Patent Application
20200324694
The present disclosure relates to edge-lit reading lamps for automobiles. More particularly, the present disclosure relates to an edge-lit reading lamp that includes an anti-glare plate and a diffuser plate for reducing visible blue light.
Reading lamps are used in a variety of locations. For example, an automobile may include interior reading lamps. An interior reading lamp is sometimes referred to as a map light. The map light provides a focused beam of light for illuminating a specific object, such as a map. In contrast, an interior dome light illuminates the entire interior cabin of a vehicle.
There are various factors that contribute to a comfortable reading environment for an individual. For example, excessive blue light may cause digital eye strain. Blue light is the portion of the visible light spectrum with the shortest wavelengths and highest energy. As a result, visible blue light scatters more easily than other visible light. Thus, reading lamps that emit significant amounts of blue light may contribute to digital eye strain. In addition to the issues caused by blue light, reading lamps that provide excessive light or glare may result in eye fatigue. Furthermore, some individuals may also find some reading lights produce low quality light.
Thus, while current reading lamps achieve their intended purpose, there is a need for new and improved reading lamps that provide high quality light.
According to several aspects an edge-lit reading lamp for an automobile is disclosed. The edge-lit reading lamp includes a housing having an open end and one or more sidewalls and a plurality of light emitting diodes (LEDs) disposed along the one or more sidewalls of the housing. The plurality of LEDs are configured to emit visible light, where the visible light includes blue visible light. The edge-lit reading lamp also includes a light guide plate surrounded by the plurality of LEDs and a diffuser plate positioned to receive the visible light emitted by the plurality of LEDs. The diffuser plate includes light diffusion particles configured to adsorb at least enough of the visible blue light from the visible light emitted by the plurality of LEDs to result in a visible light spectrum including an amount of the visible blue light that is equal to or less than a remainder of color frequencies in the visible light spectrum. The edge-lit reading lamp also includes an anti-glare plate having a plurality of light scattering microstructures disposed along a surface of the anti-glare plate that are oriented to face away from the visible light generated by the plurality of LEDs.
In one aspect of the disclosure, the anti-glare plate is configured to reduce a unified glare rating (UGR) of the visible light generated by the plurality of LEDs that exits the reading lamp to a satisfactory level.
In another aspect of the disclosure, the satisfactory level is 19.
In yet another aspect of the disclosure, the plurality of light scattering microstructures are nano-sized.
In one aspect of the disclosure, the plurality of light scattering microstructures each include a substantially rounded profile.
In another aspect of the disclosure, the anti-glare plate is positioned within the open end of the housing.
In yet another aspect of the disclosure, the plurality of LEDs are white LEDs.
In one aspect of the disclosure, the edge-lit reading lamp further comprises a light reflective film disposed along an inner bottom surface of the housing.
In another aspect of the disclosure, the light reflective film includes a thickness of about 0.3 millimeters.
In yet another aspect of the disclosure, the light guide plate includes a thickness of about two millimeters.
In one aspect of the disclosure, the diffuser plate adsorbs enough visible blue light to result in the edge-lit reading lamp emitting less of the visible blue light when compared to the remainder of color frequencies in the visible light spectrum.
In another aspect of the disclosure, the diffuser plate includes a thickness of about 0.3 millimeters.
In yet another aspect of the disclosure, the anti-glare plate includes a thickness of about 0.8 millimeters.
In one aspect of the disclosure, the housing includes a height of about four millimeters.
In another aspect of the disclosure, the light diffusion particles are constructed of at least one of the following: titanium dioxide (TiO2), silicon dioxide (SiO2), aluminum oxide (A1203), hollow SiO2, zinc oxide (ZrO2), and cerium oxide (CeO2), and where the light diffusion particles include a particle diameter of ranging from about 5 nanometers to about 200 nanometers.
In one aspect of the disclosure, an edge-lit reading lamp is disclosed. The edge-lit reading lamp includes a housing having an open end and one or more sidewalls, where the housing includes a height of about four millimeters. The edge-lit reading lamp also includes a plurality of white LEDs disposed along the one or more sidewalls of the housing. The plurality of white LEDs are configured to emit visible light, and the visible light includes blue visible light. The edge-lit reading lamp also includes a light guide plate surrounded by the plurality of white LEDs and a diffuser plate positioned to receive the visible light emitted by the plurality of white LEDs. The diffuser plate includes light diffusion particles configured to adsorb at least enough of the visible blue light from the visible light emitted by the plurality of white LEDs to result in a visible light spectrum including an amount of the visible blue light that is equal to or less than a remainder of color frequencies in the visible light spectrum. The edge-lit reading lamp also includes an anti-glare plate having a plurality of light scattering microstructures disposed along a surface of the anti-glare plate that are oriented to face away from the visible light generated by the plurality of LEDs.
In one aspect of the disclosure, the anti-glare plate is configured to reduce a unified glare rating (UGR) of the visible light generated by the plurality of LEDs that exits the reading lamp to a satisfactory level.
In another aspect of the disclosure, the satisfactory level is 19.
In yet another aspect of the disclosure, the plurality of light scattering microstructures are nano-sized.
In still another aspect of the disclosure, the light diffusion particles are constructed of at least one of the following: titanium dioxide (TiO2), silicon dioxide (SiO2), aluminum oxide (Al2O3), hollow SiO2, zinc oxide (ZrO2), and cerium oxide (CeO2), and where the light diffusion particles include a particle diameter of ranging from about 5 nanometers to about 200 nanometers.
Further areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way.
The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses.
Referring to
In one embodiment, the LEDs 20 may be white LEDs. However, it is to be appreciated that the reading lamp 18 is not limited to a specific type of LED, and in an alternative embodiment red, blue, and green (RGB) LEDs may be used instead. White LEDs tend to emit a large amount of visible blue light, which includes a wavelength ranging from about 450 to about 495 nanometers. However, as explained below, the diffusion plate 26 is configured to reduce the amount of visible blue light emitted by the white LEDs 20. Therefore, even if white LEDs are employed, the reading lamp 18 still emits relatively low levels of visible blue light.
The reading lamp 18 provides a focused beam of visible light and may be used in a variety of applications. Some examples of applications include, but are not limited to, automobiles, aircraft, home appliances, and in manufacturing environments. In one specific application, the reading lamp 18 may be a map light for an automobile such as a sport utility vehicle, van, or sedan.
The housing 10 of the reading lamp 18 is relatively compact and requires significantly less packaging space when compared to some other types of conventional reading lamps. Referring to
Continuing to refer to
The light guide plate 24 is disposed directly above the light reflective film 22 and is located entirely within the housing 10. The light guide plate 24 is positioned substantially parallel with respect to the diffuser plate 26 and is surrounded by the plurality of LEDs 20. Therefore, the visible light emitted by the LEDs 20 is transmitted to the light guide plate 24. The light guide plate 24 then directs the visible light generated by the LEDs 20 in a direction towards the diffuser plate 26. In one non-limiting embodiment, the light guide plate 24 is constructed of poly(methyl methacrylate) (PMMA) and includes a thickness of about two millimeters.
Referring to
The diffusion plate 26 is configured to reduce the amount of visible blue light from the visible light generated by the plurality of LEDs 20. It is to be appreciated that visible blue light may contribute to digital eye strain. In addition to reducing the amount of visible blue light, the diffusion plate 26 also increases the amount of visible light emitted in other color frequencies as well. Referring now to
Referring now to
Table One, which is reproduced below, compares various characteristics of the visible light generated by a conventional reading lamp and an exemplary reading lamp 18 that includes a diffuser plate 26 with the spectral properties shown in
The characteristics listed in Table One include a Correlated Color Temperature (CCT), a luminous efficiency (Im) that is expressed as a percentage, a Color Rendering Index (CRI), a Color Quality Scale (CQS), and an R value R9. The CCT rating of a lamp indicates the color appearance. Specifically, the CCT rating indicates if a light source generates visible light having a warm or cool appearance. Light sources with a CCT rating below 3200 Kelvin are usually classified as warm, while those with a CCT rating above 4000 Kelvin are usually classified as cool in appearance. The CRI defines how accurately a light source reproduces an illuminated object's color when compared to a reference light source of comparable color temperature. The CRI is a unitless quantity, where higher CRI values correspond to better color rendering, where the maximum value is 100. The CQS is an alternative to the CRI. However, instead of only eight unsaturated or pastel colors, the CQS evaluates fifteen colors that more accurately span the range of object colors. The CQS also considers chromatic discrimination and human preference. Similar to the CRI, the maximum value of the CQS is also 100.
The R value R9 is now explained. The CRI includes fifteen colors ranging from R1 to R15. However, the CRI score is calculated by averaging the scores of only the first eight colors (R1-R8), which are a variety of unsaturated, pastel colors. Colors R9-R15 are not calculated into the CRI score but may be considered individually. R9 correlates to a strong red color. As an example of the remaining colors R9-R15, the color R10 correlates to a strong yellow, while color R8 correlates to a light reddish purple.
As seen in Table One, the CCT of both reading lamps are above 3200 Kelvin and therefore do not generate visible light that includes a warm appearance. However, the conventional reading lamp includes a CCT that is above 4000 Kelvin, and therefore emits light that is cool in appearance. Furthermore, the reading lamp 18 provides improved CRI and CQS scores. Moreover, the R value indicates the disclosed reading lamp 18 also emits significantly more red light when compared to the conventional reading lamp.
Referring back to
The anti-glare plate 28 is configured to reduce the unified glare rating (UGR) of the visible light generated by the LEDs 20 that exits the reading lamp to a satisfactory level. Specifically, the reading lamp 18 produces visible light having a UGR of 19 or less. The UGR is a method of calculating glare from luminaires, light through windows, and bright light sources. A UGR of 19 or less indicates that a luminaire does not create uncomfortable glare for a user and provides a satisfactory level of glare. It is to be appreciated that some conventional reading lamps that are presently used may have relatively high UGRs of 26 or more. A UGR of 26 provides an uncomfortable glare to a user. Therefore, in some instances, the anti-glare plate 28 reduces the UGR from an uncomfortable level to a satisfactory level.
The anti-glare plate 28 includes an upper surface 52 is exposed to the environment and a lower surface 54 that opposes the diffuser plate 26. A plurality of light scattering microstructures 56 are disposed along the upper surface 52 of the anti-glare plate 28. Specifically, the plurality of light scattering microstructures 56 are disposed along a surface (i.e., the upper surface 52) of the anti-glare plate 28 and are oriented to face away from the visible light generated by the plurality of LEDs 20.
The plurality of light scattering microstructures 56 are nano-sized. The plurality of light scattering microstructures 56 each include a substantially rounded or semi-circular profile. Although a rounded profile is illustrated in
Referring generally to the figures, the disclosed edge-lit reading lamp offer various technical effects and benefits. Specifically, in one embodiment, the entire height of the housing containing the LEDs of the edge-lit reading lamp is about four millimeters. In contrast, some conventional reading lamps include a height of about fourteen millimeters. Therefore, the disclosed reading lamp requires significantly less space and is much easier to package. Furthermore, the disclosed reading lamp also provides high quality visible light having a satisfactory UGR value (19 or less) and a decreased amount of blue light when compared to conventional reading lamps. Some conventional reading lamps may not produce visible light having a satisfactory UGR value. Furthermore, the visible light produced by conventional reading lamps may also include significant amounts of visible blue light, which may cause digital eye strain.
The description of the present disclosure is merely exemplary in nature and variations that do not depart from the gist of the present disclosure are intended to be within the scope of the present disclosure. Such variations are not to be regarded as a departure from the spirit and scope of the present disclosure.
