JP5668958B2 - Vehicle headlamp - Google Patents

Description

  The present invention relates to a vehicle headlamp, and more particularly to a vehicle headlamp capable of improving the visibility (awareness) of surrounding pedestrians and obstacles in an actual traffic environment.

  Conventionally, in the field of headlamps, it has been demanded to improve the brightness so that it can be driven at night as well as in the daytime. In order to meet this demand, a high luminous flux light source such as a halogen lamp or an HID lamp is used to provide an optical system. Various headlamps have been proposed with the aim of improving brightness such as improving the brightness (see, for example, Patent Document 1 and Patent Document 2).

JP 2007-59162 A Japanese Patent Laid-Open No. 11-273407

  However, cones that are densely located in the central part of the retina and capture the color of the central part of the field of view in bright places, rods that are distributed in the peripheral part of the retina and function in dark places, central vision, peripheral vision, color matching functions, specific visual sensitivity curves, etc. When the visual characteristics based on the above are taken into consideration (see FIGS. 56 to 59), the visibility (awareness) of surrounding pedestrians and obstacles in the actual traffic environment should be affected by these visual characteristics, Simply turning the power on and making the headlamps brighter goes against social trends that focus on environmental issues, and more efficiently improves the visibility (awareness) of surrounding pedestrians and obstacles. There is also a problem of going backwards in improving performance.

  The present invention has been made in view of such circumstances, and provides a vehicle headlamp capable of improving the visibility (awareness) of surrounding pedestrians and obstacles in an actual traffic environment. For the purpose.

In order to solve the above-mentioned problem, the invention according to claim 1 is directed to a vehicle headlamp configured to emit light in a predetermined white range, wherein the vehicle headlamp is a first headlamp. A plurality of headlamp units including a unit and a second headlamp unit, wherein the first headlamp unit has a first LED light source and an incident surface on which light emitted from the first LED light source is incident The second headlamp unit includes a second LED light source, an incident surface on which light emitted from the second LED light source is incident, and an emission surface. The first lens light source and the second LED light source have a color temperature of 4500 to 70. The second LED light source has a surface and a second lens body adjacent to the first lens body. 0 is the [K], and, four-color four coordinate values representing the prediction of the definitive appearance when irradiated with color chips (red, green, blue and yellow) (a *, b *) is, CIE1976L * a * b * Coordinate value R (41.7,20.9), G (-39.5,14.3), B (8.8, -29.9) on the coordinate system where the vertical axis corresponding to space is a * axis and the horizontal axis is b * axis , Y (-10.4, 74.2) is a light source included in a circular range with a radius of 5, and the light emitted from the first headlamp unit is on a vertical screen disposed at a predetermined position in the irradiation direction A first light distribution pattern is formed, light emitted from the second headlamp unit forms a second light distribution pattern on the vertical screen, and the second light distribution pattern is the first light distribution pattern. than 1 of the light distribution pattern Ri wide light distribution pattern der in the vehicle traveling direction outer side, the first LED light source and the second LED light source, a blue or ultraviolet Using a white LED light source that includes a light LED element and a wavelength conversion material, or an LED light source that is a combination of red, green, and blue LEDs, coordinate values on the xy chromaticity coordinates (0.323, 0.352), (0.325 , 0.316), (0.343, 0.331), and (0.368, 0.379) are irradiated with white light in a chromaticity range surrounded by a straight line .

  The conditions described in claim 1 were found as a result of an experiment conducted by the inventors of the present application. According to the invention described in claim 1, in the actual traffic environment (especially when turning right at an intersection). Visibility (awareness) of surrounding pedestrians and obstacles can be improved.

The invention according to claim 4 is the invention according to any one of claims 1 to 3, wherein the light source has a ratio of a radiant energy amount present at a wavelength of 450 to 550 nm to a radiant energy amount present in a visible light region. It is characterized by being higher than the halogen lamp light source .

  The fourth aspect specifies that the light source is an LED light source.

  ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the headlamp for vehicles which can improve the visibility (awareness) with respect to the surrounding pedestrian, an obstruction, etc. in an actual traffic environment.

It is a figure for demonstrating the white range A1 of the headlamp prescribed | regulated by the regulation. It is a figure for demonstrating the apparatus structure used for the experiment 1 for clarifying the white range favored as light of a headlamp. (A) The figure which plotted the measurement result (group 1) of experiment 1 on xy chromaticity coordinates, (b) (a) The figure which plotted the measurement result (group 2) of experiment 1 on xy chromaticity coordinates. . (A) The figure which plotted the measurement result (group 1) of experiment 1 on xy chromaticity coordinates, (b) (a) The figure which plotted the measurement result (group 2) of experiment 1 on xy chromaticity coordinates. . (A) The figure which plotted the measurement result (group 1) of experiment 1 on xy chromaticity coordinates, (b) (a) The figure which plotted the measurement result (group 2) of experiment 1 on xy chromaticity coordinates. . (A) The figure which plotted the measurement result (group 1) of experiment 1 on xy chromaticity coordinates, (b) (a) The figure which plotted the measurement result (group 2) of experiment 1 on xy chromaticity coordinates. . The figure for demonstrating the approximate range accept | permitted as the light of a headlamp clarified from the measurement result (group 1) of experiment 1, (b) The head clarified from the measurement result (group 2) of experiment 1 It is a figure for demonstrating the approximate range accept | permitted as the light of a lamp | ramp. It is a figure for demonstrating the white range A2 preferred as the light of the headlamp which became clear from Fig.7 (a) (b). To explain that in an actual traffic environment (especially when turning right at an intersection), the driver recognizes surrounding pedestrians and obstacles with peripheral vision while viewing the oncoming vehicle V1 with central vision. FIG. It is a figure for demonstrating the apparatus structure used for the experiment 2 for clarifying the white range (chromaticity range of the light color as a headlamp) which can improve the visibility (awareness) by peripheral vision. . It is a figure for demonstrating the correlation chromaticity etc. of the light source used for experiment 2 grade | etc.,. It is the graph which plotted the relationship between the reaction time measured by Experiment 2, and the presentation position for every light source. (A) Table which evaluated each light source based on reaction time etc., (b) It is a graph showing the relationship between each light source and evaluation score. It is the graph which plotted the relationship between the miss rate calculated based on the reaction time measured by Experiment 2, and the presentation position for each light source. It is a figure for demonstrating the concept of the reaction number ratio. It is a graph showing the relationship between the reaction number ratio of the light source (luminance: 1 cd / m < ² >) used for Experiment 2, and reaction time. It is a graph showing the relationship between the reaction number ratio of the light source (luminance: 0.1 cd / m < ² >) used for Experiment 2, and reaction time. It is a graph showing the relationship between the reaction number ratio of the light source (luminance: 0.01 cd / m < ² >) used for Experiment 2, and reaction time. It is the graph which averaged the graph shown in FIGS. It is a graph for demonstrating that the visibility (awareness) by peripheral vision is improving, so that the light source with high color temperature is related to the awareness with respect to white light. It is a figure for demonstrating the apparatus structure used for the experiment 3 for clarifying whether there exists a difference in the visibility (awareness) by peripheral vision with respect to colors other than white. It is a graph showing the relationship between the reaction number ratio of the light source used for Experiment 3, and reaction time. It is the graph which plotted the reciprocal number of the average reaction time with respect to the color material of the light source used for Experiment 3 in the coordinate system which is Yellow on the + side of a vertical axis | shaft, Blue on the negative side, Red on the horizontal side, and Green on the-side. It is the graph which averaged four graphs shown in FIG. It is a graph showing the relationship between each light source and an evaluation score. It is a graph for demonstrating the fact that the sensitivity with respect to a specific wavelength (450-550 nm) becomes high compared with the state of photopic vision in the state of scotopic vision (the state of twilight vision is the same). It is a figure for demonstrating the fact that there exists a tendency for a radiant energy component ratio to become high, so that a light source with high color temperature. It is a figure for demonstrating white range A3 (chromaticity range of the light color as a headlamp) which can improve the visibility (perception) by peripheral vision. It is a figure for demonstrating that it is LED whose color temperature is 5000 [K] or more that notice time is shorter than TH and HID. It is a figure for demonstrating the area | region etc. from which the relationship with notice is not clarified by Experiment 2 and Experiment 3. FIG. It is the graph which plotted for each light source the relationship between the miss rate calculated based on the reaction time measured by the additional experiment (ratio which passed 2 second or more to notice presentation light), and the presentation position. It is a graph showing the relationship between the reaction number ratio of the light source (luminance: 1 cd / m < ² >) used for the additional experiment, and reaction time. It is a graph showing the relationship between the reaction number ratio of the light source (luminance: 0.1 cd / m < ² >) used for the additional experiment, and reaction time. It is a graph showing the relationship between the reaction number ratio of the light source (luminance: 0.01 cd / m < ² >) used for the additional experiment, and reaction time. It is the graph which averaged the graph shown in FIGS. It is a figure for demonstrating the white range (chromaticity range of the light color as a headlamp) which can improve the visibility (awareness) by peripheral vision. Prediction of the appearance of four colors (red, green, blue, yellow) for each TH, HID, LED (T9) calculated by using a known formula based on the spectrum of TH, HID, LED (T9) The four coordinate values are represented by the a ^* -b ^* coordinate system corresponding to the CIE1976L * a * b * space (a ^* is in the red direction, -a ^* is in the green direction, b ^* is in the yellow direction, and -b ^* is in the blue direction. It is a graph plotted in FIG. Other than the LED (T9), other LEDs (T6, T7, etc.) have four coordinate values R (41.7,20.9), G (-39.5,14.3), B (8.8, -29.9), Y (-10.4, 74.2) is a diagram for explaining that it is included in a circle range with a radius of 5 centering on Y. It is a figure for demonstrating arrangement | positioning etc. of the headlamp 100 of this embodiment. It is an enlarged view of the headlamp 100 arrange | positioned on the left side. It is an example of the light distribution pattern formed on a vertical screen by the headlamp 100 arrange | positioned on the left side. It is a figure for demonstrating that the light source with a high ratio of a radiant energy component has little fall of reaction time, even if brightness | luminance becomes low. It is a figure for demonstrating that the light source with a high ratio of a radiant energy component has little fall of reaction time, even if brightness | luminance becomes low. It is a figure for demonstrating that the light source with a high ratio of a radiant energy component has little fall of reaction time, even if brightness | luminance becomes low. It is a figure for demonstrating that the light source with a high ratio of a radiant energy component has little fall of reaction time, even if brightness | luminance becomes low. It is the light distribution pattern (luminous intensity distribution) formed on the vertical screen by the headlamp 100 of this embodiment. It is a light distribution pattern (light intensity distribution) formed on the vertical screen by the headlamp of Conventional Example 1. It is a road surface light distribution pattern (isoluminance distribution) formed on the road by the headlamp 100 of this embodiment. It is a road surface light distribution pattern (equal illumination distribution) formed on the road by the headlamp of Conventional Example 1. It is a road surface light distribution pattern (equal illumination distribution) formed on the road by the headlamp of Conventional Example 2. It is the graph which put together the evaluation result of run ease. It is a figure for demonstrating the arrangement | positioning location of the color mark C1. It is the graph which put together the evaluation result of the visibility of the color at the time of driving | running | working. (A) The figure for demonstrating the arrangement | positioning locations, such as color target C2, (b) The table | surface for demonstrating the arrangement locations, such as color target C2. It is the graph which put together the evaluation result of the visibility of the color in the scene at the time of the intersection right turn. It is a figure for demonstrating the visual characteristic based on a cone, a rod, central vision, peripheral vision, etc. FIG. It is a figure for demonstrating the visual characteristic based on a cone, a rod, central vision, peripheral vision, etc. FIG. It is a figure for demonstrating the visual characteristic based on a cone, a rod, central vision, peripheral vision, etc. FIG. It is a figure for demonstrating the visual characteristic based on a cone, a rod, central vision, peripheral vision, etc. FIG.

  The conditions for improving the visibility (awareness) of surrounding pedestrians and obstacles in the actual traffic environment (especially when turning right at the intersection) will be clarified below.

[White range preferred for headlamp light]
The white range A1 of the headlamp (the chromaticity range of the light color as the headlamp) is defined by law (see FIG. 1). However, the white range A1 of headlamps stipulated by regulations (coordinate values on xy chromaticity coordinates (0.31,0.28), (0.44,0.38), (0.50,0.38), (0.50,0.44), (0.455,0.44 ), (0.31,0.35) is a chromaticity range surrounded by a straight line), which is determined regardless of whether it is preferred as light of the headlamp. It is not always preferred as light. Therefore, the inventor of the present application conducted the following experiment in order to clarify the white range preferred as the headlamp light in the white range A1 defined by the law.

[Experiment 1]
Experimental environment: A dark room in which RGB (red, green, blue) LEDs and a diffusion board that diffuses light emitted from the LEDs were arranged was used (see FIG. 2). There are 6 subjects, 3 in Group 1 and 3 in Group 2.

  Experimental procedure: The light source color for controlling the LED and illuminating the diffusion board is gradually changed in the direction of the arrow shown in FIGS. 3 (a) (b) to 6 (a) (b), through the opening of the dark room. When the stimulus light to be presented entered the subject's favorite white range, the push button was pressed, and the chromaticity at the time when the push button was pressed was measured.

  As a result of plotting the above measurement results on the xy chromaticity coordinates (see FIGS. 3 (a) (b) to 6 (a) (b)) and examining, there is an approximate range allowed as light of the headlamp. It becomes clear (see FIGS. 7 (a) and 7 (b)), and the white range (the chromaticity range of the light color as the headlamp) preferred as the light of the headlamp is a coordinate value on the chromaticity coordinates shown in FIG. It became clear that it was the chromaticity range A2 surrounded by P1 to P4.

[White range that can improve visibility (perception) by peripheral vision]
In an actual traffic environment (especially when turning right at an intersection), as shown in FIG. 9, in general, the driver visually recognizes the oncoming vehicle V1 in the central view, while seeing surrounding pedestrians and obstacles in the peripheral view. It seems that they are aware.

  The inventor of the present application is able to improve the visibility (awareness) by peripheral vision among the white range A2 preferred as the light of the above-described headlamp (the chromaticity of the light color as the headlamp). The following experiment was conducted to clarify the range.

[Experiment 2]
Experimental environment: An apparatus having the configuration shown in FIG. 10 was used, and a plurality of light sources (T1 to T11, TH, HID) having different correlated color temperatures were used as the light source of the presenting light as shown in FIG. T1 to T11 represent LEDs, TH represents a halogen lamp, and HID represents an HID lamp. There are 18 subjects.

Experimental procedure: While the subject is gazing at the display (the hiragana is displayed) 2 m in front, the left (or right) 30 °, 45 °, 60 °, and 75 ° positions with respect to the front The gray color materials irradiated by the light sources (T1 to T11, TH, HID) adjusted to a constant luminance (1, 0.1 cd / m ² ) at (angular position) are sequentially presented, and each light source and presentation position is presented. The time (reaction time) until the subject visually recognizes (notices) the presented light (reflected light from the gray color material) was measured.

[Reaction time for each light source and presentation position]
FIG. 12 is a graph in which the relationship between the reaction time measured in Experiment 2 and the presentation position is plotted for each light source. FIG. 13A (column of “reaction time”) is a table in which each light source is evaluated based on the reaction time. A light source with a shorter reaction time can be said to have improved visibility (awareness) in peripheral vision. Therefore, a higher evaluation score was assigned to a light source with a shorter reaction time.

  Referring to FIG. 12 and FIG. 13A (column of “Reaction time”), the light source having a higher color temperature tends to have a shorter reaction time (higher evaluation score), that is, the color regarding the awareness of white light. It can be seen that the higher the temperature of the light source, the better the visibility (awareness) by peripheral vision.

[Missing rate]
FIG. 14 is a graph in which the relationship between the missed rate calculated based on the reaction time measured in Experiment 2 (the rate at which 2 seconds or more have passed to notice the presented light) and the presented position is plotted for each light source. FIG. 13A (column of “missing rate”) is a table in which each light source is evaluated based on the missing rate. Since it can be said that the visibility (awareness) of peripheral vision is improved with a light source with a small miss rate, a higher evaluation score is assigned to a light source with a small miss rate.

  Referring to FIG. 14 and FIG. 13A (column of “missing rate”), the light source having a higher color temperature tends to have a smaller missing rate (higher evaluation score), that is, color awareness regarding white light. It can be seen that the higher the temperature of the light source, the better the visibility (awareness) by peripheral vision.

[Reaction number ratio]
FIG. 15 is a diagram for explaining the concept of the reaction number ratio. The ratio of the number of reactions means (number of reactions up to a certain time) / (number of data with a reaction time of 2 seconds or less out of the total number of reactions). The time that half of the subjects noticed was evaluated as the response time to the light source. The reaction time of 2 seconds or longer was defined as missed.

FIG. 16 is a graph showing the relationship between the reaction number ratio of the light source (luminance: 1 cd / m ² ) used in Experiment 2 and the reaction time.

  Referring to Figure 16, the order in which the reaction rate ratio reaches 0.5 is T10⇒T8⇒T5⇒T3⇒T7⇒T9⇒T6⇒HID⇒T11⇒T2⇒T1⇒TH⇒T4. From the above, it can be seen that the light source with a higher color temperature tends to have a shorter reaction time until the reaction rate ratio reaches 0.5, that is, the light source with a higher color temperature has a higher visibility due to peripheral vision. It can be seen that (Awareness) has improved.

FIG. 17 is a graph showing the relationship between the reaction number ratio of the light source (luminance: 0.1 cd / m ² ) used in Experiment 2 and the reaction time.

  Referring to FIG. 17, the order in which the reaction rate ratio reaches 0.5 is T8⇒T5⇒T7⇒HID⇒T9⇒T6⇒T11⇒T1⇒T10⇒T3⇒T4⇒T2⇒TH. From the above, it can be seen that the light source with a higher color temperature tends to have a shorter reaction time until the reaction rate ratio reaches 0.5, that is, the light source with a higher color temperature has a higher visibility due to peripheral vision. It can be seen that (Awareness) has improved.

FIG. 18 is a graph showing the relationship between the reaction number ratio of the light source (luminance: 0.01 cd / m ² ) used in Experiment 2 and the reaction time.

  Referring to FIG. 18, the order in which the reaction rate ratio reaches 0.5 is T5⇒T8⇒T9⇒HID⇒T11⇒T10⇒T6⇒T2⇒T7⇒T3⇒T1⇒T3⇒TH. From the above, it can be seen that the light source with a higher color temperature tends to have a shorter reaction time until the reaction rate ratio reaches 0.5, that is, the light source with a higher color temperature has a higher visibility due to peripheral vision. It can be seen that (Awareness) has improved.

  FIG. 19 is a graph obtained by averaging the graphs shown in FIGS. FIG. 13A (column of “reaction number ratio”) is a table in which each light source was evaluated based on the reaction time until the reaction number ratio 0.5 was reached. Since it can be said that the visibility (awareness) by peripheral vision is improved as the light source has a shorter reaction time until reaching the reaction number ratio 0.5, the light source has a shorter reaction time until the reaction number ratio 0.5 is reached. A higher evaluation score was assigned.

  Referring to Fig. 19 and Fig. 13 (a) ("Reaction number ratio" column), the order in which the reaction number ratio reaches 0.5 is T8⇒T5⇒HID⇒T9⇒T10⇒T7⇒T11⇒T6⇒ T2⇒T1⇒T3⇒T4⇒TH in this order. From this, the light source with higher color temperature tends to have a shorter reaction time until reaching the reaction number ratio 0.5, that is, for white light With regard to awareness, it can be seen that the light source having a higher color temperature has improved visibility (awareness) in peripheral vision.

  When each light source is comprehensively evaluated based on the total points of the reaction time, reaction rate ratio, and miss rate (see FIGS. 13 (a) and 13 (b)) that are scored as described above, It can be seen that the higher the temperature of the light source, the better the visibility (awareness) by peripheral vision (see FIG. 20).

[Awareness of color materials]
In an actual traffic environment, it is not only white light that is irradiated and reflected from the headlamp. The inventor of the present application conducted the following experiment in order to clarify whether there is a difference in visibility (awareness) in peripheral vision for colors other than white.

[Experiment 3]
Experimental environment: A device having the configuration shown in FIG. 21 was used, and a plurality of light sources (T5, T6, T7, T9, TH, HID) having different correlated color temperatures were used as the light source of the presenting light as shown in FIG. T5, T6, T7, and T9 represent LEDs, TH represents a halogen lamp, and HID represents an HID lamp. There are 18 subjects.

  Experimental procedure: While the subject is gazing at the display (the hiragana is displayed) 2 m in front, the left (or right) 30 °, 45 °, 60 °, and 75 ° positions with respect to the front The color materials (red / green / blue / yellow) irradiated by the light source (T5, T6, T7, T9, TH, HID) adjusted to a constant luminance at (angular position) are sequentially presented, the light source, the presentation position, For each color material, the time (reaction time) until the subject visually recognizes (notices) the presented light was measured.

  FIG. 22 is a graph showing the relationship between the reaction number ratio of the light source used in Experiment 3 and the reaction time.

  Referring to FIG. 22, regarding the awareness of the color material, it can be seen that the light source having a short reaction time until reaching the reaction number ratio of 0.5 is the LED (T9).

  FIG. 23 plots the reciprocal of the average reaction time for the light source color material used in Experiment 3 in a coordinate system in which the positive side of the vertical axis is Yellow, the negative side is Blue, the positive side of the horizontal axis is Red, and the negative side is Green. It is a graph. It shows that the visibility (awareness) by the peripheral vision is improved as the light source having a larger diamond connecting the coordinate values.

  FIG. 24 is a graph obtained by averaging the four graphs shown in FIG. Referring to FIG. 24, the LED has a larger rhombus connecting the coordinate values than TH and HID, that is, the perception of color (coloring material), and visibility (awareness) by peripheral vision rather than TH and HID. It can be seen that is improved.

  When the results of Experiment 2 and Experiment 3 are combined, regarding the awareness of white light and color (coloring material), the light source with a higher color temperature tends to have a higher evaluation score, and the visibility (awareness) by peripheral vision is improved. (See FIG. 25). This is due to the fact that the sensitivity to a specific wavelength (450 to 550 nm) is higher in the scotopic state (similar to the twilight state) (see FIG. 26), and the light source has a high color temperature. This is consistent with the fact that the radiant energy component ratio (see FIG. 26 for the definition of the radiant energy component ratio) tends to be high (see FIG. 27).

  Summing up the above, FIG. 28 shows the white range (the chromaticity range of the light color as a headlamp) that can improve the visibility (awareness) by peripheral vision regarding the awareness of white light and color (coloring material). It can be seen that the chromaticity range A3 is surrounded by the coordinate values P1, P2, P5, and P6 on the xy chromaticity coordinates shown.

  This chromaticity range A3 (see FIG. 28), the facts made clear above (the light source having a higher color temperature improves the visibility (awareness) by peripheral vision. See FIGS. 13 (a) and 13 (b)), Furthermore, considering that LEDs that have a color temperature of 5000 [K] or higher are shorter than TH and HID (see FIG. 29), the conditions for improving the visibility (awareness) of peripheral vision are One shows that the color temperature is 5000 to 6000 [K].

  The inventor of the present application has a region (see FIG. 30) in the white range A2 that is preferred as the light of the above-described headlamp, in which the relationship with the awareness is not clarified by the experiments 2 and 3 (see FIG. 30) In order to clarify whether it is possible to improve visibility (awareness) by visual observation, the following additional experiment was conducted.

[Additional experiment]
Experimental environment: Using the apparatus having the configuration shown in FIG. 10, as the light source of the presenting light, a plurality of light sources (T1 to T11, TH, HID) having different correlated color temperatures as shown in FIG. 11, and the correlated color shown in FIG. Temperature LEDs (T15, T17) were used. T1 to T11, T15, and T16 are LEDs, TH is a halogen lamp, and HID is an HID lamp. There are 18 subjects.

Experimental procedure: While the subject is gazing at the display (the hiragana is displayed) 2 m in front, the left (or right) 30 °, 45 °, 60 °, and 75 ° positions with respect to the front The light source (T1 to T11, T15, T17, TH, HID) adjusted to a constant luminance (1, 0.1 cd / m ² ) is sequentially presented at (angular position), and the subject presents light for each light source and presentation position. The time (reaction time) to visually recognize (recognize) was measured.

[Reaction time for each light source and presentation position]
Since the relationship between the reaction time measured by the additional experiment and the presentation position is the same as in Experiment 2 (see FIG. 12), the description thereof is omitted.

[Missing rate]
FIG. 31 is a graph in which the relationship between the missed rate calculated based on the reaction time measured by the additional experiment (the rate at which 2 seconds or more have passed to notice the presented light) and the presented position is plotted for each light source. After correcting the reaction time data based on HID, the miss rate was calculated.

  Referring to FIG. 31, it can be seen that the LED (T15) corresponds to a missing rate comparable to that of a light source having a low color temperature.

[Reaction number ratio]
FIG. 32 is a graph showing the relationship between the reaction number ratio of the light source (luminance: 1 cd / m ² ) used in the additional experiment and the reaction time. After correcting the reaction time data based on HID, the reaction number ratio was calculated.

  Referring to FIG. 32, the order in which the reaction rate ratio reaches 0.5 is as follows: T10 → T8 → T5 = T3 = T7 = T6 = HID = T9 = T11 = T15 → T2 → T17 → T1 → TH → T4 It turns out that it is.

FIG. 33 is a graph showing the relationship between the reaction number ratio of the light source (luminance: 0.1 cd / m ² ) used in the additional experiment and the reaction time. After correcting the reaction time data based on HID, the reaction number ratio was calculated. Referring to FIG. 33, the order in which the reaction rate ratio reaches 0.5 is as follows: T8 → T7 = T5 = HID = T15 = T6 → T11 → T9 → T1 → T10 → T3 → T17 → T4 → T2 → TH It turns out that it is.

FIG. 34 is a graph showing the relationship between the reaction number ratio of the light source (luminance: 0.01 cd / m ² ) used in the additional experiment and the reaction time. After correcting the reaction time data based on HID, the reaction number ratio was calculated. Referring to FIG. 34, the order in which the reaction rate ratio reaches 0.5 is as follows: T5 → T8 = T9 = HID = T11 = T15 = T10 → T6 → T2 → T7 → T4 → T1 → T17 → T3 → TH It turns out that it is.

  FIG. 35 is a graph obtained by averaging the graphs shown in FIGS. Referring to FIG. 35, the order in which the reaction ratio reaches 0.5 is as follows: T5 → T8 → T9 = HID = T10 = T7 = T11 = T6 = T15 → T2 → T1 → T3 → T4 → T17 → TH That is, it can be seen that the reaction time of H15 is almost equal to that of HID.

  As a result of the additional experiment, it has been clarified that the reaction time of the LED (T15) is equivalent to that of a light source having a high color temperature, and the reaction time of the LED (T17) behaves similarly to a light source having a low color temperature. .

  Combining the results of Experiment 1 to Experiment 3 and the additional experiment, the white range (the chromaticity range of the light color as the headlamp) that can improve the visibility (awareness) by peripheral vision is shown in FIG. It can be seen that the chromaticity range A4 is surrounded by a straight line connecting the coordinate values (0.323, 0.352), (0.325, 0.316), (0.343, 0.331), and (0.368, 0.379) on the chromaticity coordinates.

  This chromaticity range A4 (see FIG. 36) and the above-described fact (the light source having a higher color temperature improves visibility (awareness) in peripheral vision. See FIGS. 13 (a) and 13 (b)). In consideration, it can be seen that one of the conditions for improving the visibility (awareness) by peripheral vision is a color temperature of 4500 to 7000 [K].

[Prediction of color appearance]
Even if they are the same color, they look different if the light source is different. It is generally explained that this is due to the change in the spectral distribution of the light source and the fact that the eyes get used to it (adaptation) when the light source color changes. The color appearance is not completely but can be predicted by using a known formula.

FIG. 37 shows the appearance of four colors (red, green, blue, and yellow) for each TH, HID, and LED (T9) calculated using known formulas based on the respective spectra of TH, HID, and LED (T9). The four coordinate values representing the prediction of the direction are represented by the a ^* -b ^* coordinate system corresponding to the CIE1976L * a * b * space (a ^* is in the red direction, -a ^* is in the green direction, b ^* is in the yellow direction, -b ^(* Represents the blue direction). This represents prediction about the appearance of the color for each TH, HID, and LED (T9). In FIG. 37, the closer each coordinate value is to 100 (that is, the light source having a larger rhombus connecting the four coordinate values), the more the color (color chart) looks like the reference light source (sunlight, color temperature: 6500 [K ]) Approaching the appearance under illumination (that is, the color can be reproduced more faithfully).

  Referring to FIG. 37, the LED (T9) has four coordinate values R (41.7, 20.9), G (-39.5, 14.3), B (8.8, -29.9), Y (-10.4, compared with TH and HID. 74.2) is large, that is, the appearance of the color (color chart) under the illumination of the LED (T9) is the appearance of the color (color table) under the illumination of the standard light source compared to TH and HID It can be seen that it is closer (that is, the color can be reproduced more faithfully).

  Referring to FIG. 38, other LED (T6, T7, etc.) other than LED (T9) have four coordinate values R (41.7, 20.9), G (-39.5, 14.3). ), B (8.8, -29.9), Y (-10.4,74.2) is included in a circle with radius 5 and has four coordinate values compared to TH and HID, similar to LED (T9). Is large, that is, the appearance of the color (color table) under illumination of other LEDs (T6, T7, etc.) other than LED (T9) is also under the illumination of a standard light source compared to TH and HID It can be seen that the color (color table) is closer to the appearance (that is, the color can be reproduced more faithfully).

In summary, the four coordinate values representing the prediction of the appearance of the four colors (red, green, blue, yellow) are coordinate values on the a ^* -b ^* coordinate system corresponding to the CIE1976L * a * b * space. It is possible to use an LED light source included in a circular range with a radius of 5 centered on R (41.7,20.9), G (-39.5,14.3), B (8.8, -29.9), Y (-10.4,74.2). It can be seen that this is a condition for reproducing the image more faithfully.

  This condition is that the white range that can improve the visibility (awareness) by peripheral vision is the chromaticity range A3 (or chromaticity range A4), and the fact that has been clarified above (light source with high color temperature) Considering that the visibility (awareness) by peripheral vision is improved, see FIGS. 13 (a) and 13 (b)), which is one of the conditions for improving the visibility (awareness) by peripheral vision. It can be said that it can be said.

In summary, the conditions for improving the visibility (awareness) of peripheral vision are: a color temperature of 4500 to 7000 [K] (preferably 5000 to 6000 [K]), and four colors (red, green, The four coordinate values representing the prediction of the appearance of blue and yellow) are the coordinate values R (41.7,20.9), G (-39.5,) on the a ^* -b ^* coordinate system corresponding to the CIE1976L * a * b * space. 14.3), B (8.8, -29.9), Y (-10.4, 74.2), it turns out that it is using the LED light source (or light source equivalent to this) contained in the circle | round | yen range of radius 5. More preferably, the light color as the headlamp is surrounded by a straight line connecting the coordinate values (0.323, 0.352), (0.325, 0.316), (0.343, 0.331), (0.368, 0.379) on the xy chromaticity coordinates. It can be seen that the chromaticity range is A4 (see FIG. 36).

  As a light source satisfying these conditions, for example, there are LEDs (T6, T7, T9) having correlated color temperatures shown in FIG.

  It is known that the LED is about 10% brighter than TH and HID in the scotopic vision state (similar to the twilight vision state). From this point, the LED light source is used as the light source of the headlamp 100. 11 may be advantageous.

[Configuration of headlamp]
Next, a description will be given of a configuration example of a headlamp that satisfies the conditions for improving the visibility (awareness) of the above-described peripheral vision.

  As shown in FIG. 39, the headlamp 100 of the present embodiment is disposed on each of the left and right sides of the front portion of the vehicle. Since the left and right headlamps 100 are bilaterally symmetrical and have the same configuration, the left headlamp 100 will be mainly described below.

  FIG. 40 is an enlarged view of the headlamp 100 arranged on the left side.

  The headlamp 100 of the present embodiment has a configuration in which four headlamp units 10A to 10D are arranged in the horizontal direction.

  The headlamp units 10 </ b> A to 10 </ b> D include, as a common configuration, an LED light source 11, a lens body 12 disposed in front of the LED light source 11, a heat sink 13 for heat dissipation to which a substrate on which the LED light source 11 is mounted is fixed. ing.

The LED light source 11 is an LED light source that satisfies the conditions for improving the visibility (awareness) by the above-described peripheral vision, that is, a color temperature of 4500 to 7000 [K] (preferably 5000 to 6000 [K]), The four coordinate values representing the prediction of the appearance of the four colors (red, green, blue, yellow) are coordinate values R (41.7 on the a ^* −b ^* coordinate system corresponding to the CIE1976L * a * b * space. , 20.9), G (-39.5, 14.3), B (8.8, -29.9), and Y (-10.4, 74.2).

  As the LED light source 11, for example, an LED light source in which a blue LED and a yellow phosphor are combined, for example, LEDs (T6, T7, T9) having correlated color temperatures shown in FIG. 11 can be used. In this case, for example, by adjusting the concentration and composition of the yellow phosphor, it is possible to configure an LED light source that satisfies the conditions for improving the above-described visibility (awareness). Alternatively, as the LED light source 11, it is also possible to use an LED light source that combines an ultraviolet LED and a white (three primary colors) phosphor, or an LED light source that combines a red, green, and blue three-color LED.

  Hereinafter, an example in which an LED light source (correlated color temperature: 6000 [K], luminous flux: 1100 [lm]) in which a blue LED and a yellow phosphor are combined is used as the LED light source 11 will be described.

  The lens body 12 includes an incident surface 12a on which light emitted from the LED light source 11 enters the lens, both side reflection surfaces 12b and 12c on which light from the LED light source 11 incident on the lens is internally reflected, and both side reflection surfaces. It is a solid lens body including an exit surface 12d from which light from the LED light source 11 reflected by 12b and 12c exits.

  As the lens body 12, for example, a lens body disclosed in JP 2009-238469 A or a lens body having other configurations can be used.

  The lens bodies 12 of the headlamp units 10A to 10D are arranged so that the inclination angle with respect to the reference axis AX0 extending in the vehicle front-rear direction increases from the vehicle center toward the outside (left side in FIG. 40). Hereinafter, the lens body 12 on the vehicle center side is the first lens body 12A, the lens body 12 adjacent to the outside is the second lens body 12B, the lens body 12 adjacent to the outside is the third lens body 12C, and the outside is adjacent to the outside. The lens body 12 that performs this operation is referred to as a lens body 12D.

  The first lens body 12A is arranged so that its optical axis AX1 coincides with the reference axis AX0. The incident surface 12a, both-side reflecting surfaces 12b and 12c, and the exit surface 12d of the first lens body 12A are spot-shaped first on a vertical screen on which light from the LED light source 11 incident on the lens is disposed at a predetermined position in front. The light distribution pattern P1 (see FIG. 41) is formed.

  The second lens body 12B is disposed in a posture in which the optical axis AX2 is inclined outward with respect to the reference axis AX0 (7 ° is illustrated in FIG. 40). The incident surface 12a, the both-side reflecting surfaces 12b and 12c, and the emitting surface 12d of the second lens body 12B have a first light distribution pattern on a vertical screen in which light from the LED light source 11 incident on the lens is disposed at a predetermined position in front. A second light distribution pattern P2 (see FIG. 41) wide in the left-right direction extending from the vicinity of the right end of P1 to the left side of the left end is formed.

  The third lens body 12C is disposed in a posture in which the optical axis AX3 is further inclined outward with respect to the reference axis AX0 (14 ° is illustrated in FIG. 40). The incident surface 12a, the reflecting surfaces 12b and 12c, and the exit surface 12d of the third lens body 12C have a second light distribution pattern on a vertical screen in which light from the LED light source 11 incident on the lens is disposed at a predetermined position in front. A third light distribution pattern P3 (see FIG. 41) that is wide in the left-right direction extending from the right side of the right end of P2 to the left side of the left end is formed.

  The fourth lens body 12D is arranged in a posture in which the optical axis AX4 is further inclined outward with respect to the reference axis AX0 (21 ° is exemplified in FIG. 40). The fourth lens body 12D has an incidence surface 12a, both side reflection surfaces 12b and 12c, and an emission surface 12d. The third light distribution pattern is formed on a vertical screen in which light from the LED light source 11 incident on the lens is disposed at a predetermined position in front. A fourth light distribution pattern P4 (see FIG. 41) wide in the left-right direction extending from the vicinity of the right end of P3 to the left side of the left end is formed.

  Each of the light distribution patterns P1 to P4 is superimposed on the vertical screen, and a combined light distribution pattern that is wide in the horizontal direction in a gradation shape in which the light intensity decreases toward the outside (super-wide light distribution; see FIGS. 41 and 46). The optical axes of the headlamp units 10A to 10B are adjusted so as to be formed.

[Comparative example]
Hereinafter, regarding the superiority of the headlamp 100 of this embodiment (using the LED light source 11 having a correlated color temperature of 6000 [K] and a luminous flux of 1100 [lm]), a conventional LED headlamp (correlated color temperature: 4300) is used. [K], luminous flux: 540 [lm], hereinafter referred to as Conventional Example 1, and conventional HID headlamp (correlated color temperature: 4100 [K], luminous flux: 1100 [lm], hereinafter referred to as Conventional Example 2). A description will be given while comparing.

  FIG. 46 shows a light distribution pattern (luminance distribution) formed on the vertical screen by the headlamp 100 of the present embodiment. FIG. 47 is a light distribution pattern (luminance distribution) formed on the vertical screen by the headlamp of Conventional Example 1. FIG. 48 is a road surface light distribution pattern (isoluminance distribution) formed on the road by the headlamp 100 of the present embodiment. FIG. 49 is a road surface light distribution pattern (isoluminance distribution) formed on the road by the headlamp of Conventional Example 1. FIG. 50 shows a road surface light distribution pattern (isoluminance distribution) formed on the road by the headlamp of Conventional Example 2.

  46 to 50, according to the headlamp 100 of the present embodiment, the headlamps 100 arranged on the left side by the action of the lens bodies 12A to 12D are the headlamps of the conventional example 1 and the conventional example 2. Compared with the headlamps of Conventional Example 1 and Conventional Example 2, the ultra-wide light distribution (see FIGS. 41 and 46) that extends significantly to the left side as compared with the headlamps 100 arranged on the right side is larger on the right side. It can be seen that it forms an extended ultra-wide light distribution).

  According to the headlamp 100 of the present embodiment, the LED light source 11 that satisfies the above-described visibility for improving the visibility (perception) of the peripheral vision is used, and the light from the LED light source 11 is excessive. Considering the formation of a wide light distribution (FIGS. 41 and 46), not only the front visibility is improved, but also the left side (and the right side) as viewed from the periphery as compared with the headlamps of Conventional Example 1 and Conventional Example 2. It can be seen that the visibility (awareness) of is greatly improved.

  In addition, according to the headlamp 100 of the present embodiment, the ultra-wide light distribution is a gradation-shaped light distribution in which the light intensity decreases toward the outside (see FIGS. 41 and 46), so the left side (and the right side) in peripheral view It is clear that glare for pedestrians can be prevented or reduced while improving the visibility of Note that a light source having a high ratio of radiant energy components is less likely to reduce the reaction time even when the luminance is low (see FIGS. 42 to 45).

[Evaluation of ease of running]
In order to evaluate the ease of running of the vehicle equipped with the headlamp 100 of the present embodiment, the headlamps of Conventional Example 1 and Conventional Example 2, the following experiment was performed.

  Experimental environment: A vehicle equipped with the headlamp 100 of the present embodiment, the headlamps of Conventional Example 1 and Conventional Example 2 was used.

  Experimental procedure: Actually running on a vehicle equipped with the headlamp 100 of the present embodiment, the headlamps of the conventional examples 1 and 2, and the subjective evaluation scale (1: difficult to run, 2: difficult to run, 3: normal) (4: easy to run, 5: very easy to run). There are 18 subjects.

  FIG. 51 is a graph summarizing the evaluation results of ease of running. Referring to FIG. 51, it can be seen that the evaluation value of the headlamp 100 of this embodiment is the highest. This is presumably due to the fact that the headlamp 100 of this embodiment employs an ultra-wide light distribution that extends greatly to the left (and right).

  The headlamp 100 of this embodiment has an evaluation value as high as 0.8 as compared with the headlamp of Conventional Example 2 having substantially the same luminous flux. This is mainly because the color appearance under the illumination of the LED is closer to the color appearance under the illumination of the standard light source as compared with the HID (that is, the color can be reproduced more faithfully, see FIG. 37). This is thought to be due to the fact that an ultra-wide light distribution that extends greatly to the left (and right) is employed.

  The headlamp of Conventional Example 1 is one point lower in evaluation value than the headlamp of Conventional Example 2. This is probably because the headlamp of Conventional Example 1 has a lower luminous flux (540 [lm]) than the headlamp of Conventional Example 2 (light flux: 1100 [lm]), and therefore, the light distribution is less spread. .

[Evaluation of color visibility]
The following experiment was conducted in order to evaluate the visibility of the color when the vehicle equipped with the headlamp 100 of the present embodiment, the headlamps of the conventional example 1 and the conventional example 2 is running.

  Experimental environment: A vehicle equipped with the headlamp 100 of the present embodiment, the headlamps of Conventional Example 1 and Conventional Example 2 was used. On the road shoulder, red, green, blue, and yellow color marks C1 are arranged (see FIG. 52).

  Experimental procedure: Actually running on a vehicle equipped with the headlamp 100 of the present embodiment, the headlamps of the conventional examples 1 and 2, and the subjective evaluation scale (1: invisible, 2: dull, 3: normal, 4: slightly vivid, 5: very vivid) was used to evaluate the visibility of the color mark C1. There are 18 subjects.

  FIG. 53 is a graph summarizing the evaluation results of the visibility of colors during travel. Referring to FIG. 53, it can be seen that the evaluation value of the headlamp 100 of the present embodiment is highest for any of red, green, blue, and yellow. This is considered to be a result of color discrimination and vivid appearance due to the color temperature (6000 [K]) of the LED light source 11 used in the headlamp 100 of the present embodiment.

  Referring to FIG. 53, the headlamp 100 of the present embodiment greatly exceeds the evaluation values of the headlamps of Conventional Example 1 and Conventional Example 2, and can be said to be excellent in perception of signs. The red color meaning prohibition or regulation is 1.9 (70%) higher than the headlamp of Conventional Example 2 and 2.1 (84%) higher than the headlamp of Conventional Example 1. The yellow color meaning “attention” is 1.7 (59%) higher than the headlamp of Conventional Example 2 and 1.9 (77%) higher than the headlamp of Conventional Example 1. In view of this, according to the headlamp 100 of the present embodiment, not only the visibility (awareness) of peripheral vision can be improved, but also the visibility in terms of color perception can be improved. Can be estimated.

[Evaluation in the scene when turning right at the intersection]
The following experiment was conducted to evaluate the visibility of color in a scene when turning right at an intersection of a vehicle equipped with the headlamp 100 of the present embodiment, the headlamps of the conventional example 1 and the conventional example 2.

  Experimental environment: A vehicle equipped with the headlamp 100 of the present embodiment, the headlamps of Conventional Examples 1 and 2 was stopped before the intersection (see FIG. 54A). Color markers C2 (red, green, blue, and yellow) are arranged around the intersection (see FIGS. 54A and 54B).

  Experimental procedure: A subjective evaluation scale (1: invisible, 2: dull, 3: normal, 4: slightly vivid, 5: very vivid) was used to evaluate the visibility of color in the scene when turning right at the intersection. . There are 18 subjects.

  FIG. 55 is a graph summarizing the evaluation results of the visibility of colors in a scene when turning right at an intersection. Referring to FIG. 55, it can be seen that the evaluation value of the headlamp 100 of the present embodiment is the highest for any of the front of the pedestrian crossing, the center of the pedestrian crossing, the back of the pedestrian crossing, and the front of the shoulder.

  The headlamp 100 of this embodiment has a higher evaluation score of 3 in front of the pedestrian crossing than the headlamps of the conventional examples 1 and 2. This is mainly because the headlamp 100 arranged on the right side forms an ultra-wide light distribution that extends significantly to the right side compared to the headlamps of the conventional example 1 and the conventional example 2, and the visibility by the above-described peripheral vision. It is considered that the LED light source 11 that satisfies the condition for improving (awareness) is used, and that light from the LED light source 11 forms an ultra-wide light distribution. This is considered to have a great effect on the reduction of the accident involving a right turn. Further, the headlamp 100 of the present embodiment is superior to the headlamps of the conventional example 1 and the conventional example 2 because the evaluation points at the center of the pedestrian crossing and the depth of the pedestrian crossing are higher by 1.5 or more. I can guess.

As described above, according to the vehicle headlamp 100 of the present embodiment, the LED light source 11 that satisfies the condition for improving the visibility (awareness) in the peripheral vision described above, that is, the color temperature is 4500. 7000 [K] (preferably 5000 to 6000 [K]) and four coordinate values representing the prediction of the appearance of four colors (red, green, blue, yellow) correspond to the CIE1976L * a * b * space A ^* -b ^* coordinate value on the coordinate system R (41.7,20.9), G (-39.5,14.3), B (8.8, -29.9), Y (-10.4,74.2) circle with radius 5 Since the LED light source 11 included in the range is used, it is possible to improve the visibility (awareness) of surrounding pedestrians and obstacles in the actual traffic environment (especially when turning right at the intersection).

  The above embodiment is merely an example in all respects. The present invention is not construed as being limited to these descriptions. The present invention can be implemented in various other forms without departing from the spirit or main features thereof.

  DESCRIPTION OF SYMBOLS 100 ... Headlamp, 10A-10B ... Headlamp unit, 11 ... LED light source, 12A-12D ... Lens body, 13 ... Heat sink

Claims (2)

In a vehicle headlamp configured to emit light in a predetermined white range,
The vehicle headlamp includes a plurality of headlamp units including a first headlamp unit and a second headlamp unit,
The first headlamp unit includes a first LED light source, and a first lens body including an incident surface and an output surface on which light emitted from the first LED light source is incident,
The second headlamp unit has a second LED light source and an incident surface and an exit surface on which light emitted from the second LED light source is incident, and is adjacent to the first lens body. It has a lens body,
The first LED light source and the second LED light source have a color temperature of 4500 to 7000 [K] and are visible when four color (red, green, blue, and yellow) color charts are irradiated. The four coordinate values (a *, b *) representing the prediction of the coordinate system are coordinate values R (on the coordinate system with the vertical axis corresponding to the CIE1976L * a * b * space as the a * axis and the horizontal axis as the b * axis. 41.7,20.9), G (-39.5,14.3), B (8.8, -29.9), Y (-10.4,74.2)
The light emitted from the first headlamp unit forms a first light distribution pattern on a vertical screen disposed at a predetermined position in the irradiation direction,
The light emitted from the second headlamp unit forms a second light distribution pattern on the vertical screen;
Wherein Ri wide light distribution pattern der in the vehicle traveling direction outer side than the second light distribution pattern is the first light distribution pattern,
The second LED light source may be a white LED light source including a blue or ultraviolet light emitting LED element and a wavelength conversion material, or an LED light source combining LEDs of three colors of red, green, and blue, on xy chromaticity coordinates. A vehicle head characterized by irradiating white light in a chromaticity range surrounded by a straight line connecting (0.323, 0.352), (0.325, 0.316), (0.343, 0.331), (0.368, 0.379) lamp. 2. The vehicle headlamp according to claim 1, wherein the ratio of the amount of radiant energy existing at a wavelength of 450 to 550 nm to the amount of radiant energy present in the visible light region of the light source is higher than that of the halogen lamp light source.