Vehicle lighting equipment

Abstract

To secure excellent visibility all day and all night.SOLUTION: An on-vehicle lighting system comprises: a first light source that emits first visible light whose main wavelength is a first wavelength toward a predetermined place; a second light source that emits second visible light whose main wavelength is a second wavelength shorter than the first wavelength toward the predetermined place; and a light source control part that selects, as a light source for lighting the predetermined place, the first light source when lightness of the predetermined place is bright and the second light source when lightness of the place is dark.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The present invention relates to an in-vehicle lighting device mounted on a vehicle. [Background technology]

[0002] Conventionally, an on-vehicle lighting device mounted on a vehicle has been known (for example, Patent Document 1). The on-vehicle lighting device includes a light source that emits visible light toward a predetermined location. Examples of the on-vehicle lighting device include a welcome lamp and an illumination lamp. The light source is installed on the exterior or interior of the vehicle, and is arranged on the rear side of the bumper or grill at the front or rear of the vehicle. The light source is generally configured to emit visible light in a wavelength range (for example, 480 nm to 580 nm) that is highly visible to humans, particularly during the daytime, within the visible light range (for example, 360 nm to 830 nm). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-13722 Summary of the Invention [Problem to be solved by the invention]

[0004] The luminosity factor, which is the degree of brightness perceived by the human eye, changes between photopic vision during the day and scotopic vision at night. However, if a single light source is used and the dominant wavelength of the visible light emitted by that light source is simply set to match daytime visibility, then even if excellent daytime visibility is ensured, nighttime visibility will be reduced.

[0005] The present invention has been made in view of the above points, and has an object to provide an in-vehicle lighting device that has excellent visibility both day and night. [Means for solving the problem]

[0006] One aspect of the present invention is an in-vehicle lighting device including a first light source that emits first visible light having a dominant wavelength of a first wavelength toward a predetermined location; a second light source that emits second visible light having a dominant wavelength of a second wavelength that is shorter than the first wavelength toward the predetermined location; and a light source control unit that sets an irradiation light source that illuminates the predetermined location to the first light source when the predetermined location is located in a bright environment, and to the second light source when the predetermined location is located in a dark environment.

[0007] This configuration ensures excellent visibility day and night. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a diagram illustrating a vehicle equipped with an in-vehicle lighting device according to an embodiment of the present invention. [Figure 2] 2 is a diagram showing a location to be irradiated with visible light emitted from the vehicle-mounted lighting device according to the embodiment; FIG. [Figure 3] 1 is a configuration diagram of an in-vehicle lighting device according to an embodiment; [Figure 4] 3 is a diagram illustrating a schematic view of the emission range of visible light from a first light source and a second light source included in the in-vehicle lighting device according to the embodiment; FIG. [Figure 5] FIG. 1 is a diagram showing the relationship between wavelength and photopic luminosity (solid line) and the relationship between wavelength and scotopic luminosity (dashed line). [Figure 6] 1 is a diagram showing the relationship between the wavelength and radiant flux of a first light source (dashed line) and the relationship between the wavelength and radiant flux of a second light source (dashed line). [Figure 7] 7 is a diagram in which the relationship shown in FIG. 5 and the relationship shown in FIG. 6 are superimposed. [Figure 8] 4 is a flowchart illustrating an example of a control routine executed by a light source control unit in the in-vehicle lighting device according to the embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Specific embodiments of the in-vehicle lighting device according to the present invention will be described below with reference to FIGS.

[0010] An in-vehicle lighting device 1 according to one embodiment is a lighting device mounted on a vehicle. The in-vehicle lighting device 1 illuminates a road surface outside the vehicle, the exterior of the vehicle, or a specific location inside the vehicle cabin with visible light. The in-vehicle lighting device 1 can make the location illuminated with visible light more easily visible to people. The in-vehicle lighting device 1 is installed on a bumper, grille, or back door attached to the front or rear of the vehicle, or on the ceiling of the vehicle cabin. In FIG. 1, the in-vehicle lighting device 1 is installed on the rear of the vehicle, and emits visible light toward the outside of the vehicle.

[0011] The in-vehicle lighting device 1 includes a primary light source 10 and a secondary light source 20. The primary light source 10 and the secondary light source 20 are each a light source that emits visible light (for example, in the visible light region with wavelengths of 360 nm to 830 nm). The primary light source 10 and the secondary light source 20 each emit the visible light toward a common predetermined location S (shown as locations S1 and S2 in FIGS. 1 and 2) as shown in FIG.

[0012] The lighting conditions under which the first light source 10 and the second light source 20 emit visible light may be any predetermined condition, such as when a user approaches the vehicle from outside while the vehicle is stopped or stopped, when a vehicle door is opened, or when a predetermined operation required for lighting is performed.

[0013] The areas to be illuminated, where the first light source 10 and the second light source 20 emit visible light, are located on the road surface outside the vehicle, on the exterior surface of the vehicle, or inside the vehicle cabin. The area S where the first light source 10 emits visible light and the area where the second light source 20 emits visible light overlap each other in area area and are located at the same position relative to the vehicle. The area of ​​the area to be illuminated may be a shape representing letters, pictures, signs, etc., or a simple geometric shape.

[0014] The primary light source 10 and the secondary light source 20 may be mounted on the same substrate 30 as shown in Fig. 3, or may be mounted on separate substrates. Furthermore, the primary light source 10 and the secondary light source 20 are preferably disposed close to each other, but may also be disposed at positions separated from each other. The primary light source 10 and the secondary light source 20 may, for example, be attached to a lamp housing to form a lamp assembly, and may be fixed to the vehicle body via a bracket or the like by screwing or claw fitting.

[0015] The primary light source 10 and the secondary light source 20 are each light emitters such as LEDs made of semiconductor elements. The primary light source 10 and the secondary light source 20 each emit light when a predetermined voltage is applied. The primary light source 10 and the secondary light source 20 are connected to a light source control unit 40 (described below), and their light emission is controlled by the light source control unit 40.

[0016] As shown in Fig. 5, luminosity, which is the degree of brightness perceived by the human eye, varies between daytime (photopic vision) and nighttime (scotopic vision) (see JIS Z 8785:2019). Specifically, the luminosity perceived by humans during the day (photopic luminosity) has a peak at a wavelength near 555 nm as shown by the solid line in Fig. 5, while the luminosity perceived by humans at night (scotopic luminosity) has a peak at a wavelength near 507 nm, which is shorter than the photopic luminosity, as shown by the dashed line in Fig. 5. For this reason, if a single light source is used as the in-vehicle lighting device 1, there is a risk that either daytime visibility or nighttime visibility will be impaired.

[0017] Therefore, the first light source 10 and the second light source 20 are set as follows in accordance with the photopic luminosity and the scotopic luminosity: Note that daytime may mean that the illuminance exceeds a predetermined lux (for example, 1000 [lx]), and nighttime may mean that the illuminance is equal to or lower than the predetermined lux.

[0018] The primary light source 10 is a light source that has excellent visibility to humans in the daytime. The visible light emitted by the primary light source 10 (hereinafter referred to as first visible light) has an emission spectrum, for example, as shown by the dashed line in FIG. 6. The dominant wavelength of the first visible light is in the range of 531 nm to 580 nm, for example, 550 nm, in accordance with photopic luminosity. The secondary light source 20 is a light source that has excellent visibility to humans at night. The visible light emitted by the secondary light source 20 (hereinafter referred to as second visible light) has an emission spectrum, for example, as shown by the dashed two-dot line in FIG. 6. The dominant wavelength of the second visible light is shorter than that of the first visible light and is in the range of 480 nm to 531 nm, for example, 520 nm, in accordance with scotopic luminosity.

[0019] Luminous flux is a physical quantity that represents the degree of human visual perception, and is expressed in lumens [lm]. Luminous flux is a weighted value Φ for each wavelength, and is expressed by the following equation (1) using the radiant flux P(λ) and luminosity factor K(λ) for each wavelength. Φ=∫(K(λ)×P(λ))dλ ···(1)

[0020] As mentioned above, the luminous efficiency K(λ) varies between the daytime (photopic vision) and the nighttime (scotopic vision), and there are two types: the photopic luminous efficiency K(λ) corresponding to the daytime, and the scotopic luminous efficiency K'(λ) corresponding to the nighttime. The emission spectrum of the first light source 10, i.e., the radiant flux P1(λ) for each wavelength, is shown by the dashed-dotted line in Fig. 6. The emission spectrum of the second light source 20, i.e., the radiant flux P2(λ) for each wavelength, is shown by the dashed-two-dotted line in Fig. 6.

[0021] The first light source 10 and the second light source 20 satisfy the following relationships for photopic vision and scotopic vision. Specifically, in photopic vision, the luminous flux Φ1 of the first visible light from the first light source 10 based on the photopic luminous efficiency K(λ) (hereinafter referred to as the photopic luminous flux Φ1) is higher than the luminous flux Φ2 of the second visible light from the second light source 20 based on the photopic luminous efficiency K(λ) (hereinafter referred to as the photopic luminous flux Φ2) (see the following formula (2)). In addition, in scotopic vision, the luminous flux Φ1' of the first visible light from the first light source 10 based on the scotopic luminous efficiency K'(λ) (hereinafter referred to as the scotopic luminous flux Φ1') is lower than the luminous flux Φ2' of the second visible light from the second light source 20 based on the scotopic luminous efficiency K'(λ) (hereinafter referred to as the photopic luminous flux Φ2') (see the following formula (3)). Φ1>Φ2 (2) Φ1´<Φ2´ (3)

[0022] Note that a plurality of primary light sources 10 and a plurality of secondary light sources 20 may be provided in accordance with the size (area) of the location S to be illuminated with visible light and the distance to the location S. In this case, for example, a plurality of sets each consisting of one primary light source 10 and one secondary light source 20 may be arranged side by side in a predetermined direction, or a plurality of primary light sources 10 may be grouped together and a plurality of secondary light sources 20 may be grouped together, and the group of primary light sources 10 and the group of secondary light sources 20 may be arranged adjacent to each other.

[0023] The in-vehicle lighting device 1 may also include lenses that refract the first visible light emitted by the primary light source 10 and the second visible light emitted by the secondary light source 20. These lenses may be provided separately as a lens corresponding to the primary light source 10 and a lens corresponding to the secondary light source 20, or the lenses corresponding to the primary light source 10 and the secondary light source 20 may be integrated into one lens.

[0024] The in-vehicle lighting device 1 includes a light source control unit 40. The light source control unit 40 is a component that controls the turning on and off of the first light source 10 and the second light source 20. The light source control unit 40 is mainly composed of a microcomputer. The light source control unit 40 is housed in a housing, for example, and disposed at the rear of the vehicle body. The light source control unit 40 operates by receiving power from a power source such as an in-vehicle battery.

[0025] The light source control unit 40 is capable of determining the lighting conditions and extinguishing conditions of the first light source 10 and the second light source 20, and is also capable of switching the illumination light source between the first light source 10 and the second light source 20 depending on the brightness at which a predetermined location S from which the first light source 10 and the second light source 20 emit visible light is located.

[0026] The in-vehicle lighting device 1 includes a sensor unit 50. The sensor unit 50 is an illuminance sensor that detects the brightness at the location of the predetermined position S. The sensor unit 50 is configured, for example, by combining a photodiode and a transistor. The sensor unit 50 is disposed so as to be exposed from the vehicle body, and is disposed, for example, in the vicinity of the primary light source 10 and the secondary light source 20. The sensor unit 50 may be a dedicated component for the in-vehicle lighting device 1, or may be a multi-purpose component that can also be used for other devices (for example, a device that automatically turns on and off vehicle headlamps).

[0027] Next, the operation of the in-vehicle lighting device 1 will be described. In the in-vehicle lighting device 1, the light source control unit 40 operates according to the flowchart shown in Fig. 8. First, the light source control unit 40 determines whether or not the lighting conditions for the first light source 10 and the second light source 20 are met (step S100). These lighting conditions include, for example, that the user has approached the vehicle from outside the vehicle, that the vehicle door has been opened, or that a predetermined operation required for lighting has been performed. If the light source control unit 40 determines that the lighting conditions are not met, it ends the processing without proceeding with the rest of the routine.

[0028] On the other hand, if the light source control unit 40 determines that the above lighting conditions are met, it then detects brightness using the sensor unit 50 (step S110). Then, it determines whether the detected brightness exceeds a predetermined lux, that is, whether it is currently daytime (step S120). Note that this predetermined lux may be any illuminance that distinguishes daytime from nighttime, and is set to, for example, 1000 [lx].

[0029] If light source control unit 40 determines that the brightness exceeds the predetermined lux and that it is currently daytime, it sets primary light source 10 as the irradiation light source that illuminates predetermined location S and causes primary light source 10 to emit first visible light (step S130). In this case, primary light source 10 is turned on, and therefore predetermined location S is illuminated with the first visible light.

[0030] On the other hand, if the brightness is equal to or lower than the predetermined lux and it is determined that it is currently nighttime, light source control unit 40 sets second light source 20 as the irradiation light source that illuminates the predetermined location and causes second light source 20 to emit second visible light (step S140). In this case, second light source 20 is turned on, and therefore predetermined location S is illuminated with the second visible light.

[0031] In this way, in the in-vehicle lighting device 1, the irradiation light source that illuminates the predetermined location S can be switched between the first light source 10 and the second light source 20 depending on the brightness at which the predetermined location S is located. Specifically, the irradiation light source can be the first light source 10 when the brightness is brighter than a predetermined lux, and can be the second light source 20 when the brightness is darker than the predetermined lux.

[0032] Photopic luminosity and scotopic luminosity are different from each other. Specifically, photopic luminosity has a peak at a longer wavelength than scotopic luminosity, and scotopic luminosity has a peak at a shorter wavelength than photopic luminosity. The first light source 10 is a light source that is highly visible to humans in the daytime, and the second light source 20 is a light source that is highly visible to humans at night. The dominant wavelength of the second visible light emitted by the second light source 20 is shorter than the dominant wavelength of the first visible light emitted by the first light source 10.

[0033] Therefore, the in-vehicle lighting device 1 can illuminate the predetermined location S with the first visible light from the primary light source 10 or the second visible light from the secondary light source 20 in accordance with the brightness at which the predetermined location S is located (specifically, the brightness when the primary light source 10 and the secondary light source 20 are not lit). Specifically, the predetermined location S can be illuminated with the first visible light on the longer wavelength side when the brightness is bright, and with the second visible light on the shorter wavelength side when the brightness is dark. Therefore, the in-vehicle lighting device 1 can ensure excellent visibility both day and night, rather than ensuring visibility only during either daytime or nighttime.

[0034] Furthermore, in the in-vehicle lighting device 1, when the predetermined location S is bright, the first light source 10 is used as the irradiation light source, whereas when the predetermined location S is dark, the second light source 20 is used as the irradiation light source. In this configuration, when the predetermined location S is bright, the second light source 20 is not activated and does not emit the second visible light. Furthermore, when the predetermined location S is dark, the first light source 10 is not activated and does not emit the first visible light.

[0035] During the day, even if the secondary light source 20 is not turned on, the wavelength peak of the secondary light source 20 deviates from the photopic luminosity, so there is no impact on people's visibility of the predetermined location S during the day. Furthermore, at night, even if the primary light source 10 is not turned on, the wavelength peak of the primary light source 10 deviates from the scotopic luminosity, so there is no impact on people's visibility of the predetermined location S during the night. Therefore, the predetermined location S can be illuminated with visible light without turning on unnecessary light sources 10, 20, so efficient lighting can be achieved without consuming excessive power.

[0036] In the above embodiment, the dedicated sensor unit 50 detects the brightness at which the predetermined location S is placed, and the light source control unit 40 switches the illumination light source between the first light source 10 and the second light source 20 based on the detection result of the sensor unit 50. However, the present invention is not limited to this, and the light source control unit 40 may detect an operation or state that depends on the brightness as the brightness at which the predetermined location S is placed, and switch the illumination light source between the first light source 10 and the second light source 20 in conjunction with the operation or state.

[0037] The above-mentioned operation or state depending on brightness may be, for example, the turning on and off of vehicle headlamps that are turned off during the day and turned on at night. In this case, the switching of the irradiation light source between the primary light source 10 and the secondary light source 20 is performed in conjunction with the turning on and off of the vehicle headlamps. According to the configuration of this modified embodiment, it is not necessary to use a dedicated sensor unit 50 to switch the irradiation light source between the primary light source 10 and the secondary light source 20, and therefore the configuration of the in-vehicle lighting device 1 can be simplified.

[0038] In the above embodiment, the illumination light source is switched between the first light source 10 and the second light source 20 in a binary manner, i.e., either the first light source 10 or the second light source 20 is set as an illumination light source at 100% and the other is set as an illumination light source at 0%. However, the present invention is not limited to this, and the constituent ratio of the illumination light source may be switched between the first light source 10 and the second light source 20. For example, the constituent ratio of the illumination light source may be set such that when the brightness at the predetermined location S is bright, the first light source 10 is set at 75% and the second light source 20 is set at 25%, and when the brightness is dark, the first light source 10 is set at 25% and the second light source 20 is set at 75%.

[0039] Furthermore, in the above modified embodiment, the brightness at which the specified location S is located may be detected in multiple stages, and the composition ratio of the illumination light source may be changed in multiple stages or linearly according to that brightness.

[0040] The present invention is not limited to the above-described embodiments and modifications, and various modifications can be made without departing from the spirit of the present invention. Furthermore, this specification not only discloses the technical ideas indicated by the citation relationships set forth in the claims at the time of filing, but also discloses technical ideas obtained by appropriately combining the matters set forth in the claims. [Explanation of symbols]

[0041] 1: vehicle-mounted lighting device, 10: first light source, 20: second light source, 30: substrate, 40: light source control unit, 50: sensor unit.

Claims

1. A first light source that emits first visible light having one peak in the visible light region toward a predetermined location; a second light source that emits second visible light toward the predetermined location, the second visible light having one peak in a visible light region and a dominant wavelength shorter than that of the first visible light; a light source control unit that sets the illumination light source that illuminates the predetermined location to the first light source when the brightness of the area where the predetermined location is located is bright, and to the second light source when the brightness is dark; An in-vehicle lighting device comprising:

2. The first light source emits the first visible light so as to irradiate an image consisting of a character, a figure, a symbol, or a combination thereof; The in-vehicle lighting device according to claim 1 , wherein the second light source emits the second visible light so as to irradiate the same image as the image at the same position.

3. a sensor unit that detects the brightness, The in-vehicle lighting device according to claim 1 , wherein the light source control unit switches the illumination light source between the first light source and the second light source in accordance with the brightness detected by the sensor unit.

4. The in-vehicle lighting device according to claim 1 , wherein the light source control unit switches the illumination light source between the first light source and the second light source in conjunction with turning on and off of a vehicle headlamp depending on the brightness.

5. 5. The in-vehicle lighting device according to claim 1, wherein the first light source and the second light source satisfy a relationship in which a photopic luminous flux of the first visible light based on a photopic luminous efficiency is higher than a photopic luminous flux of the second visible light based on the photopic luminous efficiency, and a scotopic luminous flux of the first visible light based on a scotopic luminous efficiency is lower than a scotopic luminous flux of the second visible light based on the scotopic luminous efficiency.

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