can comprise alphanumeric character-defining portions, with the alphanumeric character-defining portions determining alphanumeric character shapes of the light emitted by the luminescent element.

[0033] Such alphanumeric character shape(s) can visually convey numerical and / or textual information to a user of the household appliance when the alphanumeric character-defining portion(s) is / are transmitting light from the light source assembly to cause the alphanumeric character-shaped light to emanate from the luminescent element.

[0034] In some embodiments, the alphanumeric character-defining portions comprise numeral-defining portions, with the numeral-defining portions determining numeral shapes of the light emanating from the luminescent element.

[0035] The light-transmitting portion(s) can be realized in any suitable manner. In some embodiments, the optically opaque element includes an optically opaque layer in which light-transmitting region(s) is / are defined.

[0036] Defining the light-transmitting region(s) in the optically opaque layer can, for example, be implemented via selective removal of the region(s) of the optically opaque layer. Such selective removal can, for instance, be achieved using an etching process.

[0037] In some embodiments, light-transmitting portion(s) defined in the optically opaque element is / are configured so that only the wavelength(s) of light corresponding to the emission of the light source assembly is / are transmitted therethrough, while all other wavelengths are absorbed.

[0038] This may help to achieve a more homogenous appearance throughout the surface of the luminescent element, particularly when an "off state" is adopted in which the luminescent element is not receiving light from the light source assembly.

[0039] As an alternative or in addition to the optically opaque layer, the optically opaque element can include an intermediate member arranged between the light source assembly and the luminescent element, with at least one light channel being defined in the intermediate member. In such embodiments, the at least one light channel can channel light from the light source assembly to the luminescent element. Such light channel(s) can provide a convenient way of controlling incidence of light from the light source assembly on the luminescent element, particularly in embodiments in which it is desired for the light emanating from the luminescent element to be in the shape of numerals.

[0040] In embodiments in which the at least one light channel comprises a plurality of light channels, the plurality of light channels can include one or more sets of numeral-defining light channels, with each set of numeral-defining light channels comprising seven light channels.

[0041] In such embodiments, the seven light channels can be arranged so that illuminating two or more of the seven light channels permits each of the numerals 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 to be presented.

[0042] In such embodiments, the light source assembly can, for example, include a light source, e.g. a light source in the form of a light emitting diode, for illuminating one of the numeral-defining portions, so that seven light sources are provided for each set.

[0043] In some embodiments, the, e.g. each of the, at least one light channel is at least partially delimited by an optically reflective surface. Such an optically reflective surface can assist to ensure optically efficient transmission of light from the light source assembly to the luminescent element via the light channel(s).

[0044] The optically reflective surface can be implemented in any suitable manner, for example by a white pigment coating the wall surrounding the respective light channel and / or by the optically reflective surface comprising an aluminum-based reflective material.

[0045] The light source(s) included in the light source assembly can be of any suitable type. Particular mention is made of light emitting diode(s), LED(s), being included in the light source assembly, since LED(s) can be selected to emit light having a wavelength that excites luminescent material(s) included in the luminescent element.

[0046] In general terms, the spectral composition of the light generated by the light source assembly can be chosen such that it corresponds to absorption peak(s) of the luminescent material(s) included in the luminescent element. Preferably, blue light-emitting LED(s) is / are included in the light source assembly.

[0047] In some embodiments, the household appliance is an air treatment device, for example an air treatment device comprising an air purifier. In such embodiments, the components housed within the housing can include an air displacement assembly, e.g. fan unit, and / or air purification element(s), such as filter(s), for purifying air.

[0048] The principles of the present disclosure may be beneficial when applied in household appliances in general, but especially in air treatment devices, such as air purifiers, air dehumidifiers, air humidifiers or comfort fans, in which sleek display functionality is desired by consumers.

[0049] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.BRIEF DESCRIPTION OF THE DRAWINGS

[0050] For a better understanding of the invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which: FIG. 1 schematically depicts part of a household appliance according to an example; FIG. 2 shows symbol shapes and alphanumeric shapes of light emanating from a luminescent element included in such a household appliance; FIG. 3 shows part of a household appliance according to another example; FIG. 4A depicts light emanating from a household appliance's luminescent element when the luminescent element is excited by light from a light source assembly included in the household appliance; FIG. 4B depicts the luminescent element not being excited by the light from the light source assembly in the household appliance; FIGs. 5 to 8 schematically depict various examples of the household appliance's luminescent element and adjacent non-luminescent housing portion; and FIG. 9 schematically depicts part of a household appliance according to a further example. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0051] The invention will be described with reference to the Figures.

[0052] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the apparatus, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, systems and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawings. It should be understood that the Figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts.

[0053] Provided is a household appliance comprising a light source assembly for generating light having a first spectral composition, and a housing containing components of the household appliance. The components housed within the housing include the light source assembly. The housing comprises a luminescent element excitable by the light generated by the light source assembly to emit light having a second spectral composition that is different from the first spectral composition. At least one optically opaque element is arranged between the light source assembly and the luminescent element, with at least one light-transmitting portion being defined in the optically opaque element to allow light generated by the light source assembly to pass through the optically opaque element to reach the luminescent element. A defined arrangement of the at least one light-transmitting portion determines a shape of the light emanating from the luminescent element and the housing that visually conveys information to a user of the household appliance.

[0054] FIG. 1 provides a schematic cross-sectional view of part of a household appliance 100 according to an example. The household appliance 100 comprises a light source assembly 102 that is housed within the household appliance's 100 housing 104.

[0055] It is noted that the housing 104 can house components (not visible in FIG. 1) other than the light source assembly 102.

[0056] The household appliance 100 can be of any suitable type. In some embodiments, the household appliance 100 is an air treatment device, for example an air treatment device comprising an air purifier. In such embodiments, the components housed within the housing 104 can include an air displacement assembly, e.g. fan unit, and / or air purification element(s), such as filter(s), for purifying air.

[0057] More generally, the light source assembly 102 is configured to generate light L1 having a first spectral composition, and the housing 104 comprises a luminescent element 106 excitable by the light L1 generated by the light source assembly 102 to emit light L2 having a second spectral composition that is different from the first spectral composition. The luminescent element 106 can help to provide a vivid illumination when the luminescent element 106 is receiving the light L1 generated by the light source assembly 102, particularly when the household appliance 100 is situated in a relatively dark environment.

[0058] The color of the light L2 emitted by the luminescent element 106 can be deeper compared to that emitted from, for example, a household device which differs from the one being described only in that no luminescent element 106 is included. Moreover, and as explained in more detail herein below, the luminescent element 106 can enable various different colors of light L2 to emanate therefrom and thus emanate from the housing 104 of the household appliance 100.

[0059] As shown in FIG. 1, at least one optically opaque element 108, 110 is arranged between the light source assembly 102 and the luminescent element 106, with at least one light-transmitting portion 112, 114 being defined in the optically opaque element(s) 108, 110 to allow the light L1 generated by the light source assembly 102 to pass through the optically opaque element(s) 108, 110 to reach the luminescent element 106.

[0060] A defined arrangement of the at least one light-transmitting portion 112, 114 determines a shape of the light L2 emanating from the luminescent element 106 and the housing 104. The shape of the light L2 emanating from the luminescent element 106 and the housing 104 can visually convey information to a user of the household appliance 100.

[0061] The purpose of the optically opaque element 108, 110 is to prevent the light L1 from hitting the luminescent element 106 at all positions but those where the shape(s) to be displayed is / are located.

[0062] The light-transmitting portion(s) 112, 114 can be realized in any suitable manner. In some embodiments, such as shown in FIG. 1, the optically opaque element 110, 112 includes an optically opaque layer 110 in which light-transmitting region(s) 114 is / are defined.

[0063] Defining the light-transmitting region(s) 114 in the optically opaque layer 110 can, for example, be implemented via selective removal of the region(s) of the optically opaque layer 110. Such selective removal can, for instance, be achieved using an etching process.

[0064] The optically opaque layer 110 can be formed in any suitable manner. The optically opaque layer 110 may, for instance, comprise a mylar film, a layer of ink, e.g. a layer of ink printed on a surface of the luminescent element 106 that faces the light source assembly 102.

[0065] In some embodiments, light-transmitting portion(s) 112, 114 defined in the optically opaque element 108, 110 may be configured so that only the wavelength(s) of light corresponding to the emission of the light source assembly 102 is / are transmitted therethrough, while all other wavelengths are absorbed.

[0066] This may help to achieve a more homogenous appearance throughout the surface of the luminescent element 106, particularly when an "off state" is adopted in which the luminescent element 106 is not receiving light L1 from the light source assembly 102.

[0067] This can be achieved by, for example, the optically opaque layer 110 including pigment(s) in the light-transmitting region(s) 114 thereof whose absorption properties mean that only the wavelength(s) of light corresponding to the emission of the light source assembly 102 is / are transmitted therethrough.

[0068] As an alternative or in addition to the optically opaque layer 110, the optically opaque element 108, 110 can include an intermediate member 108 arranged between the light source assembly 102 and the luminescent element 106, with at least one light channel 112 being defined in the intermediate member 108. In such embodiments, the at least one light channel 112 can channel light L1 from the light source assembly 102 to the luminescent element 106. Such light channel(s) 112 can provide a convenient way of controlling incidence of light L1 from the light source assembly 102 on the luminescent element 106, particularly in embodiments in which it is desired for the light emanating from the luminescent element 106 to be in the shape of numerals, as explained in more detail herein below.

[0069] It is noted that in embodiments in which the optically opaque element 108, 110 includes the intermediate member 108 and the optically opaque layer 110, the light channel(s) 112 can be arranged to channel the light L1 from the light source assembly 102 to the light-transmitting region(s) 114 defined in the optically opaque layer 110.

[0070] In some embodiments, and still referring to FIG. 1, the, e.g. each of the, at least one light channel 112 is at least partially delimited by an optically reflective surface 113. Such an optically reflective surface 113 can assist to ensure optically efficient transmission of light L1 from the light source assembly 102 to the luminescent element 106 via the light channel(s) 112.

[0071] The optically reflective surface 113 can be implemented in any suitable manner, for example by a white pigment coating the wall surrounding the respective light channel 112 and / or by the optically reflective surface 113 comprising an aluminum-based reflective material.

[0072] In some embodiments, and referring to the upper part of FIG. 2, the defined arrangement of the at least one light-transmitting portion 112, 114 comprises symbol-defining portion(s), with the symbol-defining portion(s) determining symbol shape(s) 114A of the light emanating from the luminescent element 106. Such symbol shape(s) 114A can visually convey information to a user of the household appliance 100 when the symbol-defining portion(s) is / are transmitting light L1 from the light source assembly 102 to cause the symbol shaped-light to emanate from the luminescent element 106.

[0073] In the non-limiting example provided at the top left part of FIG. 2, the symbol-defining portion(s) determine a symbol shape 114A in the form of a capital letter "A" with two vertical lines on each side of the "A". This can, for example, denote an operational mode of the household appliance 100.

[0074] In the non-limiting example provided at the top right part of FIG. 2, the symbol-defining portion(s) determine a symbol shape 114A in the form of a locked padlock. The latter can, for instance, indicate a locked mode of the household appliance 100, e.g. a locked mode of a user input interface included in the household appliance 100.

[0075] As an alternative or in addition to the symbol-defining portion(s), the defined arrangement of the at least one light-transmitting portion 112, 114 can comprise alphanumeric character-defining portions, with the alphanumeric character-defining portions determining alphanumeric character shapes 114B of the light emanating from the luminescent element 106, as shown in the bottom part of FIG. 2.

[0076] Such alphanumeric character shape(s) 114B can visually convey numerical and / or textual information to a user of the household appliance 100 when the alphanumeric character-defining portion(s) is / are transmitting light L1 from the light source assembly 102 to cause the alphanumeric character-shaped light to emanate from the luminescent element 106.

[0077] In some embodiments, the alphanumeric character-defining portions comprise numeral-defining portions, with the numeral-defining portions determining numeral shapes of the light emanating from the luminescent element 106.

[0078] In embodiments in which the at least one light channel 112 comprises a plurality of light channels 112, such as shown in FIG. 3, the plurality of light channels 112 can include one or more sets of numeral-defining light channels 112, with each set of numeral-defining light channels comprising seven light channels 112.

[0079] In such embodiments, the seven light channels 112 can be arranged so that illuminating two or more of the seven light channels 112 permits each of the numerals 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 to be presented.

[0080] In such embodiments, the light source assembly 102 can, for example, include a light source 115, e.g. a light source 115 in the form of a light emitting diode, for illuminating one of the numeral-defining portions, so that seven light sources 115 are provided for each set.

[0081] It is noted more generally that the light source(s) 115 included in the light source assembly 102 can be of any suitable type. Particular mention is made of light emitting diode(s), LED(s), being included in the light source assembly 102, since LED(s) can be selected to emit light L1 having a wavelength that excites luminescent material(s) included in the luminescent element 106.

[0082] In general terms, the spectral composition of the light L1 generated by the light source assembly 102 can be chosen such that it corresponds to absorption peak(s) of the luminescent material(s) included in the luminescent element 106. Preferably, blue light-emitting LED(s) is / are included in the light source assembly 102.

[0083] In some embodiments, and referring again to FIG. 1, the housing 104 comprises a non-luminescent housing portion 116 arranged adjacent to, e.g. surrounding, the luminescent element 106, and a color difference, ΔE 00 , as measured using ASTM D2244-23, between the non-luminescent housing portion 116 and at least part of the luminescent element 106, when the luminescent element 106 is not being excited by the light L1 generated by the light source assembly 102, is 15 or less.

[0084] By the color difference being 15 or less between the non-luminescent housing portion 116 and the at least part of, e.g. the entirety of, the adjacent luminescent element 106, the luminescent element 106 can be less noticeable, in other words hidden, when not being excited by the light L1 from the light source assembly 102 to emit light.

[0085] Thus, the household appliance 100 can have display functionality which is hidden when not being used, in other words when the luminescent element 106 is not receiving light L1 from the light source assembly 102, e.g. due to the light source assembly 102 being switched off. Such hiding of the luminescent element 106 by matching its color with the adjacent non-luminescent housing portion 116 can also assist to make the visual change more perceptible when the luminescent element 106 is excited by the light L1 from the light source assembly 102 to emit light L2.

[0086] A non-limiting illustrative example of this is schematically shown in FIGs. 4A and 4B. In FIG. 4A, the luminescent element 106 is being excited by the light source assembly 102 to emit light L2, in this case in the form of numeral shapes 114B, and the color of the light emanating from the luminescent element 106 contrasts with the color of the non-luminescent housing portion 116. However, in FIG. 4B, the luminescent element 106 is no longer receiving light L1 from the light source assembly 102, e.g. due to the light source assembly 102 being switched off, and the minimal color difference between the non-emitting luminescent element 106 and the adjacent non-luminescent housing portion 116 hides the display functionality.

[0087] For instance, a luminescent material included in the luminescent element 106 may be a garnet-based YAG:Ce (Y 3 Al 5 O 12 :Ce) material. In this non-limiting example, under normal ambient light (without the light L1 generated by the light source assembly 102), the luminescent element 106 appears yellowish / orange, which matches the color of the non-luminescent housing portion 116.

[0088] In some embodiments, the color difference, ΔE 00 , as measured using ASTM D2244-23, is 5 or less, preferably 4 or less. By the color difference being 5 or less, preferably 4 or less, the luminescent element 106 may be even less noticeable when the luminescent element 106 is not being excited by the light L1 from the light source assembly 102 to emit light L2.

[0089] The manner in which this color matching is achieved is not particularly limited. In some embodiments, and referring to FIGs. 5 to 8, pigment(s) 117, and amount(s) of the pigment(s) 117, included in the non-luminescent housing portion 116, and luminescent material(s) 107; 107A, 107B, 107C, and amounts of the luminescent material(s) 107; 107A, 107B, 107C included in the luminescent element 106 can be selected to achieve the color difference of 15 or less, preferably 5 or less, and most preferably 4 or less. The latter can be directly and positively verified using the method set out in ASTM D2244-23.

[0090] It is noted that the color difference can be measured using a handheld spectrophotometer, such as the spectro2guide Color Control Handheld Spectrophotometer from BYK, by holding the sensing part of the spectrophotometer against the non-luminescent housing portion 116, and holding the sensing part against the luminescent element 106, while the luminescent element 106 is not receiving light from the light source assembly 102.

[0091] More generally, the luminescent element 106 can have any suitable composition provided that the luminescent element 106 is capable of being excited by the light L1 emitted by the light source assembly 102 (having the first spectral composition) and emitting the light L2 having the second spectral composition that is different from the first spectral composition.

[0092] The luminescent element 106 can include one or more phosphors that is / are excitable by the light L1 from the light source assembly 102 to emit the light L2 having the second, different, spectral composition. Alternatively or additionally, the luminescent element 106 can comprise at least one inorganic luminescent material, for example at least one inorganic luminescent material comprising an inorganic fluorescent material. Inorganic luminescent materials may benefit from being relatively resistant to change over time as a consequence of repeated exposure to light (in other words may have relatively good lightfastness), heat etc.

[0093] The luminescent material(s) 107; 107A, 107B, 107C can be arranged in, e.g. to form, the luminescent element 106 in any suitable manner. In some embodiments, the luminescent element 106 comprises one or more luminescent materials 107; 107A, 107B, 107C mixed with and / or coated onto a polymer. For example, the luminescent material(s) 107; 107A, 107B, 107C can be mixed with a resin or incorporated into a thermoplastic. This may provide a readily manufacturable way of providing the luminescent element 106.

[0094] In some embodiments, such as shown in FIGs. 5 to 7, the luminescent element 106 comprises a single luminescent material 107. In such embodiments, and referring specifically to FIG. 5, the luminescent element 106 may convert all, or at least substantially all, of the light L1 received from the light source assembly 102 to the light L2.

[0095] For example, the luminescent material 107 is excitable to emit yellow light, and the light L2 emanating from the luminescent element 106 is yellow when the luminescent element 106 is receiving the light L1 from the light source assembly 102.

[0096] In other embodiments, and referring to FIGs. 6 and 7, the luminescent element 106 is configured to allow a fraction L1A of the light L1 from the light source assembly 102 to pass therethrough without exciting the luminescent element 106. In such embodiments, light L1A, L2 emanating from the luminescent element 106 and the housing 104 can comprise the first spectral composition combined with the second spectral composition. Thus, the spectral composition of the light L1A, L2 emanating from the luminescent element 106 can be tuned via mixing the fraction of light L1A from the light source assembly 102 with the light L2 emitted by the excited luminescent element 106.

[0097] For instance, the light source assembly 102 is configured to generate light L1 centered at around 450 nm and the luminescent element 106 is selected to absorb light at that wavelength and re-emit light L2 at around 570 nm.

[0098] In this non-limiting example, part of the original about 450 nm (blue) light L1 from the light source assembly 102 and the about 570 nm (yellow) light L2 from the luminescent element 106, e.g. fluorophore 107 thereof, can now simultaneously leave the luminescent element 106, resulting in a white or off-white appearance of the light L1A, L2 emanating from the luminescent element 106.

[0099] The luminescent element 106 can be configured in any suitable manner in order to allow the fraction L1A of the light L1 from the light source assembly 102 to pass therethrough without exciting the luminescent element 106. For example, this can be implemented via selection of the type / absorption spectrum of the luminescent material 107 in the luminescent element 106; an amount, e.g. concentration of the luminescent material 107 (as schematically represented in FIG. 6); and / or a thickness of the luminescent element 106 (as schematically represented in FIG. 7).

[0100] In some embodiments, such as shown in FIG. 8, the luminescent element 106 comprises a plurality of different luminescent materials 107A, 107B, 107C, e.g. a plurality of different phosphors. In such embodiments, each of the plurality of different luminescent materials 107A can be excited by the light L1 generated by the light source assembly 102 to emit light L2A having a different spectral composition from light L2B, L2C emitted by the other luminescent material(s) 107B, 107C when excited by the light L1 generated by the light source assembly 102.

[0101] Thus, different luminescent materials 107A, 107B, 107C can be used to tune the spectral composition of the light L2A, L2B, L2C emanating from the luminescent element 106. For example, a first luminescent material 107A is excitable to emit red light L2A, a second luminescent material 107B is excitable to emit green light L2B, and a third luminescent material 107C is excitable to emit blue light L2C, when the luminescent element 106 is receiving the light L1 from the light source assembly 102. Thus, white light L2A, L2B, L2C can emanate from the luminescent element 106 and thus from the housing 104.

[0102] It is also noted that the different luminescent materials 107A, 107B, 107C can be used to adjust the color of the luminescent element 106 when the luminescent element 106 is not being excited by the light L1 from the light source assembly 102, for example to help with color-matching with the non-luminescent housing portion 116 adjacent to the luminescent element 106.

[0103] In some embodiments, such as shown in FIG. 9, the luminescent element 106 comprises different regions 106A, 106B having different luminescent properties relative to each other. For example, the region 106B of the luminescent element 106 aligned with the light-transmitting portion(s) 112, 114 can have different luminescent properties relative to region(s) 106A of the luminescent element 106 that is / are not aligned with the light-transmitting portion(s) 112, 114.

[0104] The luminescent properties can be made different in the different regions 106A, 106B in any suitable manner, for example by using a different concentration of luminescent material 107 and / or a different thickness of the luminescent element 106 in the respective regions 106A, 106B.

[0105] 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.

[0106] 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.

[0107] If the term "adapted to" is used in the claims or description, it is noted the term "adapted to" is intended to be equivalent to the term "configured to".

[0108] Any reference signs in the claims should not be construed as limiting the scope.

Examples

Embodiment Construction

[0051]The invention will be described with reference to the Figures.

[0052]It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the apparatus, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, systems and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawings. It should be understood that the Figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts.

[0053]Provided is a household appliance comprising a light source assembly for generating light having a first spectral composition, and a housing containing components of the household appliance. The components housed wit...

FIELD OF THE INVENTION

[0001] The invention relates to a household appliance, such as an air treatment device, having a display that visually conveys information to a user of the household appliance.BACKGROUND OF THE INVENTION

[0002] Displays are widely used in household appliances to provide information to the user, e.g. concerning the operational state of the appliance. In the case of, for instance, an air purifier, the air purifier's display may indicate an operational mode, e.g. fan setting, an indication of the status of certain components included in the air purifier, such as its particle or gas filters etc., and / or other relevant information, e.g. temperature, humidity, and the like.

[0003] Such information can be displayed in different forms, such as using numbers, letters or symbols.

[0004] While it is thus desirable to incorporate display functionality into such household appliances, inclusion of a display can risk cluttering the exterior of the household appliance, and a blank display not showing any information (when none is required to be shown) can risk that the user misinterprets the blank display as meaning the household appliance is faulty. Alternatively or additionally, the display may not visually convey information to the user with sufficient clarity and emphasis.SUMMARY OF THE INVENTION

[0005] The invention is defined by the claims.

[0006] According to examples in accordance with an aspect of the invention, there is provided a household appliance comprising: a light source assembly for generating light having a first spectral composition; a housing containing components of the household appliance, said components including the light source assembly, the housing comprising a luminescent element excitable by the light generated by the light source assembly to emit light having a second spectral composition that is different from the first spectral composition; and at least one optically opaque element arranged between the light source assembly and the luminescent element, at least one light-transmitting portion being defined in the optically opaque element to allow light generated by the light source assembly to pass through the optically opaque element(s) to reach the luminescent element, wherein a defined arrangement of the at least one light-transmitting portion determines a shape of the light emanating from the luminescent element and the housing.

[0007] The shape of the light emanating from the luminescent element and the housing can visually convey information to a user of the household appliance.

[0008] It is noted that the light source assembly, the optically opaque element in which the light-transmitting portion(s) is / are defined, and the luminescent element can be regarded as being included in a display assembly of the household appliance.

[0009] The luminescent element can help to provide a vivid illumination when the luminescent element is receiving the light generated by the light source assembly, particularly when the household appliance is situated in a relatively dark environment.

[0010] The luminescent element can enable various different colors of light to emanate therefrom and thus emanate from the housing of the household appliance. Alternatively or additionally, the color of the light emitted by the luminescent element can be deeper compared to that emitted by, for example, a household device which differs from the one being described only in that no luminescent element is included.

[0011] In some embodiments, the housing comprises a non-luminescent housing portion arranged adjacent to, e.g. at least partially surrounding, the luminescent element, and a color difference, ΔE 00 , as measured using ASTM D2244-23, between the non-luminescent housing portion and at least part of the luminescent element, when the at least part of the luminescent element is not being excited by the light generated by the light source assembly, is 15 or less.

[0012] By the color difference being 15 or less between the non-luminescent housing portion and the at least part of, e.g. an opaque region of, the adjacent luminescent element, the at least part of the luminescent element can be less noticeable, in other words hidden, when not being excited by the light from the light source assembly to emit light.

[0013] Thus, the household appliance can have display functionality which is hidden when not being used, in other words when the luminescent element is not receiving light from the light source assembly, e.g. due to the light source assembly being switched off. Such hiding of the luminescent element by matching its color with the adjacent non-luminescent housing portion can also assist to make the visual change more perceptible when the luminescent element is excited by the light from the light source assembly to emit light.

[0014] In some embodiments, the color difference, ΔE 00 , as measured using ASTM D2244-23, is 5 or less, preferably 4 or less. By the color difference being 5 or less, preferably 4 or less, the at least part of the luminescent element may be even less noticeable when the luminescent element is not being excited by the light from the light source assembly to emit light.

[0015] It is noted that the color difference can be measured using a handheld spectrophotometer, such as the spectro2guide Color Control Handheld Spectrophotometer from BYK, by holding the sensing part of the spectrophotometer against the non-luminescent housing portion, and holding the sensing part against the luminescent element, while the luminescent element is not receiving light from the light source assembly.

[0016] The luminescent element can have any suitable composition provided that the luminescent element is capable of being excited by the light emitted by the light source assembly (having the first spectral composition) and emitting the light having the second spectral composition that is different from the first spectral composition.

[0017] The luminescent element can include one or more phosphors that is / are excitable by the light from the light source assembly to emit the light having the second, different, spectral composition.

[0018] Alternatively or additionally, the luminescent element can comprise at least one inorganic luminescent material, for example at least one inorganic luminescent material comprising an inorganic fluorescent material. Inorganic luminescent materials may benefit from being relatively resistant to change over time as a consequence of repeated exposure to light (in other words may have relatively good lightfastness), heat etc.

[0019] The luminescent material(s) can be arranged in, e.g. to form, the luminescent element in any suitable manner. In some embodiments, the luminescent element comprises one or more luminescent materials mixed with and / or coated onto a polymer. For example, the luminescent material(s) can be mixed with a resin or incorporated into a thermoplastic. This may provide a readily manufacturable way of providing the luminescent element.

[0020] In some embodiments, the luminescent element comprises a plurality of different luminescent materials, e.g. a plurality of different phosphors. In such embodiments, each of the plurality of different luminescent materials can be excited by the light generated by the light source assembly to emit light having a different spectral composition from light emitted by the other luminescent material(s) when excited by the light generated by the light source assembly.

[0021] Thus, different luminescent materials can be used to tune the spectral composition of the light emanating from the luminescent element. Alternatively or additionally, the different luminescent materials can be used to adjust the color of the luminescent element when the luminescent element is not being excited by the light from the light source assembly, for example to help with color-matching with the non-luminescent housing portion adjacent to the luminescent element.

[0022] In some embodiments, the luminescent element is configured to allow a fraction of the light from the light source assembly to pass therethrough without exciting the luminescent element. In such embodiments, light emanating from the luminescent element can comprise the first spectral composition combined with the second spectral composition. Thus, the spectral composition of the light emanating from the luminescent element can be tuned via mixing the fraction of light from the light source assembly with the light emitted by the excited luminescent element.

[0023] For instance, the light source assembly is configured to generate light centered at around 450 nm and the luminescent element is selected to absorb light at that wavelength and re-emit light at around 570 nm.

[0024] In this non-limiting example, part of the original about 450 nm (blue) light from the light source assembly and the about 570 nm (yellow) light from the luminescent element, e.g. fluorophore thereof, can now simultaneously leave the luminescent element, resulting in a white or off-white appearance of the light emanating from the luminescent element.

[0025] In some embodiments, the luminescent element comprises different regions having different luminescent properties relative to each other. For example, the region of the luminescent element aligned with the light-transmitting portion(s) can have different luminescent properties relative to region(s) of the luminescent element that is / are not aligned with the light-transmitting portion(s).

[0026] The luminescent properties can be made different in the different regions in any suitable manner, for example by using a different concentration of luminescent material and / or a different thickness of the luminescent element in the respective regions.

[0027] In embodiments in which the color difference is 15 or less, e.g. 5 or less, preferably 4 or less, between the non-luminescent housing portion and the at least part of the adjacent luminescent element, this maximum color difference may apply in respect of at least one of the regions, e.g. an opaque region, of the luminescent element.

[0028] More generally, the luminescent element may include at least one fluorescent material that is caused to fluoresce by the light generated by the light source assembly. For example, the luminescent material(s) of the luminescent element comprise a fluorophore, e.g. an inorganic, for instance garnet-based, fluorophore.

[0029] A non-limiting example of a garnet-based fluorophore is YAG:Ce (Y 3 Al 5 O 12 :Ce), which absorbs light whose wavelength is about 450 nm, and re-emits light whose wavelength is about 570 nm.

[0030] More generally, examples of luminescent materials which may be included in the luminescent element include garnet-based YAG:Ce (Y 3 Al 5 O 12 :Ce) materials, lorthosilicates, nitrides, oxinitrides, uAG, phosphates, luminescent quantum dots and / or nanocrystals such as CuInS 2 , ZnSe, CdSe, ZnS, InP, PbSe, and PbS.

[0031] In some embodiments, the defined arrangement of the at least one light-transmitting portion comprises symbol-defining portion(s), with the symbol-defining portion(s) determining symbol shape(s) of the light emanating from the luminescent element. Such symbol shape(s) can visually convey information to the user of the household appliance when the symbol-defining portion(s) is / are transmitting light from the light source assembly to cause the symbol shaped-light to emanate from the luminescent element.

[0032] As an alternative or in addition to the symbol-defining portion(s), the defined arrangement of the at least one light-transmitting portion can comprise alphanumeric character-defining portions, with the alphanumeric character-defining portions determining alphanumeric character shapes of the light emitted by the luminescent element.

[0033] Such alphanumeric character shape(s) can visually convey numerical and / or textual information to a user of the household appliance when the alphanumeric character-defining portion(s) is / are transmitting light from the light source assembly to cause the alphanumeric character-shaped light to emanate from the luminescent element.

[0034] In some embodiments, the alphanumeric character-defining portions comprise numeral-defining portions, with the numeral-defining portions determining numeral shapes of the light emanating from the luminescent element.

[0035] The light-transmitting portion(s) can be realized in any suitable manner. In some embodiments, the optically opaque element includes an optically opaque layer in which light-transmitting region(s) is / are defined.

[0036] Defining the light-transmitting region(s) in the optically opaque layer can, for example, be implemented via selective removal of the region(s) of the optically opaque layer. Such selective removal can, for instance, be achieved using an etching process.

[0037] In some embodiments, light-transmitting portion(s) defined in the optically opaque element is / are configured so that only the wavelength(s) of light corresponding to the emission of the light source assembly is / are transmitted therethrough, while all other wavelengths are absorbed.

[0038] This may help to achieve a more homogenous appearance throughout the surface of the luminescent element, particularly when an "off state" is adopted in which the luminescent element is not receiving light from the light source assembly.

[0039] As an alternative or in addition to the optically opaque layer, the optically opaque element can include an intermediate member arranged between the light source assembly and the luminescent element, with at least one light channel being defined in the intermediate member. In such embodiments, the at least one light channel can channel light from the light source assembly to the luminescent element. Such light channel(s) can provide a convenient way of controlling incidence of light from the light source assembly on the luminescent element, particularly in embodiments in which it is desired for the light emanating from the luminescent element to be in the shape of numerals.

[0040] In embodiments in which the at least one light channel comprises a plurality of light channels, the plurality of light channels can include one or more sets of numeral-defining light channels, with each set of numeral-defining light channels comprising seven light channels.

[0041] In such embodiments, the seven light channels can be arranged so that illuminating two or more of the seven light channels permits each of the numerals 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 to be presented.

[0042] In such embodiments, the light source assembly can, for example, include a light source, e.g. a light source in the form of a light emitting diode, for illuminating one of the numeral-defining portions, so that seven light sources are provided for each set.

[0043] In some embodiments, the, e.g. each of the, at least one light channel is at least partially delimited by an optically reflective surface. Such an optically reflective surface can assist to ensure optically efficient transmission of light from the light source assembly to the luminescent element via the light channel(s).

[0044] The optically reflective surface can be implemented in any suitable manner, for example by a white pigment coating the wall surrounding the respective light channel and / or by the optically reflective surface comprising an aluminum-based reflective material.

[0045] The light source(s) included in the light source assembly can be of any suitable type. Particular mention is made of light emitting diode(s), LED(s), being included in the light source assembly, since LED(s) can be selected to emit light having a wavelength that excites luminescent material(s) included in the luminescent element.

[0046] In general terms, the spectral composition of the light generated by the light source assembly can be chosen such that it corresponds to absorption peak(s) of the luminescent material(s) included in the luminescent element. Preferably, blue light-emitting LED(s) is / are included in the light source assembly.

[0047] In some embodiments, the household appliance is an air treatment device, for example an air treatment device comprising an air purifier. In such embodiments, the components housed within the housing can include an air displacement assembly, e.g. fan unit, and / or air purification element(s), such as filter(s), for purifying air.

[0048] The principles of the present disclosure may be beneficial when applied in household appliances in general, but especially in air treatment devices, such as air purifiers, air dehumidifiers, air humidifiers or comfort fans, in which sleek display functionality is desired by consumers.

[0049] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter.BRIEF DESCRIPTION OF THE DRAWINGS

[0050] For a better understanding of the invention, and to show more clearly how it may be carried into effect, reference will now be made, by way of example only, to the accompanying drawings, in which: FIG. 1 schematically depicts part of a household appliance according to an example; FIG. 2 shows symbol shapes and alphanumeric shapes of light emanating from a luminescent element included in such a household appliance; FIG. 3 shows part of a household appliance according to another example; FIG. 4A depicts light emanating from a household appliance's luminescent element when the luminescent element is excited by light from a light source assembly included in the household appliance; FIG. 4B depicts the luminescent element not being excited by the light from the light source assembly in the household appliance; FIGs. 5 to 8 schematically depict various examples of the household appliance's luminescent element and adjacent non-luminescent housing portion; and FIG. 9 schematically depicts part of a household appliance according to a further example. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0051] The invention will be described with reference to the Figures.

[0052] It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the apparatus, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, systems and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawings. It should be understood that the Figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts.

[0053] Provided is a household appliance comprising a light source assembly for generating light having a first spectral composition, and a housing containing components of the household appliance. The components housed within the housing include the light source assembly. The housing comprises a luminescent element excitable by the light generated by the light source assembly to emit light having a second spectral composition that is different from the first spectral composition. At least one optically opaque element is arranged between the light source assembly and the luminescent element, with at least one light-transmitting portion being defined in the optically opaque element to allow light generated by the light source assembly to pass through the optically opaque element to reach the luminescent element. A defined arrangement of the at least one light-transmitting portion determines a shape of the light emanating from the luminescent element and the housing that visually conveys information to a user of the household appliance.

[0054] FIG. 1 provides a schematic cross-sectional view of part of a household appliance 100 according to an example. The household appliance 100 comprises a light source assembly 102 that is housed within the household appliance's 100 housing 104.

[0055] It is noted that the housing 104 can house components (not visible in FIG. 1) other than the light source assembly 102.

[0056] The household appliance 100 can be of any suitable type. In some embodiments, the household appliance 100 is an air treatment device, for example an air treatment device comprising an air purifier. In such embodiments, the components housed within the housing 104 can include an air displacement assembly, e.g. fan unit, and / or air purification element(s), such as filter(s), for purifying air.

[0057] More generally, the light source assembly 102 is configured to generate light L1 having a first spectral composition, and the housing 104 comprises a luminescent element 106 excitable by the light L1 generated by the light source assembly 102 to emit light L2 having a second spectral composition that is different from the first spectral composition. The luminescent element 106 can help to provide a vivid illumination when the luminescent element 106 is receiving the light L1 generated by the light source assembly 102, particularly when the household appliance 100 is situated in a relatively dark environment.

[0058] The color of the light L2 emitted by the luminescent element 106 can be deeper compared to that emitted from, for example, a household device which differs from the one being described only in that no luminescent element 106 is included. Moreover, and as explained in more detail herein below, the luminescent element 106 can enable various different colors of light L2 to emanate therefrom and thus emanate from the housing 104 of the household appliance 100.

[0059] As shown in FIG. 1, at least one optically opaque element 108, 110 is arranged between the light source assembly 102 and the luminescent element 106, with at least one light-transmitting portion 112, 114 being defined in the optically opaque element(s) 108, 110 to allow the light L1 generated by the light source assembly 102 to pass through the optically opaque element(s) 108, 110 to reach the luminescent element 106.

[0060] A defined arrangement of the at least one light-transmitting portion 112, 114 determines a shape of the light L2 emanating from the luminescent element 106 and the housing 104. The shape of the light L2 emanating from the luminescent element 106 and the housing 104 can visually convey information to a user of the household appliance 100.

[0061] The purpose of the optically opaque element 108, 110 is to prevent the light L1 from hitting the luminescent element 106 at all positions but those where the shape(s) to be displayed is / are located.

[0062] The light-transmitting portion(s) 112, 114 can be realized in any suitable manner. In some embodiments, such as shown in FIG. 1, the optically opaque element 110, 112 includes an optically opaque layer 110 in which light-transmitting region(s) 114 is / are defined.

[0063] Defining the light-transmitting region(s) 114 in the optically opaque layer 110 can, for example, be implemented via selective removal of the region(s) of the optically opaque layer 110. Such selective removal can, for instance, be achieved using an etching process.

[0064] The optically opaque layer 110 can be formed in any suitable manner. The optically opaque layer 110 may, for instance, comprise a mylar film, a layer of ink, e.g. a layer of ink printed on a surface of the luminescent element 106 that faces the light source assembly 102.

[0065] In some embodiments, light-transmitting portion(s) 112, 114 defined in the optically opaque element 108, 110 may be configured so that only the wavelength(s) of light corresponding to the emission of the light source assembly 102 is / are transmitted therethrough, while all other wavelengths are absorbed.

[0066] This may help to achieve a more homogenous appearance throughout the surface of the luminescent element 106, particularly when an "off state" is adopted in which the luminescent element 106 is not receiving light L1 from the light source assembly 102.

[0067] This can be achieved by, for example, the optically opaque layer 110 including pigment(s) in the light-transmitting region(s) 114 thereof whose absorption properties mean that only the wavelength(s) of light corresponding to the emission of the light source assembly 102 is / are transmitted therethrough.

[0068] As an alternative or in addition to the optically opaque layer 110, the optically opaque element 108, 110 can include an intermediate member 108 arranged between the light source assembly 102 and the luminescent element 106, with at least one light channel 112 being defined in the intermediate member 108. In such embodiments, the at least one light channel 112 can channel light L1 from the light source assembly 102 to the luminescent element 106. Such light channel(s) 112 can provide a convenient way of controlling incidence of light L1 from the light source assembly 102 on the luminescent element 106, particularly in embodiments in which it is desired for the light emanating from the luminescent element 106 to be in the shape of numerals, as explained in more detail herein below.

[0069] It is noted that in embodiments in which the optically opaque element 108, 110 includes the intermediate member 108 and the optically opaque layer 110, the light channel(s) 112 can be arranged to channel the light L1 from the light source assembly 102 to the light-transmitting region(s) 114 defined in the optically opaque layer 110.

[0070] In some embodiments, and still referring to FIG. 1, the, e.g. each of the, at least one light channel 112 is at least partially delimited by an optically reflective surface 113. Such an optically reflective surface 113 can assist to ensure optically efficient transmission of light L1 from the light source assembly 102 to the luminescent element 106 via the light channel(s) 112.

[0071] The optically reflective surface 113 can be implemented in any suitable manner, for example by a white pigment coating the wall surrounding the respective light channel 112 and / or by the optically reflective surface 113 comprising an aluminum-based reflective material.

[0072] In some embodiments, and referring to the upper part of FIG. 2, the defined arrangement of the at least one light-transmitting portion 112, 114 comprises symbol-defining portion(s), with the symbol-defining portion(s) determining symbol shape(s) 114A of the light emanating from the luminescent element 106. Such symbol shape(s) 114A can visually convey information to a user of the household appliance 100 when the symbol-defining portion(s) is / are transmitting light L1 from the light source assembly 102 to cause the symbol shaped-light to emanate from the luminescent element 106.

[0073] In the non-limiting example provided at the top left part of FIG. 2, the symbol-defining portion(s) determine a symbol shape 114A in the form of a capital letter "A" with two vertical lines on each side of the "A". This can, for example, denote an operational mode of the household appliance 100.

[0074] In the non-limiting example provided at the top right part of FIG. 2, the symbol-defining portion(s) determine a symbol shape 114A in the form of a locked padlock. The latter can, for instance, indicate a locked mode of the household appliance 100, e.g. a locked mode of a user input interface included in the household appliance 100.

[0075] As an alternative or in addition to the symbol-defining portion(s), the defined arrangement of the at least one light-transmitting portion 112, 114 can comprise alphanumeric character-defining portions, with the alphanumeric character-defining portions determining alphanumeric character shapes 114B of the light emanating from the luminescent element 106, as shown in the bottom part of FIG. 2.

[0076] Such alphanumeric character shape(s) 114B can visually convey numerical and / or textual information to a user of the household appliance 100 when the alphanumeric character-defining portion(s) is / are transmitting light L1 from the light source assembly 102 to cause the alphanumeric character-shaped light to emanate from the luminescent element 106.

[0077] In some embodiments, the alphanumeric character-defining portions comprise numeral-defining portions, with the numeral-defining portions determining numeral shapes of the light emanating from the luminescent element 106.

[0078] In embodiments in which the at least one light channel 112 comprises a plurality of light channels 112, such as shown in FIG. 3, the plurality of light channels 112 can include one or more sets of numeral-defining light channels 112, with each set of numeral-defining light channels comprising seven light channels 112.

[0079] In such embodiments, the seven light channels 112 can be arranged so that illuminating two or more of the seven light channels 112 permits each of the numerals 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 to be presented.

[0080] In such embodiments, the light source assembly 102 can, for example, include a light source 115, e.g. a light source 115 in the form of a light emitting diode, for illuminating one of the numeral-defining portions, so that seven light sources 115 are provided for each set.

[0081] It is noted more generally that the light source(s) 115 included in the light source assembly 102 can be of any suitable type. Particular mention is made of light emitting diode(s), LED(s), being included in the light source assembly 102, since LED(s) can be selected to emit light L1 having a wavelength that excites luminescent material(s) included in the luminescent element 106.

[0082] In general terms, the spectral composition of the light L1 generated by the light source assembly 102 can be chosen such that it corresponds to absorption peak(s) of the luminescent material(s) included in the luminescent element 106. Preferably, blue light-emitting LED(s) is / are included in the light source assembly 102.

[0083] In some embodiments, and referring again to FIG. 1, the housing 104 comprises a non-luminescent housing portion 116 arranged adjacent to, e.g. surrounding, the luminescent element 106, and a color difference, ΔE 00 , as measured using ASTM D2244-23, between the non-luminescent housing portion 116 and at least part of the luminescent element 106, when the luminescent element 106 is not being excited by the light L1 generated by the light source assembly 102, is 15 or less.

[0084] By the color difference being 15 or less between the non-luminescent housing portion 116 and the at least part of, e.g. the entirety of, the adjacent luminescent element 106, the luminescent element 106 can be less noticeable, in other words hidden, when not being excited by the light L1 from the light source assembly 102 to emit light.

[0085] Thus, the household appliance 100 can have display functionality which is hidden when not being used, in other words when the luminescent element 106 is not receiving light L1 from the light source assembly 102, e.g. due to the light source assembly 102 being switched off. Such hiding of the luminescent element 106 by matching its color with the adjacent non-luminescent housing portion 116 can also assist to make the visual change more perceptible when the luminescent element 106 is excited by the light L1 from the light source assembly 102 to emit light L2.

[0086] A non-limiting illustrative example of this is schematically shown in FIGs. 4A and 4B. In FIG. 4A, the luminescent element 106 is being excited by the light source assembly 102 to emit light L2, in this case in the form of numeral shapes 114B, and the color of the light emanating from the luminescent element 106 contrasts with the color of the non-luminescent housing portion 116. However, in FIG. 4B, the luminescent element 106 is no longer receiving light L1 from the light source assembly 102, e.g. due to the light source assembly 102 being switched off, and the minimal color difference between the non-emitting luminescent element 106 and the adjacent non-luminescent housing portion 116 hides the display functionality.

[0087] For instance, a luminescent material included in the luminescent element 106 may be a garnet-based YAG:Ce (Y 3 Al 5 O 12 :Ce) material. In this non-limiting example, under normal ambient light (without the light L1 generated by the light source assembly 102), the luminescent element 106 appears yellowish / orange, which matches the color of the non-luminescent housing portion 116.

[0088] In some embodiments, the color difference, ΔE 00 , as measured using ASTM D2244-23, is 5 or less, preferably 4 or less. By the color difference being 5 or less, preferably 4 or less, the luminescent element 106 may be even less noticeable when the luminescent element 106 is not being excited by the light L1 from the light source assembly 102 to emit light L2.

[0089] The manner in which this color matching is achieved is not particularly limited. In some embodiments, and referring to FIGs. 5 to 8, pigment(s) 117, and amount(s) of the pigment(s) 117, included in the non-luminescent housing portion 116, and luminescent material(s) 107; 107A, 107B, 107C, and amounts of the luminescent material(s) 107; 107A, 107B, 107C included in the luminescent element 106 can be selected to achieve the color difference of 15 or less, preferably 5 or less, and most preferably 4 or less. The latter can be directly and positively verified using the method set out in ASTM D2244-23.

[0090] It is noted that the color difference can be measured using a handheld spectrophotometer, such as the spectro2guide Color Control Handheld Spectrophotometer from BYK, by holding the sensing part of the spectrophotometer against the non-luminescent housing portion 116, and holding the sensing part against the luminescent element 106, while the luminescent element 106 is not receiving light from the light source assembly 102.

[0091] More generally, the luminescent element 106 can have any suitable composition provided that the luminescent element 106 is capable of being excited by the light L1 emitted by the light source assembly 102 (having the first spectral composition) and emitting the light L2 having the second spectral composition that is different from the first spectral composition.

[0092] The luminescent element 106 can include one or more phosphors that is / are excitable by the light L1 from the light source assembly 102 to emit the light L2 having the second, different, spectral composition. Alternatively or additionally, the luminescent element 106 can comprise at least one inorganic luminescent material, for example at least one inorganic luminescent material comprising an inorganic fluorescent material. Inorganic luminescent materials may benefit from being relatively resistant to change over time as a consequence of repeated exposure to light (in other words may have relatively good lightfastness), heat etc.

[0093] The luminescent material(s) 107; 107A, 107B, 107C can be arranged in, e.g. to form, the luminescent element 106 in any suitable manner. In some embodiments, the luminescent element 106 comprises one or more luminescent materials 107; 107A, 107B, 107C mixed with and / or coated onto a polymer. For example, the luminescent material(s) 107; 107A, 107B, 107C can be mixed with a resin or incorporated into a thermoplastic. This may provide a readily manufacturable way of providing the luminescent element 106.

[0094] In some embodiments, such as shown in FIGs. 5 to 7, the luminescent element 106 comprises a single luminescent material 107. In such embodiments, and referring specifically to FIG. 5, the luminescent element 106 may convert all, or at least substantially all, of the light L1 received from the light source assembly 102 to the light L2.

[0095] For example, the luminescent material 107 is excitable to emit yellow light, and the light L2 emanating from the luminescent element 106 is yellow when the luminescent element 106 is receiving the light L1 from the light source assembly 102.

[0096] In other embodiments, and referring to FIGs. 6 and 7, the luminescent element 106 is configured to allow a fraction L1A of the light L1 from the light source assembly 102 to pass therethrough without exciting the luminescent element 106. In such embodiments, light L1A, L2 emanating from the luminescent element 106 and the housing 104 can comprise the first spectral composition combined with the second spectral composition. Thus, the spectral composition of the light L1A, L2 emanating from the luminescent element 106 can be tuned via mixing the fraction of light L1A from the light source assembly 102 with the light L2 emitted by the excited luminescent element 106.

[0097] For instance, the light source assembly 102 is configured to generate light L1 centered at around 450 nm and the luminescent element 106 is selected to absorb light at that wavelength and re-emit light L2 at around 570 nm.

[0098] In this non-limiting example, part of the original about 450 nm (blue) light L1 from the light source assembly 102 and the about 570 nm (yellow) light L2 from the luminescent element 106, e.g. fluorophore 107 thereof, can now simultaneously leave the luminescent element 106, resulting in a white or off-white appearance of the light L1A, L2 emanating from the luminescent element 106.

[0099] The luminescent element 106 can be configured in any suitable manner in order to allow the fraction L1A of the light L1 from the light source assembly 102 to pass therethrough without exciting the luminescent element 106. For example, this can be implemented via selection of the type / absorption spectrum of the luminescent material 107 in the luminescent element 106; an amount, e.g. concentration of the luminescent material 107 (as schematically represented in FIG. 6); and / or a thickness of the luminescent element 106 (as schematically represented in FIG. 7).

[0100] In some embodiments, such as shown in FIG. 8, the luminescent element 106 comprises a plurality of different luminescent materials 107A, 107B, 107C, e.g. a plurality of different phosphors. In such embodiments, each of the plurality of different luminescent materials 107A can be excited by the light L1 generated by the light source assembly 102 to emit light L2A having a different spectral composition from light L2B, L2C emitted by the other luminescent material(s) 107B, 107C when excited by the light L1 generated by the light source assembly 102.

[0101] Thus, different luminescent materials 107A, 107B, 107C can be used to tune the spectral composition of the light L2A, L2B, L2C emanating from the luminescent element 106. For example, a first luminescent material 107A is excitable to emit red light L2A, a second luminescent material 107B is excitable to emit green light L2B, and a third luminescent material 107C is excitable to emit blue light L2C, when the luminescent element 106 is receiving the light L1 from the light source assembly 102. Thus, white light L2A, L2B, L2C can emanate from the luminescent element 106 and thus from the housing 104.

[0102] It is also noted that the different luminescent materials 107A, 107B, 107C can be used to adjust the color of the luminescent element 106 when the luminescent element 106 is not being excited by the light L1 from the light source assembly 102, for example to help with color-matching with the non-luminescent housing portion 116 adjacent to the luminescent element 106.

[0103] In some embodiments, such as shown in FIG. 9, the luminescent element 106 comprises different regions 106A, 106B having different luminescent properties relative to each other. For example, the region 106B of the luminescent element 106 aligned with the light-transmitting portion(s) 112, 114 can have different luminescent properties relative to region(s) 106A of the luminescent element 106 that is / are not aligned with the light-transmitting portion(s) 112, 114.

[0104] The luminescent properties can be made different in the different regions 106A, 106B in any suitable manner, for example by using a different concentration of luminescent material 107 and / or a different thickness of the luminescent element 106 in the respective regions 106A, 106B.

[0105] 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.

[0106] 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.

[0107] If the term "adapted to" is used in the claims or description, it is noted the term "adapted to" is intended to be equivalent to the term "configured to".

[0108] Any reference signs in the claims should not be construed as limiting the scope.

Examples

Embodiment Construction

[0051]The invention will be described with reference to the Figures.

[0052]It should be understood that the detailed description and specific examples, while indicating exemplary embodiments of the apparatus, systems and methods, are intended for purposes of illustration only and are not intended to limit the scope of the invention. These and other features, aspects, and advantages of the apparatus, systems and methods of the present invention will become better understood from the following description, appended claims, and accompanying drawings. It should be understood that the Figures are merely schematic and are not drawn to scale. It should also be understood that the same reference numerals are used throughout the Figures to indicate the same or similar parts.

[0053]Provided is a household appliance comprising a light source assembly for generating light having a first spectral composition, and a housing containing components of the household appliance. The components housed wit...

Claims

1. A household appliance (100) comprising: a light source assembly (102) for generating light (L1) having a first spectral composition; a housing (104) containing components of the household appliance, said components including the light source assembly, the housing comprising a luminescent element (106) excitable by the light generated by the light source assembly to emit light (L2) having a second spectral composition that is different from the first spectral composition; and at least one optically opaque element (108, 110) arranged between the light source assembly and the luminescent element, at least one light-transmitting portion (112, 114) being defined in the optically opaque element to allow light generated by the light source assembly to pass through the optically opaque element(s) to reach the luminescent element, wherein a defined arrangement of the at least one light-transmitting portion determines a shape of the light emanating from the luminescent element and the housing.

2. The household appliance (100) according to claim 1, wherein the housing (104) comprises a non-luminescent housing portion (116) arranged adjacent to the luminescent element (106), wherein a color difference, ΔE00, as measured using ASTM D2244-23, between the non-luminescent housing portion and at least part of the luminescent element, when the at least part of the luminescent element is not being excited by the light (L1) generated by the light source (102), is 15 or less.

3. The household appliance (100) according to claim 2, wherein the color difference, ΔE00, as measured using ASTM D2244-23, is 5 or less, preferably 4 or less.

4. The household appliance (100) according to any one of claims 1 to 3, wherein the luminescent element (106) comprises a plurality of different luminescent materials (107A, 107B, 107C).

5. The household appliance (100) according to any one of claims 1 to 4, wherein the luminescent element (106) is configured to allow a fraction of the light (L1A) from the light source assembly (102) to pass therethrough without exciting the luminescent element.

6. The household appliance (100) according to any one of claims 1 to 5, wherein the luminescent element (106) comprises different regions (106A, 106B) having different luminescent properties relative to each other.

7. The household appliance (100) according to any one of claims 1 to 6, wherein the defined arrangement of the at least one light-transmitting portion (112, 114) comprises symbol-defining portion(s), the symbol-defining portion(s) determining symbol shape(s) (114A) of the light emanating from the luminescent element (106) and the housing (104).

8. The household appliance (100) according to any one of claims 1 to 7, wherein the defined arrangement of the at least one light-transmitting portion (112, 114) comprises alphanumeric character-defining portions, the alphanumeric character-defining portions determining alphanumeric character shapes (114B) of the light emanating from the luminescent element (106) and the housing (104).

9. The household appliance (100) according to any one of claims 1 to 8, comprising an intermediate member (108) arranged between the light source assembly (102) and the luminescent element (106), at least one light channel (112) being defined in the intermediate member, the at least one light channel being arranged to channel light from the light source assembly to the luminescent element.

10. The household appliance (100) according to claim 9, wherein the at least one light channel (112) is at least partially delimited by an optically reflective surface (113).

11. The household appliance (100) according to any one of claims 1 to 10, wherein the luminescent element (106) comprises at least one fluorescent material that is caused to fluoresce by the light (L1) generated by the light source assembly (102).

12. The household appliance (100) according to any one of claims 1 to 11, wherein the luminescent element (106) comprises one or more luminescent materials (107; 107A, 107B, 107C) mixed with and / or coated onto a polymer.

13. The household appliance (100) according to any one of claims 1 to 12, wherein the luminescent element (106) comprises at least one inorganic luminescent material; optionally wherein the at least one inorganic luminescent material comprises an inorganic fluorescent material.

14. The household appliance (100) according to any one of claims 1 to 13, wherein the light source assembly (102) comprises at least one light emitting diode; optionally wherein the at least one light emitting diode comprises one or more blue light emitting diodes.

15. The household appliance (100) according to any one of claims 1 to 14, wherein the household appliance is an air treatment device; optionally wherein the air treatment device comprises an air purifier.

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