Drawing device for vehicle

Abstract

A vehicular drawing device (1) mounted on a vehicle (100) is provided with: a light source unit that includes a plurality of light sources that emit light having mutually different wavelengths, and that emits drawing light (L) having a hue corresponding to the proportion of the light emitted from each of the light sources; a scanning unit that forms a drawing pattern (P) by scanning the drawing light (L) emitted from the light source unit; and a control unit that variably controls the color tone of the drawing light (L) and the drawing pattern (P) by performing lighting control on the plurality of light sources, and when the external illuminance of the irradiation range irradiated by the drawing light (L) exceeds a threshold value, the control unit turns off one light source that emits light of the longest wavelength among the plurality of light sources and performs lighting control on the other light sources.

Description

Technical Field

[0001] This invention relates to a vehicle drawing device.

[0002] This application claims priority based on Japanese Patent Application No. 2023-187657, filed on November 1, 2023, the contents of which are incorporated herein by reference. Background Technology

[0003] In recent years, laser light sources such as laser diodes (LDs) that can produce high brightness and high output light have been used to illuminate and depict surfaces such as roads while scanning the laser light emitted from the laser light source (for example, see Patent Document 1 below).

[0004] In addition, there are laser light sources composed of LD packages that include a red LD chip that emits red light, a green LD chip that emits green light, and a blue LD chip that emits blue light.

[0005] In such a laser light source, the proportions of red, green, and blue light emitted by each LD chip within the LD package can be controlled simultaneously, while the hue (emission color) of the laser obtained by synthesizing (mixing) these colored lights can be arbitrarily changed.

[0006] Existing technical documents

[0007] Patent documents

[0008] [Patent Document 1] Japanese Patent Application Publication No. 2020-122365 Summary of the Invention

[0009] The problem that the invention aims to solve

[0010] However, in bright environments such as daytime, it is necessary to increase the laser output to improve the visual recognizability of the depiction.

[0011] On the other hand, the results of the investigation on the effect of driving current on laser output show that, compared with the output of the green and blue LD chips mentioned above, the output of the red LD chip is more susceptible to temperature. As the driving current increases, the temperature of the LD chip also tends to rise, thus reducing the light extraction efficiency from the LD chip. Even if the driving current is increased, sufficient output cannot be obtained.

[0012] Therefore, in conventional drawing devices or systems, even if the output of the three laser colors—red, green, and blue—is increased simultaneously, the output of the red LD chip cannot keep up, resulting in insufficient brightness or deviation from the desired chromaticity, leading to insufficient contrast and making it difficult to improve visual recognition. Therefore, drawing is generally performed in dark environments such as at night.

[0013] The present invention provides a vehicle painting device that can improve the visual recognizability of the painting in a bright environment.

[0014] Methods for solving problems

[0015] The present invention provides the following means.

[0016] [1] A vehicle drawing device mounted on a vehicle, characterized in that the vehicle drawing device comprises: The light source unit includes multiple light sources that emit light of different wavelengths, and emits hues of depicting light corresponding to the proportions of light emitted from each light source; The scanning unit forms a drawing pattern by scanning the drawing light emitted from the light source unit; The control unit, by controlling the illumination of the plurality of light sources, can variably control the hue of the depicting light and the depicting pattern. When the illuminance outside the illumination range illuminated by the depicting light exceeds a threshold, the control unit turns off one of the multiple light sources that emits the longest wavelength light, and performs illumination control for the other light sources.

[0017] [2] The vehicle drawing device according to [1] above is characterized in that, When the external illuminance exceeds a threshold, the control unit controls the output of the other light sources to increase compared to before the threshold is exceeded.

[0018] [3] The vehicle drawing device according to [1] above is characterized in that, The light source unit includes a red light source that emits red light, a green light source that emits green light, and a blue light source that emits blue light. When the external illuminance exceeds a threshold, the control unit turns off the red light source and controls the lighting of the green and blue light sources.

[0019] [4] The vehicle drawing device according to [1] above is characterized in that, The wavelength of the light emitted by the light source is above 620nm.

[0020] [5] The vehicle drawing device according to [1] above is characterized in that, The wavelength of light emitted by the other light sources is below 565nm.

[0021] [6] The vehicle drawing device according to [5] above is characterized in that, The other light sources include at least GaN-based light-emitting elements.

[0022] [7] The vehicle drawing device according to [6] above is characterized in that, The other light sources include green light sources that emit green light and blue light sources that emit blue light. The green light source comprises GaN-based or InGaN-based light-emitting elements. The blue light source includes GaN-based light-emitting elements.

[0023] [8] The vehicle drawing device according to [1] above is characterized in that, The depiction pattern is formed by an outlined depiction pattern obtained through different colored lights or a negative-positive depiction pattern.

[0024] [9] The vehicle drawing device according to [1] above is characterized in that, The multiple light sources are laser light sources.

[0025]

[10] The vehicle drawing device according to [1] above is characterized in that, The control unit determines whether the external illuminance exceeds a threshold based on the external illuminance detected by the illuminance sensor mounted on the vehicle.

[0026]

[11] The vehicle drawing device according to [1] above is characterized in that, The control unit determines whether the external illuminance exceeds a threshold based on external illuminance information provided via a communication unit mounted on the vehicle.

[0027]

[12] The vehicle drawing device according to [1] above is characterized in that, The control unit sets a first threshold and a second threshold that is higher than the first threshold. When the external illuminance exceeds the first threshold, the depicting light is set to the first hue. When the external illuminance exceeds the second threshold, control is performed to set the drawing light to a second hue with a higher contrast than the first hue, either in hue or chroma.

[0028]

[13] The vehicle drawing device according to

[12] above is characterized in that, The depicting light for the first hue is green light, blue light, or monochromatic light obtained by mixing green and blue light. The second hue of the depicting light is green light, blue light, or monochromatic light obtained by mixing green light and blue light, which has a higher contrast in hue or chroma than the first hue of the depicting light.

[0029]

[14] The vehicle drawing device according to [1] above is characterized in that, The depicted pattern is projected onto the road surface.

[0030]

[15] The vehicle drawing device according to [1] above is characterized in that, The depicted pattern is projected onto the vehicle body.

[0031] Invention Effects

[0032] As described above, according to the present invention, a vehicle painting device is provided that can improve the visual recognizability of the painting in a bright environment. Attached Figure Description

[0033] Figure 1 This is a schematic diagram illustrating an example of road surface drawing performed by a vehicle drawing device according to one embodiment of the present invention.

[0034] Figure 2 It is a block diagram showing the structure of a vehicle drawing device.

[0035] Figure 3 This is a schematic diagram showing the structure of the light source and scanning unit of a vehicle drawing device.

[0036] Figure 4 This is a schematic diagram showing the structure of the light source section.

[0037] Figure 5 This is a flowchart illustrating road surface drawing performed by a vehicle-mounted drawing device.

[0038] Figure 6A This is a schematic diagram illustrating a drawing pattern created by a vehicle drawing device.

[0039] Figure 6B This is a schematic diagram illustrating a drawing pattern created by a vehicle drawing device.

[0040] Figure 6C This is a schematic diagram illustrating a drawing pattern created by a vehicle drawing device.

[0041] Figure 7 This is a flowchart illustrating an application example of road surface mapping performed by a vehicle mapping device. Detailed Implementation

[0042] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0043] Furthermore, in the accompanying drawings used in the following description, the scale of the dimensions is sometimes different depending on the component to facilitate observation of each component, and the size ratios of each component are not necessarily the same as the actual dimensions.

[0044] As one embodiment of the present invention, for example, Figures 1-7 The vehicle shown is illustrated using drawing device 1.

[0045] also, Figure 1 This is a schematic diagram illustrating an example of road surface depiction performed by a vehicle-mounted depiction device 1. Figure 2 This is a block diagram showing the structure of the vehicle drawing device 1. Figure 3 This is a schematic diagram showing the structure of the light source unit 2 and the scanning unit 3 of the vehicle drawing device 1. Figure 4 This is a schematic diagram showing the structure of the light source unit 2. Figure 5 This is a flowchart illustrating the road surface depiction performed by the vehicle-mounted drawing device 1. Figure 6A This is a schematic diagram illustrating a drawing pattern P drawn by a drawing device 1 for a vehicle. Figure 6B This is a schematic diagram illustrating a drawing pattern P drawn by a drawing device 1 for a vehicle. Figure 6C This is a schematic diagram illustrating a drawing pattern P drawn by a drawing device 1 for a vehicle. Figure 7 This is a flowchart illustrating an application example of road surface depiction by a vehicle-mounted depiction device 1.

[0046] The vehicle drawing device 1 of this embodiment is, for example, such as Figure 1 As shown, the rearview mirror 101 installed on the door of the vehicle 100 projects a road surface pattern P, such as text or images, onto the road surface T when the vehicle is stopped by a drawing light L that shines toward the road surface T on the side of the vehicle.

[0047] Furthermore, in this embodiment, the text "Welcome" to passenger H is displayed as a depiction pattern P.

[0048] Specifically, such as Figure 2 as well as Figure 3 As shown, the vehicle drawing device 1 includes a light source unit 2, a scanning unit 3, and a control unit 4 electrically connected to the light source unit 2 and the scanning unit 3.

[0049] like Figure 4 As shown, the light source unit 2 includes multiple (three in this embodiment) light sources 5R, 5G, and 5B that emit light of different wavelengths, and emits a hue (emission color) of drawing light L that corresponds to the proportion of light emitted from each of the light sources 5R, 5G, and 5B.

[0050] The light source unit 2 in this embodiment is composed of an LD package, which includes: a red LD chip (red light source) 5R that emits red light RL; a green LD chip (green light source) 5G that emits green light GL; a blue LD chip (blue light source) 5B that emits blue light BL; a first dichroic mirror 6B that reflects blue light BL; a second dichroic mirror 6G that reflects green light GL and transmits blue light BL; a third dichroic mirror 6R that reflects both blue light BL and green light GL and transmits red light RL; a first condenser lens 7R that focuses red light RL; a second condenser lens 7G that focuses green light GL; and a third condenser lens 7B that focuses blue light BL.

[0051] In addition, Figure 4 For convenience, the diagram shows the state in which the optical axes of the synthesized colors in the red light RL, green light GL, and blue light BL are offset. However, in reality, the design is such that the optical axes of the synthesized colors are aligned, and the light is ultimately incident on the MEMS mirror 3.

[0052] That is, in the light source unit 2 of this embodiment, the optical axis of the blue light BL emitted from the blue light source 5B and reflected by the first dichroic mirror 6B is aligned with the optical axis of the green light GL emitted from the green light source 5G and reflected by the second dichroic mirror 6G. Furthermore, the optical axis of the red light RL emitted from the red light source 5R and transmitted through the third dichroic mirror 6R is aligned with the optical axes of the blue light BL and the green light GL reflected by the third dichroic mirror 6R.

[0053] Thus, the three colored lights RL, BL, and GL are synthesized with their optical axes aligned, so they are incident on MEMS mirror 3 at the same incident angle and reflected by MEMS mirror 3 at the same reflection angle, and are scanned as a single drawing light L.

[0054] Furthermore, in the light source unit 2, the hue (emission color) of the drawing light L obtained by controlling the proportions of red light RL, green light GL, and blue light BL can be arbitrarily changed through the synthesis (color mixing) of these colored lights RL, GL, BL or the combination (color mixing) of these colored lights RL, GL, BL.

[0055] like Figure 3 As shown, the scanning unit 3 is composed of a MEMS (Micro-Electro-Mechanical Systems) mirror (hereinafter referred to as "MEMS mirror 3").

[0056] Specifically, the MEMS mirror 3 has: a reflector portion 31 that reflects at least the drawing light L emitted from the light source portion 2; two torsion bars (not shown) that are twisted by the vibration of piezoelectric elements formed on both sides of the reflector portion 31; a corrugated bend portion 32 that moves by the vibration of the piezoelectric elements; and an outer frame 34 that supports the bend portion 32.

[0057] In addition, Figure 3 In the MEMS mirror 3, mutually orthogonal central axes AX and AY are set. The direction of swinging with one central axis AX as the center is set as the AY direction, and the direction of swinging with the other central axis AY as the center is set as the AX direction.

[0058] The mirror section 31 is oscillating in the AY direction via a torsion bar that connects the mirror section 31 to the inner frame 33 in the AX direction. As a result, the drawing light L reflected by the mirror section 31 scans in a direction that is approximately parallel to the AX direction.

[0059] On the other hand, the mirror section 31 oscillates in the AX direction via the bending section 32. As a result, the drawing light L reflected by the mirror section 31 scans in a direction that is approximately parallel to the AX direction.

[0060] Therefore, in the MEMS mirror 3, while the reflector 31 is oscillating in a two-dimensional direction within its surface, the drawing light L reflected by the reflector 31 is scanned in two dimensions. As a result, within the illumination range E of the irradiated drawing light L on the road surface T, the road surface drawing pattern P can be drawn.

[0061] like Figure 2 As shown, the control unit 4 is composed of a microcomputer such as a CPU, and controls the amount of light and the grayscale of the depicting light L by controlling the illumination of multiple light sources 5R, 5G, and 5B (light source unit 2). In addition, the control unit 4 can variably control the depicting pattern P by driving the MEMS mirror 3.

[0062] In the vehicle drawing device 1 of this embodiment, which has the structure described above, such as Figure 1 As shown, while scanning the drawing light L emitted from the light source unit 2 through the MEMS mirror 3, the drawing light L is also irradiated from the rearview mirror 101 of the vehicle door toward the road surface T on the side of the vehicle. Thus, within the irradiation range E of the irradiated drawing light L, road surface drawing, for example, projecting text, images, or other drawing patterns P, can be performed.

[0063] However, in bright environments such as daytime, in order to improve the visual recognizability of the drawn pattern P, it is necessary to increase the output of the drawing light L emitted from the light source unit 2.

[0064] Here, the results of the investigation on the effect of driving current on laser output show that, when the output of the drawing light L is increased, compared with the output of the green light source 5G and the blue light source 5B mentioned above, the output of the red light source 5R is more susceptible to temperature. With the increase of driving current, the temperature of the LD chip (junction temperature: Tj) also increases, and the light extraction efficiency from the LD chip decreases. Even if the driving current is increased, sufficient output cannot be obtained.

[0065] Therefore, in the vehicle drawing device 1 of this embodiment, when the illuminance outside the irradiation range E of the irradiated drawing light L exceeds a threshold, one of the multiple light sources 5R, 5G, and 5B that emits the longest wavelength light (red light source 5R in this embodiment) is turned off, and the other light sources (green light source 5G and blue light source 5B in this embodiment) are controlled to be lit.

[0066] In this embodiment, one light source is a red light source 5R that emits red light RL with a wavelength of 620 nm or more and 780 nm or less, but light-emitting elements such as LDs and LEDs that emit light with a wavelength of 620 nm or more can be used. In addition, as the red light source 5R, GaAs-based light-emitting elements such as AlGaAs can be used, for example.

[0067] On the other hand, unlike the red light source 5R, the green light source 5G and the blue light source 5B, which are other light sources, do not have a reduced light extraction efficiency from the LD chip even if the temperature of the LD chip increases with the increase of the driving current. Therefore, the light output can be increased with the increase of the driving current.

[0068] 5G green light sources can use light-emitting elements such as LDs and LEDs that emit green light with wavelengths between 500nm and 565nm. Additionally, GaN-based or InGaN-based light-emitting elements can be used as green light sources in 5G.

[0069] If it is a GaN-based or InGaN-based LD chip, even if the temperature of the LD chip rises due to increasing the driving current, the decrease in luminous efficiency can be suppressed, thus improving the light output.

[0070] The blue light source 5B can use light-emitting elements such as LDs and LEDs that emit blue light (BL) with a wavelength of 450 nm or more and less than 500 nm. Furthermore, GaN-based light-emitting elements can be used as the blue light source 5B, for example.

[0071] If it is a GaN-based LD chip, even if the temperature of the LD chip rises due to increasing the driving current, the decrease in luminous efficiency can be suppressed, thus improving the light output.

[0072] In the vehicle drawing device 1 of this embodiment, in the aforementioned bright environment, the red light RL is not used; instead, the road surface is drawn using the drawing light L obtained from the green light GL and the blue light BL. This improves the contrast of the drawing light L in bright environments and enhances the visual recognizability of the drawn pattern P.

[0073] Specifically, in order to perform the aforementioned lighting control, such as Figure 2 As shown, the control unit 4 is electrically connected to the illuminance sensor 50 mounted on the vehicle 100.

[0074] As the illuminance sensor 50, a phototransistor or photodiode can be used, for example. The illuminance sensor 50 detects the external illuminance (brightness) outside the vehicle and provides the detected signal to the control unit 4. The illuminance sensor 50 processes the illuminance value, so a threshold can be freely set, and multiple thresholds can be set.

[0075] Based on the external illuminance detected by the illuminance sensor 50, the control unit 4 determines whether the external illuminance of the illumination range E illuminated by the drawing light L exceeds a threshold. The threshold is set to the value of external illuminance at which sufficient output cannot be obtained even if the driving current of the aforementioned light source (red light source 5R) is increased.

[0076] In this embodiment, based on the relationship between the light output of a light source and the ambient illuminance, a threshold value is set for the ambient illuminance at which the light output of a light source does not contribute to the brightness of the road surface. Regarding the threshold, for example, the threshold value could also be the ambient illuminance at which the driving current or light output of a light source is difficult to increase (saturation) due to the influence of heat. Furthermore, the threshold value could also be the ambient brightness of the surrounding environment where insufficient light source output is anticipated, i.e., the ambient illuminance under streetlights, on cloudy days, or on sunny days. (Under streetlights: 3,000 Lux; Cloudy day: 30,000 Lux; Sunny day: 70,000 Lux)

[0077] In addition, in the control unit 4, when the illuminance outside the irradiation range E of the illuminated drawing light L exceeds a threshold, the output of other light sources (green light source 5G and blue light source 5B) is increased compared with before the threshold is exceeded.

[0078] Furthermore, the illuminance sensor 50 is not necessarily limited to a structure mounted on the vehicle 100; for example, it could also be a structure mounted on the vehicle drawing device 1.

[0079] Alternatively, in the vehicle drawing device 1 of this embodiment, it may be configured to replace the illuminance sensor 50 described above, and determine whether the external illuminance of the irradiated range E of the irradiated drawing light L exceeds a threshold based on external illuminance information provided via the communication unit mounted on the vehicle 100.

[0080] Regarding external illuminance information, for example, it is possible to determine whether the external illuminance exceeds a threshold based on the location information of vehicle 100 and the weather information at that location.

[0081] In the vehicle drawing device 1 of this embodiment having the structure described above, for example according to Figure 5 The flowchart shown above illustrates the road surface depiction.

[0082] Specifically, firstly, such as Figure 5 As shown in step S101, the system detects whether the key owner (passenger H) has unlocked the vehicle 100 or whether someone has approached the vehicle 100.

[0083] Next, as Figure 5 As shown in step S102, the power supply of the illuminance sensor 50 and the human body sensor (not shown) corresponding to the sensing is turned on, and sensing begins.

[0084] As a human body sensing sensor, one can use an optical sensor such as an infrared sensor that uses infrared (IR) to detect the heat emitted by the human body or reflected light to detect human movement (e.g., a thermoelectric IR sensor, an infrared reflective sensor that combines an infrared LED and a photodiode).

[0085] Furthermore, as a human body sensor, any acoustic wave sensor, such as a sonar sensor, can be used to detect human movement by transmitting ultrasonic waves that collide with the person and receiving the reflected waves. The human body sensor detects the passenger H by generating a reaction within the detection range E surrounding the illumination range L of the depicting light, and outputs the detection signal to the control unit 4.

[0086] Furthermore, the human body sensor can react not only to passengers H, but also to pedestrians, animals, bicycles, motorcycles, etc. In the vehicle mapping device 1, when the human body sensor reacts, the output of the mapping light L can be stopped, thus halting the road mapping.

[0087] Additionally, as another sensing function, the power supply to the driver detection unit (not shown), which is capable of detecting the presence of passenger H within the vehicle 100, is activated.

[0088] The driver detection unit can also perform detection using any one or more of the following: door contact sensors that detect the opening and closing of the driver's side door, engine start sensors that detect engine start, and sensors (thermal sensing, pressure sensing, etc.) that detect the passenger H sitting in the driver's seat.

[0089] Next, as Figure 5As shown in step S103, in the control unit 4, the driving of MEMS mirror 3 is started (turned on), and the scanning of MEMS mirror 3 is started when each light source 5R, 5G, and 5B is turned off (turned off).

[0090] Furthermore, the MEMS mirror 3 is activated in advance because the illumination preparation takes time, but if it is activated instantaneously, it can also be done in conjunction with the following. Figure 5 The steps S106 and S108 are started together and omitted. Figure 5 Step S103.

[0091] Next, in control unit 4, such as Figure 5 As shown in step S104, a determination is made as to whether the external illuminance exceeds the threshold.

[0092] In this embodiment, the threshold is set based on external illuminance, but it can also be set based on the driving current or light output of the red light source 5R. In this case, the driving current can be read from the driving circuit of the red light source 5R. Regarding the light output, a portion of the red light RL from the red light source 5R is received using a photodiode, and its voltage value is read. Furthermore, the value of external illuminance when the driving current or light output of the red light source 5R is difficult to increase (saturation) can be set as the threshold, and it can be determined whether this threshold has been exceeded.

[0093] If the external illuminance is determined to exceed the threshold (yes), proceed to... Figure 5 In step S105, in the control unit 4, the red light source 5R is kept off (closed), and the lighting control (opening) of the green light source 5G and the blue light source 5B is performed.

[0094] At this point, for the light output of the green light source 5G and the blue light source 5B, the drive current is increased compared to when the external illuminance is below the threshold, thereby increasing the light output. Furthermore, the drive current can be controlled to be further increased according to the magnitude of the external illuminance.

[0095] Then, as Figure 5 As shown in step S106, road surface drawing is started by driving the MEMS mirror 3 using the drawing light L obtained by the green light GL and the blue light BL.

[0096] On the other hand, if it is determined that the external illuminance does not exceed the threshold (no), then proceed... Figure 5 In step S107, the control unit 4 controls (turns on) the red LD light source 5R, the green light source 5G, and the blue light source 5B.

[0097] Then, as Figure 5As shown in step S108, road surface drawing is started by driving the MEMS mirror 3 using the drawing light L obtained by the red light RL, green light GL and blue light BL.

[0098] Next, as Figure 5 As shown in step S109, when the human body sensor reacts, a detection signal is output from the human body sensor to the control unit 4. Upon receiving the detection signal, the control unit 4 sends a stop signal to the light source unit 2 in order to stop the output of the drawing light L and stop the road surface drawing.

[0099] Next, as Figure 5 As shown in step S110, the light source unit 2, which receives the stop signal, turns off all light sources 5R, 5G, and 5B, and stops road surface drawing.

[0100] Next, as Figure 5 As shown in step S111, if the driver detection unit reacts and detects the presence of passenger H in the vehicle 100, then... Figure 5 As shown in step S112, stop (turn off) the drive of MEMS mirror 3, and then, as... Figure 5 As shown in step S113, the power to the illuminance sensor 50 and the human body sensor is turned off, and the sensing ends. Thus, the process of this embodiment ends.

[0101] As described above, in the vehicle drawing device 1 of this embodiment, when the illuminance outside the irradiation range E of the drawing light L is below a threshold, road surface drawing is performed using the drawing light L obtained by the red light RL, the green light GL, and the blue light BL.

[0102] On the other hand, when the illuminance outside the illumination range E of the aforementioned drawing light L exceeds a threshold, the red light RL is not used, but the drawing light L obtained by the green light GL and the blue light BL is used for road surface drawing.

[0103] Therefore, even when drawing roads in bright environments, the contrast of the drawing light L can be improved, thereby enhancing the visual recognizability of the drawn pattern P.

[0104] For example, in this embodiment, it is possible to form such as Figure 6A As shown, a monochrome depiction pattern P obtained by using green light GL or blue light BL, such as Figure 6B The outline pattern P obtained by using green light GL and blue light BL as shown is an example. Figure 6C The negative and positive depiction pattern P is obtained by using green light GL and blue light BL as shown.

[0105] As an example of this embodiment, the control unit 4 can also perform the following control: set a first threshold and a second threshold that is higher than the first threshold; when the external illuminance exceeds the first threshold, set the drawing light L to the first hue; when the external illuminance exceeds the second threshold, set the drawing light L to the second hue that has a contrast that is higher than the first hue.

[0106] For example, based on a first threshold and a second threshold of external illuminance (e.g., the value of external illuminance on a cloudy or sunny day), the hue of the depiction light L obtained by mixing green light GL and blue light BL is changed, and road surface depiction is performed while progressively increasing contrast.

[0107] Specifically, the external illuminance on a cloudy day (e.g., 3,000 Lux or more) is used as a first threshold. When the external illuminance exceeds the first threshold, road surface drawing is performed using a first-tone drawing light L. As a drawing pattern P utilizing the first-tone drawing light L, examples can be found using the aforementioned... Figure 6A The monochromatic depiction pattern P obtained by the green light GL or the blue light BL shown is shown.

[0108] In this case, the depiction pattern P projected onto a dark road surface T, such as asphalt, can be given contrast based on chroma. Thus, compared to the case where the road surface is depicted using a white depiction light L obtained by mixing red light RL, green light GL, and blue light BL, the visual recognizability of the depiction pattern P can be improved.

[0109] On the other hand, using an external illuminance similar to that of a sunny day (e.g., 30,000 Lux or more) as a second threshold, road surface depiction is performed using a second-tone depiction light L when the external illuminance exceeds the first threshold. The depiction pattern P based on the second-tone depiction light L can be exemplified by the above. Figure 6B The outline pattern P obtained by using green light GL and blue light BL as shown above. Figure 6C The negative and positive depiction pattern P is obtained by using green light GL and blue light BL as shown.

[0110] In this case, the chroma-based contrast and the hue-based contrast can be applied to the depicted pattern P projected onto the road surface T. Therefore, by using a depicting light L with a hue and a second hue that is higher in chroma than the first hue for road surface depiction, the visual recognizability of the depicted pattern P can be improved in bright environments.

[0111] Furthermore, regarding the drawing pattern P based on the aforementioned second-tone drawing light L, an example of an outline or negative-positive drawing pattern P obtained by green light GL and blue light BL is shown. However, in addition, for example, a colored light obtained by mixing green light GL and blue light BL (e.g., light blue light) can also be used to form an outline or negative-positive drawing pattern P. Light blue light is a bright colored light, thus increasing the contrast of chroma in addition to hue. Therefore, the visual recognizability of the drawing pattern P can be further improved.

[0112] Furthermore, for the light output of the green light source 5G and the blue light source 5B, increasing the drive current also increases the light output compared to when the external illuminance is below the first threshold. Moreover, the drive current can be controlled to further increase according to the magnitude of the external illuminance, enabling graded control of increasing the drive current between the first and second thresholds.

[0113] In an application example of this embodiment, for example, according to Figure 7 The flowchart shown illustrates the road surface depiction.

[0114] Specifically, firstly, regarding Figure 7 Steps S101 to S103 are the same as those described above. Figure 5 Similarly, in steps S101~S103, firstly, as... Figure 7 As shown in step S101, the system detects whether the key owner (passenger H) has unlocked the vehicle 100 or whether someone has approached the vehicle 100.

[0115] Next, as Figure 7 As shown in step S102, the power supply to the illuminance sensor 50 and the human body sensor (not shown), which are used for sensing, is turned on to begin sensing. Additionally, as another sensing operation, the power supply to the driver detection unit (not shown), which is capable of detecting the presence of a passenger H within the vehicle 100, is turned on.

[0116] Next, as Figure 7 As shown in step S103, in the control unit 4, the driving of MEMS mirror 3 is started (turned on), and the scanning of MEMS mirror 3 is started when each light source 5R, 5G, and 5B is turned off (turned off).

[0117] Next, in control unit 4, such as Figure 7 As shown in step S201, a determination is made as to whether the external illuminance exceeds a first threshold (e.g., 3,000 Lux).

[0118] If it is determined that the external illuminance does not exceed the first threshold (No), then, as mentioned above... Figure 5 Steps S107 and 108 are the same; proceed to... Figure 7In step S107, the control unit 4 controls (turns on) the red LD light source 5R, the green light source 5G, and the blue light source 5B.

[0119] Then, as Figure 7 As shown in step S108, road surface drawing is started by driving the MEMS mirror 3 using the drawing light L obtained by the red light RL, green light GL and blue light BL.

[0120] On the other hand, if it is determined that the external illuminance exceeds the first threshold (yes), then proceed... Figure 7 In step S202, a determination is made as to whether the external illuminance exceeds the second threshold (e.g., 30,000 Lux).

[0121] If it is determined that the external illuminance does not exceed the second threshold (No), proceed to... Figure 7 In step S203, in the control unit 4, the red light source 5R is kept off (closed), and the lighting control (opening) of the green light source 5G and the blue light source 5B is performed.

[0122] Then, as Figure 7 As shown in step S204, road surface drawing begins by driving the MEMS mirror 3 using a first-tone drawing light L obtained by green light GL and blue light BL.

[0123] At this point, for the light output of the green light source 5G and the blue light source 5B, the light output is increased by increasing the driving current compared to when the external illuminance is below the first threshold.

[0124] On the other hand, if it is determined that the external illuminance exceeds the second threshold (yes), then proceed... Figure 7 In step S205, in the control unit 4, the red light source 5R is kept off (closed), and the lighting control (opening) of the green light source 5G and the blue light source 5B is performed.

[0125] Then, as Figure 7 As shown in step S206, road surface drawing is started by driving the MEMS mirror 3 using a second-tone drawing light L obtained by green light GL and blue light BL.

[0126] At this point, for the light output of the green light source 5G and the blue light source 5B, the light output is increased by increasing the drive current compared to when the external illuminance is below the second threshold.

[0127] Next, regarding Figure 7 Steps S109 to S113 are the same as those described above. Figure 5 Similarly, in steps S109~S113, as... Figure 7As shown in step S109, when the human body sensor reacts, a detection signal is output from the human body sensor to the control unit 4. Upon receiving the detection signal, the control unit 4 sends a stop signal to the light source unit 2 in order to stop the output of the drawing light L and stop the road surface drawing.

[0128] Next, as Figure 7 As shown in step S110, the light source unit 2, which receives the stop signal, turns off all light sources 5R, 5G, and 5B, and stops road surface drawing.

[0129] Next, as Figure 7 As shown in step S111, if the driver detection unit reacts and detects the presence of passenger H in the vehicle 100, then... Figure 7 As shown in step S112, stop (turn off) the drive of MEMS mirror 3, and then, as... Figure 7 As shown in step S113, the power to the illuminance sensor 50 and the human body sensor is turned off, and the sensing ends. Thus, the process of this embodiment ends.

[0130] As described above, in the application example of this embodiment, when the external illuminance exceeds a first threshold, the road surface is drawn using the drawing light L of the first hue, and when the external illuminance exceeds a second threshold, the road surface is drawn using the drawing light L of the second hue, which has a higher hue or chroma than the first hue.

[0131] Therefore, by using a depiction light L with a hue and a chroma higher than the first hue for road surface depiction, the visual recognizability of the depicted pattern P can be further improved in bright environments.

[0132] Furthermore, the present invention is not necessarily limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.

[0133] Specifically, in the above embodiment, a structure is illustrated in which a vehicle drawing device 1 is provided in the rearview mirror 101 of the vehicle door of the vehicle 100. However, in other cases, the vehicle drawing device 1 may also be provided around the door, side, top, or bottom of the vehicle 100.

[0134] Furthermore, the vehicle drawing device 1 of this embodiment is not limited to the structure described above for drawing the road surface T, but may also be a structure for drawing the body of the vehicle 100.

[0135] Furthermore, in the vehicle drawing device 1 of this embodiment, road surface drawing is not limited to the case where the vehicle is stationary, as described above; it can also be performed while the vehicle is in motion. In this case, the drawn pattern P can be displayed, for example, as an image corresponding to the turn signal or as an "automatic navigation" display during autonomous driving.

[0136] Furthermore, in the vehicle drawing device 1 of this embodiment, the light source unit 2 is configured to use a laser light source such as a red LD chip 5R, a green LD chip 5G, and a blue LD chip 5B, but it can also be configured to use an LED light source such as a red LED chip 5R, a green LED chip 5G, and a blue LED chip 5B. When using an LED light source, it is sufficient to arrange at least one lens between the LED light source and the dichroic mirror to adjust the light emitted from the LED light source into coherent light.

[0137] Furthermore, the aforementioned light source unit 2 is configured to include light sources corresponding to the three primary colors: red light (RL), green light (GL), and blue light (BL). However, it can also be configured to include light sources emitting colors other than the three primary colors, such as orange light and white light. Moreover, regarding the number of light sources, it is also possible to configure it to include multiple light sources of the same color.

[0138] Explanation of reference numerals in the attached figures

[0139] 1… Vehicle drawing device; 2… Light source unit; 3… Scanning unit (MEMS mirror); 4… Control unit; 5R… Red LD chip (red light source); 5G… Green LD chip (green light source); 5B… Blue LD chip (blue light source); 6B… First dichroic mirror; 6G… Second dichroic mirror; 6R… Third dichroic mirror; 7R… First condenser lens; 7G… Second condenser lens; 7B… Third condenser lens; 50… Illumination sensor; 100… Vehicle; 101… Rearview mirror of vehicle door; L… Drawing light; RL… Red light; GL… Green light; BL… Blue light; E… Illumination range; H… Occupant; T… Road surface; P… Drawing pattern.

Claims

1. A vehicle drawing device, mounted on a vehicle, characterized in that, The vehicle drawing device includes: The light source unit includes multiple light sources that emit light of different wavelengths, and emits hues of depicting light corresponding to the proportions of light emitted from each light source; The scanning unit forms a drawing pattern by scanning the drawing light emitted from the light source unit; as well as The control unit, by controlling the illumination of the plurality of light sources, can variably control the hue of the depicting light and the depicting pattern. When the illuminance outside the illumination range illuminated by the depicting light exceeds a threshold, the control unit turns off one of the multiple light sources that emits the longest wavelength light, and performs illumination control for the other light sources.

2. The vehicle drawing device according to claim 1, characterized in that, When the external illuminance exceeds a threshold, the control unit controls the output of the other light sources to increase compared to before the threshold is exceeded.

3. The vehicle drawing device according to claim 1, characterized in that, The light source unit includes a red light source that emits red light, a green light source that emits green light, and a blue light source that emits blue light. When the external illuminance exceeds a threshold, the control unit turns off the red light source and controls the lighting of the green and blue light sources.

4. The vehicle drawing device according to claim 1, characterized in that, The wavelength of the light emitted by the light source is above 620nm.

5. The vehicle drawing device according to claim 1, characterized in that, The wavelength of light emitted by the other light sources is below 565nm.

6. The vehicle drawing device according to claim 5, characterized in that, The other light sources include at least GaN-based light-emitting elements.

7. The vehicle drawing device according to claim 6, characterized in that, The other light sources include green light sources emitting green light and blue light sources emitting blue light, wherein the green light sources include GaN-based or InGaN-based light-emitting elements. The blue light source includes GaN-based light-emitting elements.

8. The vehicle drawing device according to claim 1, characterized in that, The depiction pattern is formed by an outlined depiction pattern obtained through different colored lights or a negative-positive depiction pattern.

9. The vehicle drawing device according to claim 1, characterized in that, The multiple light sources are laser light sources.

10. The vehicle drawing device according to claim 1, characterized in that, The control unit determines whether the external illuminance exceeds a threshold based on the external illuminance detected by the illuminance sensor mounted on the vehicle.

11. The vehicle drawing device according to claim 1, characterized in that, The control unit determines whether the external illuminance exceeds a threshold based on external illuminance information provided via a communication unit mounted on the vehicle.

12. The vehicle drawing device according to claim 1, characterized in that, The control unit sets a first threshold and a second threshold that is higher than the first threshold. When the external illuminance exceeds the first threshold, the depicting light is set to the first hue. When the external illuminance exceeds the second threshold, control is performed to set the drawing light to a second hue with a higher contrast than the first hue, either in hue or chroma.

13. The vehicle drawing device according to claim 12, characterized in that, The depicting light for the first hue is green light, blue light, or monochromatic light obtained by mixing green and blue light. The second hue of the depicting light is green light, blue light, or monochromatic light obtained by mixing green light and blue light, which has a higher contrast in hue or chroma than the first hue of the depicting light.

14. The vehicle drawing device according to claim 1, characterized in that, The depicted pattern is projected onto the road surface.

15. The vehicle drawing device according to claim 1, characterized in that, The depicted pattern is projected onto the vehicle body.

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