WO2012090111A1

WO2012090111A1 - Generating light in a vehicle

Info

Publication number: WO2012090111A1
Application number: PCT/IB2011/055761
Authority: WO
Inventors: Sheng Peng; Di LOU; Shitao Deng
Original assignee: Koninklijke Philips Electronics N.V.
Priority date: 2010-12-31
Filing date: 2011-12-19
Publication date: 2012-07-05
Also published as: TW201233573A

Abstract

The present invention relates to a light generating device used in a vehicle. In an embodiment of the present invention, a light generating device (10) comprises a light source (11) configured to emit blue light,and a light guide unit (12) configured to direct the blue light at a preset angle with respect to a horizontal plane toward an area where the head of an occupant of the vehicle rests. With the proposed light generating device, the alertness of the user can be improved. The invention also proposes a method of generating light in a vehicle.

Description

GENERATING LIGHT IN A VEHICLE

FIELD OF THE INVENTION

The invention relates to a light generating device, more specifically to a light generating device used in a vehicle. The invention also relates to a method of generating light in a vehicle.

BACKGROUND OF THE INVENTION

Eyestrain is often a problem for an occupant of a vehicle, especially the driver. Extraocular muscles which are fixated for a long time may induce eyestrain. Besides, the whole body of the occupant of the vehicle may be in a status of fatigue, so that the brain or optic nerves and other nerves that control eyeball movement and form visual images become slow in terms of effectiveness and therefore result in reduced alertness.

It has been proposed to form in front of the driver of the vehicle a virtual image close to said driver and a virtual image far away from said driver, so that the driver may look from short distance to long distance and such adjustment of extraocular muscles may relax said muscles, thereby reducing eyestrain.

However, the above method causes the driver to become distracted, and thus always brings more risks. Moreover, the method does not deal with the problem of reduced alertness resulting from fatigue. SUMMARY OF THE INVENTION

It would be desirable to obviate or mitigate at least some of the above disadvantages and provide an improved device and method for use in a vehicle.

To better address one or more of these concerns, in a first aspect of the invention, a light generating device in a vehicle is presented. The proposed light generating device comprises a light source configured to emit blue light, and a light guide unit configured to direct the blue light, at a preset angle with respect to a horizontal plane, toward an area where the head of an occupant of the vehicle rests.

For an occupant of a vehicle, it would be advantageous in some cases to enjoy increased alertness. For the driver of the vehicle, for example, the increased alertness contributes to safe driving. Improved alertness is particularly helpful to those driving a long distance or at night, since fatigue or sleepiness in these situations may result in reduced alertness, and thus in dangerous situations.

Melatonin in the human body can affect alertness, and a low melatonin level is helpful to stay alert. Moreover, melanopsin contained in eyes is a light sensor and hence regulates or suppresses melatonin secretion.

The inventor has recognized that it is possible to improve the alertness of an occupant of a vehicle by making use of the property of melanopsin contained in eyes, and thus suppress the melatonin level in the occupant's body. In particular, the light generating device as described above directs blue light at a preset angle with respect to a horizontal plane toward an area where the head of the occupant sitting in the vehicle rests. The blue light can reach the eyes of the user and thus reduce eyestrain, and at the same time it can be sensed by melanopsin contained in the eyes of the occupant, thereby enabling the melatonin level in the occupant's body to be suppressed, which results in increased alertness.

Melanopsin is found in a central retinal region. Meanwhile, melanopsin is also expressed in peripheral retinal cones of a peripheral retinal region, which means that the peripheral retinal region can also be responsive to light to regulate or suppress melatonin secretion. The inventor has recognized that such response of the peripheral retinal region to light can be used advantageously, since compared with light falling into the central retinal region, light falling into the peripheral retinal region has less effect on a person's vision and thus will not compromise safety.

In one embodiment, the preset angle is in the range of 40 to 50 degrees measured from the horizontal plane. The selection of the preset angle in the above range allows at least a portion of the blue light to fall into the peripheral retinal region of the eyeball of the user. The light can be sensed by melanopsin in the peripheral retinal cones of the peripheral retinal region and hence the melatonin level in the occupant's body can be suppressed. Therefore, the alertness of the user can be improved while safety is not compromised or to a lesser degree.

In another embodiment, the majority of the blue light enters the peripheral retinal region of the eyeball of the user, which offers a safer solution for improving alertness.

In another embodiment, the light generating device in the vehicle may further comprise a sensor configured to sense the position of the head of the occupant relative to the position of the sensor. By using the sensor, it is possible to direct light more precisely and hence ensure that the light will fall into the eyes of the user, particularly the peripheral retinal region, for example.

In a further embodiment, the light generating device in the vehicle may further comprise a controller, which is configured to control the light generating device so as to adjust the angle of the blue light on the basis of the position sensed by the sensor.

In a further embodiment, the light intensity of the blue light is in the range of 1 to

Light with an intensity in this range is not easily noticeable by an occupant of the vehicle. More preferably, the light intensity of the blue light is in the range of 3 to

A light intensity in this range elicits significant melatonin suppression and therefore improves alertness more efficiently.

In a further embodiment, the wavelength of the blue light is in the range of 420 to

460nm. Blue light of a wavelength in this range achieves a significantly higher efficiency of melatonin suppression, and thus the required light intensity is relatively low.

In a second aspect of the invention, a method of generating light in a vehicle is proposed. The method comprises a step of emitting blue light and a step of directing the blue light, at a preset angle with respect to a horizontal plane, toward an area where the head of an occupant of the vehicle rests.

In another embodiment, the method of generating light further comprises the step of sensing the position of the head of the user. And in a further embodiment, the method of generating light further comprises the step of adjusting the angle of the blue light, on the basis of the sensed position.

In a third aspect of the invention, there is proposed a computer program. The computer program comprises a computer readable code which, when run on a processor, enables at least part of the method of generating light to be performed. The computer program may be stored on a computer-readable medium.

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

The proposed light generating device and the method of generating light in a vehicle will be described in the following by way of examples and with reference to the accompanying drawings, without limiting the scope of protection as defined by the claims. In the Figures:

Figure 1 is a schematic view of a light generating device in a vehicle according to an embodiment of the present invention;

Figure 2 shows light falling into the eyes of an occupant of a vehicle and the corresponding vision of the occupant according to an embodiment of the present invention;

Figure 3 shows an example of a light generating device in a vehicle according to an embodiment of the present invention;

Figure 4 shows another example of a light generating device in a vehicle according to an embodiment of the present invention;

Figure 5 shows an example of an optical unit according to an embodiment of the present invention;

Figure 6 schematically shows a flow chart of a method of generating light in a vehicle according to an embodiment of the present invention;

Figure 7 schematically shows a flow chart of a method of generating light in a vehicle according to another embodiment of the present invention; and

Figure 8 schematically shows a flow chart of a method of generating light in a vehicle according to a further embodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS

While the invention covers various modifications and alternative constructions, embodiments of the invention are shown in the drawings and will hereinafter be described in detail. However, it should be understood that the specific description and drawings are not intended to limit the invention to the specific forms disclosed. On the contrary, the scope of the claimed invention is intended to include all modifications and alternative constructions thereof falling within the scope of the invention as expressed in the appended claims.

Figure 1 is a schematic view of a light generating device in a vehicle according to an embodiment of the present invention.

As shown in Figure 1, the light generating device 10 comprises a light source 11 and a light guide unit 12. The light source 1 1 is configured to emit blue light. The light guide unit 12 is configured to transmit the blue light and direct the blue light, at a preset angle with respect to a horizontal plane 13, toward an area where the head of an occupant of the vehicle rests.

As described above, melatonin in the human body can affect alertness and a low melatonin level is helpful to stay alert. Moreover, melanopsin contained in eyes is a light sensor and hence regulates or suppresses melatonin secretion. The inventor has recognized that it is possible to improve the alertness of an occupant of a vehicle by making use of the property of melanopsin contained in eyes and thus suppress the melatonin level in the occupant's body.

The light generating device 10 is designed on the basis of such recognition. When it is in operation, the light source 11 emits blue light which is directed at a preset angle with respect to the horizontal plane 13 toward an area where the head of the occupant of the vehicle rests by the light guide unit 12. The blue light can reach the eyes of the user and thus reduce eyestrain; meanwhile, it can be sensed by melanopsin contained in the eyes of the user and therefore enables the melatonin level in the user's body to be suppressed, which results in increased alertness.

In another embodiment, the light guide unit 12 is further configured to guide the blue light toward the eyes of the occupant of the vehicle, which reduces the emission range of light and therefore enables the power of the light source to be reduced.

Melanopsin is found in the central retinal region, and it is also expressed in peripheral retinal cones of the peripheral retinal region, meaning that the peripheral retinal region can also be responsive to light to regulate or suppress melatonin secretion. As mentioned above, the inventor has recognized that such response of the peripheral retinal region to light can be used advantageously, since, compared with light falling into the central retinal region, light falling into the peripheral retinal region has less effect on a person's vision.

Figure 2 shows light falling into the eyes of an occupant of a vehicle and the corresponding effect on the vision of said occupant according to an embodiment of the present invention. In Figure 2, reference numbers 14, 15 and 16 indicate a peripheral retinal region, a central retinal region and an eye pupil, respectively, of the eyes of an occupant of a vehicle. As shown in Figure 2, in a peripheral view 17 formed by the eyes of the occupant, light falling into the peripheral retinal region 14 of the eyeball of the user will form a light spot 19 outside the central view area 18. Therefore, the light spot

19 formed by light falling into the peripheral retinal region 14 has a smaller effect on a person's vision and hence is not easily noticeable by the occupant. This will be advantageous in some applications. For a driver of the vehicle, for example, the light spot formed in this way will not compromise safety during driving.

Optionally, the preset angle with respect to the horizontal plane 13 may be in the range of 40 to 50 degrees. The selection of the preset angle in such a range allows at least a portion of the blue light to fall into the peripheral retinal region of the eyeball of the user. The light can be sensed by melanopsin in the peripheral retinal cones of the peripheral retinal region and hence enable the melatonin in the user's body to be suppressed. Therefore, the alertness of the user can be improved while safety is compromised less or not at all.

Optionally, the light intensity of the blue light may be in the range of 1 to

Light with an intensity in this range is not easily noticeable by the occupant of the vehicle. For a driver of the vehicle, for example, such a low light intensity is barely detectable and will not take the driver's attention off the road, thereby providing a safer solution for improving alertness. More preferably, the light intensity of the blue light is in the range of 3 to

As an example, the wavelength of the blue light may be in the range of 420 to 460nm. A wavelength in this range achieves a significantly higher melatonin suppression efficiency, and thus the required light intensity is relatively low.

Figure 3 shows an example of the light generating device in a vehicle according to an embodiment of the present invention.

In the example shown in Figure 3, the light source of the light generating device is an LED 11a, and the light guide unit is a lens 12a. Optionally, the diameter of an emitting area of the LED may be 1mm and the emission angle may be ±60°. The lens may be a Meniscus lens having a first surface and a second surface. By way of example, the first surface is a spherical surface with a radius of 70mm and the second surface is a conic surface with a radius of 9.9mm and a conic coefficient of 0.6. Optionally, the thickness of the Meniscus lens is 12mm and the outer diameter of the Meniscus lens is 24mm. The material used for the lens could be, for example, SF6_Schott, and the space between the first surface of the lens and the light source is preferably 6.74mm in this embodiment.

Figure 4 shows another example of the light generating device in a vehicle according to an embodiment of the present invention.

As shown in Figure 4, the light source in this example is an LED 1 lb, and the light guide unit is a reflector 12b. Optionally, the distance from the LED to the center of the reflector may be 5mm. By way of example, the reflective surface of the reflector has a radius of 9.0mm and a conic coefficient of 1.0, and the outer diameter of the reflector is 40mm.

It should be noted that Figures 3 and 4 illustrate only two examples of the light generating device according to an embodiment of the present invention. The light generating device according to the present invention is not limited to these examples. For instance, the light source of the light generating device is not necessarily an LED. Any light source capable of emitting blue light may be used.

In another embodiment, the light generating device in the vehicle may further comprise a sensor (not shown) configured to sense the position of the head of the user relative to the position of the sensor. For example, the sensor can sense the position of the head of the user before the light guide unit directs the blue light. Therefore, the angle with respect to the horizontal plane, at which the blue light is to be directed, can be preset based on the sensed position. By using the sensor, it is possible to direct light more precisely and hence ensure that the light will fall into the eyes of the user, particularly the peripheral retinal region, for example.

In a further embodiment, the light generating device in the vehicle may further comprise a controller (not shown), which is configured to control the light generating device so as to adjust the angle of the blue light on the basis of the position sensed by the sensor. As an example, information of the sensed position may be stored in a memory, which may be formed separately from or integrally with the sensor. When required, the controller may read the information from the memory and then control the light source or the light guide unit, based on the information, so as to adjust the angle of the blue light. The light generating device with this configuration allows the direction of the blue light to be adjusted. Such configuration of the light generating device is particularly advantageous in some cases. In practice, the head of the occupant of the vehicle is not always in a fixed position. For example, the driver of the vehicle may raise or lower his head while driving. In this case, the angle of the blue light can be adjusted, based on the sensed position, which enables the light to be redirected according to the actual position of the head of the occupant.

An occupant of a vehicle often moves his head in the horizontal direction. For example, the driver of the vehicle may turn his head while driving. In consideration of the horizontal movement of the occupant's head, the light generating device according to an embodiment of the present invention may further comprise an optical unit, which is configured to increase the horizontal beam divergence of the blue light. The optical unit ensures that the blue light reaches the eyes of the occupant under normal horizontal movement of the occupant's head.

Figure 5 shows an example of the optical unit. As shown in Figure 5, the optical unit is a microstructure lens, for example. The microstructure lens may be a semi-cylinder microstructure lens comprising a plurality of semi-cylinder microsurfaces. The semi-cylinder microstructure lens is placed properly, so that it transmits the blue light directed by the light guide unit and increases the horizontal beam divergence of the light. The semi-cylinder microsurfaces are aligned vertically, so that the blue light can be spread over a wider range in a lateral direction.

The light generating device according to an embodiment of the present invention has been described above. When used in a vehicle, the light generating device may be installed in different positions. For example, the light generating device may be installed in a panel area of the vehicle. The light generating device may also be installed on the upper side relative to the occupant. For example, it may be installed in an area close to the rearview mirror of the vehicle. In this case, the blue light will be directed downwards, but still travels at a preset angle with respect to a horizontal plane. By selecting the installation position of the light generating device and the preset angle properly, the blue light can enter into the peripheral retinal region of the eyeball of the user, which results in increased alertness of the occupant, while safety is compromised less or not at all .

While a light generating device in a vehicle has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The light generating device according to the present invention is not limited to the disclosed embodiments. The different embodiments described above can also be combined, dependent on the requirements.

Figure 6 schematically shows a flow chart of a method of generating light in a vehicle according to an embodiment of the present invention.

As shown in Figure 6, the method of generating light in a vehicle according to the embodiment comprises two steps. At step 21 , blue light is emitted; and at step 22, the blue light is directed, at a preset angle with respect to a horizontal plane, toward an area where the head of an occupant of the vehicle rests.

Optionally, step 22 of directing the blue light may comprise converging the blue light toward the eyes of the user, which reduces the emission range of light and therefore enables the power of the light source to be reduced.

Optionally, the preset angle with respect to the horizontal plane may be in the range of 40 to 50 degrees. As described above, the selection of the preset angle in such a range enables at least a portion of the blue light to fall into the peripheral retinal region of the eyeball of the user and hence offers a safe solution for increasing the alertness of the user.

Optionally, the light intensity of the blue light may be in the range of 1 to

which intensity is not easily noticeable by the occupant of the vehicle and thus will not distract the user's attention. More preferably, the light intensity of the blue light is in the range of 3 ΐοΙ ΟμλΥ/ΰΐη². A light intensity in this range elicits significant melatonin suppression and therefore improves alertness more efficiently.

Figure 7 schematically shows a flow chart of a method of generating light in a vehicle according to another embodiment of the present invention.

As shown in Figure 7, the method of generating light according to this embodiment further comprises a step 23 of sensing the position of the head of the user, in addition to steps 21 and 22. The position of the head of the user can be sensed before the blue light is directed. Therefore, the angle with respect to the horizontal plane, at which the blue light is to be directed, can be preset based on the sensed position. With this step, it is possible to direct light more precisely and hence ensure that the light will fall into the eyes of the user, particularly the peripheral retinal region, for example.

It should be noted that the sequence of performing the steps of the method of generating light is not limited to that shown in Figure 7. For example, step 23 of sensing the position may be performed before step 21 of emitting blue light.

As shown in Figure 8, the method of generating light according to this embodiment further comprises a step 24 in addition to the steps 21, 22 and 23. The method according to this embodiment can be performed as follows. At step 21, blue light is emitted; at step 22, the blue light is directed, at a preset angle with respect to a horizontal plane, toward an area where the head of an occupant of the vehicle rests; at step 23, the position of the head of the user is sensed; and at step 24, the angle of the blue light is adjusted on the basis of the sensed position. In this embodiment, the additional step 24 allows the direction of the blue light to be adjusted. As described above, such a method of generating light in a vehicle is particularly advantageous in some cases, since the head of the occupant of the vehicle is not always in a fixed position. With step 24, the angle of the blue light can be adjusted based on the sensed position, which enables the light to be redirected according to the actual position of the head of the user.

It should be understood that the sequence of performing the steps of the method of generating light is not limited to that shown in Figure 8. For example, step 23 of sensing the position may be performed before step 21 , or after the step 21 but before step 22. In some applications, the step of sensing the position or the step of adjusting the angle of the blue light may be performed periodically or non-periodically, dependent on the requirement.

Some or all of the steps of the methods as described above may alternatively be implemented by a processor in combination with e.g. a computer program. The computer program comprises a computer readable code which, when run on the processor, enables at least some steps of any of the methods described herein to be performed. The computer program may be stored on a computer-readable medium.

While the invention has been illustrated and described in detail in the drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive. The invention is not limited to the disclosed embodiments. The different embodiments described above and in the claims can also be combined. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from the study of the drawings, the disclosure and the appended claims.

In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. The reference signs in the claims should not be construed as limiting the scope of these claims.

Claims

1. A light generating device (10) in a vehicle, comprising:

- a light source (1 1), configured to emit blue light; and

- a light guide unit (12), configured to direct the blue light, at a preset angle with respect to a horizontal plane, toward an area where the head of an occupant of the vehicle rests.

2. The light generating device according to claim 1 , wherein the light guide unit (12) is further configured to converge the blue light toward the eyes of the user.

3. The light generating device according to claim 1 , wherein the preset angle is in the range of 40 to 50 degrees.

4. The light generating device according to claim 1 , wherein the light intensity of the blue light is in the range of 1 to 20μW/cm², preferably in the range of 3 tol0μW/cm².

5. The light generating device according to claim 1 , wherein the wavelength of the blue light is in the range of 420 to 460nm.

6. The light generating device according to any one of claims 1 to 5, further comprising a sensor configured to sense the position of the head of the occupant relative to the position of the sensor.

7. The light generating device according to claim 6, further comprising a controller configured to control the light generating device (10) so as to adjust the angle of the blue light on the basis of the sensed position.

8. The light generating device according to any one of claims 1 to 5, wherein the light generating device (10) is installed in a panel area of the vehicle or an area close to the rearview mirror of the vehicle.

9. A method of generating light in a vehicle, comprising:

- emitting (21) blue light; and

- directing (22) the blue light, at a preset angle with respect to a horizontal plane, toward an area where the head of an occupant of the vehicle rests.

10. The method according to claim 9, wherein the step of directing the blue light comprises converging the blue light toward the eyes of the occupant.

1 1. The method according to claim 9 or 10, wherein the preset angle is in the range of 40 to 50 degrees.

12. The method according to claim 9 or 10, wherein the light intensity of the blue light is in the range of 1 to 20μW/cm², preferably in the range of 3 tol0μW/cm².

13. The method according to claim 9 or 10, further comprising the step of sensing (23) the position of the head of the occupant.

14. The method according to claim 13, further comprising the step of adjusting (24) the angle of the blue light, on the basis of the sensed position.

15. A computer program comprising a computer readable code which, when run on a processor, enables at least part of the method according to any one of claims 9 to 14 to be performed.