JPH0330525B2 - - Google Patents

Description

[Detailed Description of the Invention] <<Industrial Application Field>> The present invention is a method for preventing dazzling caused by the headlights of an oncoming vehicle without impairing the forward visibility of the vehicle, for example, when the vehicle is running at night. Regarding prevention devices.

《Prior art and its problems》 As a conventional anti-dazzle device, for example,
- As seen in Japanese Patent Publication No. 101526, a polarizing plate is used to block the headlight light of an oncoming vehicle, or as seen in Japanese Patent Application Laid-Open No. 49-72830 and Japanese Patent Application Laid-open No. 138526-1989. As shown in Figure 3, there are known vehicles that use a liquid crystal panel to block the headlights of oncoming vehicles.

However, such conventional anti-dazzle devices have the disadvantage that, for example, those that use polarizing plates are not effective unless all vehicles are equipped with polarizing plates, and those that use liquid crystal panels In such cases, when the headlights of an oncoming vehicle are blocked, the entire field of vision in front of the vehicle becomes dark, and there is a risk that the driver may misjudge road irregularities or obstacles (pedestrians, etc.) that should be visible. be.

[Object of the Invention] An object of the present invention is to provide an anti-dazzling device that can prevent dazzling caused by the headlights of an oncoming vehicle without impairing forward visibility of the own vehicle when applied to a vehicle running at night, for example. There is a particular thing.

<<Structure of the Invention>> The present invention provides a light projecting means that repeats irradiation with a predetermined amount of light toward a predetermined monitoring area and stopping the irradiation with the predetermined amount of light at a cycle that appears to be a constant amount of light to the human eye. and is placed between a supervisor who monitors the monitoring area and the monitoring area, and has a predetermined transmittance during a period when irradiation with the predetermined amount of light is performed, and when irradiation with the predetermined amount of light is stopped. and a variable transmittance filter that has a transmittance lower than the predetermined transmittance during a certain period.

<<Description of Embodiments>> First, the operating principle of the present invention will be explained. When examining human visual characteristics, as shown in Figure 1, irradiation with a predetermined amount of light is turned on, irradiation with a predetermined amount of light is turned off, and the light is turned on in long cycles.
When turned off (blinking), it appears flickering to humans. However, if you shorten this ON/OFF cycle, the flickering will eventually disappear and it will begin to appear as a constant light.

Furthermore, the sense of brightness at this time is equal to the sense of brightness felt when viewing stationary light equal to the average value I' of the light intensity I, as shown by the broken line in FIG.
This is called Talbot's law.

In other words, even if a strong light I (for example, equivalent to the headlight of a car) is emitted, if the light is blinked to the extent that it does not flicker, the human eye will see the light I', which is weaker than the light intensity I. It just feels like it's being emitted on a regular basis.

In addition, the light intensity I' that humans perceive, indicated by the broken line in Figure 1, can be considered to be the average value of the actual light intensity I, that is, the integrated value per unit time, so the light intensity I' is considered to be an integrated value per unit time. It can be seen that the shorter is the instantaneous light intensity I, the greater the instantaneous light intensity I can be.

The present invention utilizes this Talbot's law.

That is, a variable transmittance filter is constructed using a transparent glass plate filled with liquid crystal or the like, and is placed in front of the observer (for example, a vehicle driver). By intermittently applying a voltage to the liquid crystal electrode constituting the variable transmittance filter, the light coming from the outside and entering the observer's eyes is interrupted at high speed.

As a result, the dazzling light beam (for example, the light from the headlights of an oncoming vehicle) is perceived by the observer's eyes as a weak steady light, and the observer is no longer dazzled.

On the other hand, from the supervisor's side, visible light is intermittently irradiated from a floodlight (for example, the headlight of the own vehicle), and the variable transmittance filter is controlled to a high transmittance state only during the ON period of this intermittent light. .

As a result, the intermittent light (for example, the intermittent light from the headlight of the own vehicle) emitted from the projector to the monitoring area reaches the observer's eyes without being blocked by the variable transmittance filter.

If the brightness perceived by the observer's eyes when irradiated with intermittent light emitted from a floodlight is set to match the brightness of the constant light of current headlights in the case of a vehicle, for example, it would be possible to Objects that can be seen with the headlight can be seen with almost no effect.

Next, a concrete embodiment of the present invention using the following principle will be described with reference to FIGS. 2 to 5.

In this embodiment, the present invention is applied to the front monitoring of a vehicle.

In FIG. 2, a timing signal generation circuit 1 outputs a high-speed pulse train, and in response to this pulse train, a drive circuit 2 operates to drive floodlights 3a and 3b installed in place of the left and right headlights. Visible light is emitted from the projectors 3a and 3b toward the front of the vehicle while being interrupted at short intervals so that it appears to the human eye as a continuous light beam with a constant amount of light.

The details of the floodlights 3a and 3b are shown in Figures 3 and 4.
As shown in the figure, a motor 6 is fixed with its axis perpendicular to the inner bottom of a sealed housing 5, which has a lens 4 fitted into its front opening, and a parabolic mirror formed on the top of the axis. A reflector 7 is fixed and supported so as to be rotatable around the vertical axis of the motor 6, and a light bulb 8 serving as a light source is suspended and fixed at the focal point of the reflector 7, thereby causing the motor 6 to rotate at high speed. And each time the lens 4 is positioned in front of the reflector 7 in the reflection direction,
When the front of the vehicle is irradiated with a predetermined amount of visible light, and the front reflection direction of the reflector 7 faces in a direction other than the lens 4, the front of the vehicle is not irradiated with visible light and the predetermined amount of light is irradiated. It is configured so that it is stopped.

Next, in FIG. 2, the high-speed pulse train output from the timing signal generation circuit 1 is transmitted to the frequency dividing circuit 9
The frequency is divided by an appropriate frequency division ratio.

The drive circuit 10 operates a variable transmittance filter plate 1 based on the pulse train output from the frequency dividing circuit 9.
Drive 1. Then, the filter plate 11 is illuminated with visible light from the floodlights 3a and 3b.
OFF, in which the transmittance is controlled to a predetermined level (hereinafter referred to as a high transmittance state) only in synchronization with the period, and visible light is cut off from the projectors 3a and 3b.
Regarding the period, the transmittance is lower than the transmittance in the high transmittance state (hereinafter, this state is referred to as the low transmittance state).
controlled.

The specific structure of the filter plate 11 is as shown in FIG. 5, as shown in FIG.
A window frame-shaped spacer 14 is interposed between two glass plates 13a and 13b formed by forming glass plates a and 12b into planar shapes, and a field-effect nematic liquid crystal is sealed in the internal space formed by this spacer 14. By intermittently applying a predetermined voltage between lead wires 15a and 15b drawn out from each transparent electrode 12a and 12b, the light transmittance can be changed to a high transmittance state and a low transmittance state. The rate state can be controlled intermittently.

Further, in this example, the filter plate 11 is formed into a shape similar to that of a vehicle sun visor, as shown in FIGS. It is rotatably supported by a bracket 19 attached to the ceiling of the vehicle interior.

Therefore, like a vehicle sun visor, it can be pulled down and used in front of the driver as needed.

Next, to explain the operation, when the motor 6 rotates at high speed due to the output of the drive circuit 2, the projector 3
Visible light is intermittently irradiated from a and 3b toward the front of the vehicle. Here, the intermittent frequency of this intermittent light is set to, for example, about 500 Hz, so that the driver of the own vehicle and the driver of an oncoming vehicle may see the light source 3.
You will feel as if constant light is being irradiated from a and 3b.

On the other hand, as described above, the filter plate 11 enters a high transmittance state in synchronization with the ON period (period of irradiation with a predetermined amount of light) of the intermittent light generated from the projectors 3a and 3b, and the OFF period (period of irradiation with a predetermined amount of light) of the intermittent light generated from the projectors 3a and 3b. It is intermittently controlled to be in a low transmittance state in synchronization with the stop period).

Therefore, in the eyes of the vehicle driver, the floodlights 3a, 3
The light emitted from B is reflected by an object in front of the vehicle and directly passes through the filter plate 11, and the brightness perceived by the driver is approximately the same as the brightness of conventional headlights. becomes.

On the other hand, in this state, when the oncoming headlight arrives, the continuous light beam from this headlight is interrupted by the filter plate 11.
The driver's eyes will perceive this as an average light intensity obtained according to Talbot's law, and in other words, even if the headlights of an oncoming vehicle arrive with considerable intensity, there is no risk of the driver being dazzled by this light.

Therefore, according to the present invention, it is possible to prevent dazzling caused by the headlights of oncoming vehicles without impairing the forward visibility of the own vehicle.

Next, another embodiment of the apparatus of the present invention will be described with reference to FIGS. 8 and 9.

In FIG. 8, the timing signal generation circuit 20
outputs a high-speed pulse train.

The drive circuit 21 receives a pulse train from the timing signal generation circuit and drives the light projector 22 in synchronization with the pulse train, so that the light projector 22 emits an intermittent light beam in synchronization with the pulse train output from the timing signal generation circuit 20. .

On the other hand, the intermittent light emitted from the projector 22 is detected via the photodetector 23, the drive circuit 24 operates according to this detection output, and the filter plate 25 is synchronized with the ON period of the intermittent light beam from the projector 22. and is controlled to a high transmittance state, and is controlled to a low transmittance state in synchronization with the OFF period.

Next, the specific configuration of the light projector 22 will be explained based on FIG. 9.

Visible light emitted from a lamp 26 serving as a light source is focused by a reflector 27 made of a parabolic mirror, and then irradiated forward.

A variable transmittance filter plate 28 is interposed in front of the reflector 27 and is appropriately inclined with respect to the optical axis of the reflector 27 .

This filter plate 28 consists of two transparent glass plates 2
A piezoelectric body 30 is sandwiched between 9a and 29b to form a sandwich structure, and both transparent glass plates 29a and 29b
By supplying output pulses from the drive circuit 21 to the electrodes formed on the inner surface of the
The transmittance can be controlled intermittently.

Therefore, when the filter plate 28 is in a high transmittance state, the light from the reflector 27 passes through the filter plate 2.
8 as is and becomes the L light corresponding to the left headlight, which is transmitted through the lens 30b and the optical fiber 31.
b. Through the lens 32b of the left headlight,
When the filter plate 26 is in a low transmittance state, the light from the reflector 27 is reflected by the filter plate 28, and then the light is directed toward the front of the vehicle.
The light becomes light and is irradiated to the front of the vehicle via the lens 30a, the optical fiber 31a, and the lens 32a of the right headlight.

Therefore, the front of the vehicle is irradiated with visible light from the left and right headlights intermittently, and by shortening the intermittent period to the extent that it appears to the human eye as a continuous beam of light. It is designed to provide the same level of brightness as a conventional headlight.

On the other hand, the light emitted from the right lens 32a is
The light is detected by the photodetector 23, and in response to the detection output, the drive circuit 24 operates, and the transmittance of the filter plate disposed in front of the driver's vehicle changes intermittently.

According to this embodiment, as a means for irradiating the front of the vehicle with visible light intermittently at short intervals so that it appears as a continuous light beam to the human eye, a filter that can take either a transmission state or a reflection state is used. Since the plate is used, there is no need for moving parts as in the previous embodiment, making the structure of the projector simple and long-lasting.In addition, to obtain intermittent light, the light from one light source can be combined with the left and right lights. This also has the effect of making it possible to use the light from the light source more efficiently.

Next, FIG. 10 shows yet another example of a projector, in which optical fibers 35a are provided on four sides.
A parabolic mirror-like reflector 3 is installed in a sealed housing 33 in which the incident end surfaces of .
4 from the output end of each fiber.
I'm trying to get phase light pulses.

In addition, each optical fiber is 35a, two each.
The light is distributed to left and right headlight positions such as 35b, 35c, and 35d, and irradiated forward from the left and right headlight positions via lenses 36a to 36d.

In addition, photodetectors 37a and 37b are provided on the front side of each lens 36a and 36b on the right side, respectively.
The drive circuit 24 is operated by the output of these logical sums.

According to this embodiment, in addition to being able to effectively utilize the light from the light source, the intermittent light emitted from the left and right headlights has a phase difference of 90° from each other, so the rotation speed of the reflector does not need to be increased significantly. This has the effect that the human eye can easily obtain light close to continuous light.

In the above embodiments, a headlight of a vehicle is used as an example of a projector, but it goes without saying that an auxiliary lamp of a vehicle may be used as a projector.

Furthermore, although the light beam is applied intermittently in the embodiment described above, the same effect can be obtained by changing the illumination intensity in steps, for example.

<<Effects of the Invention>> As is clear from the description of the embodiments above, according to the present invention, when applied to a vehicle, for example, it is possible to reliably prevent dazzling caused by the headlights of an oncoming vehicle without impairing the forward visibility of the own vehicle. This effect can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a graph for explaining the principle of the present invention, Fig. 2 is a block diagram showing the electrical configuration of one embodiment of the invention, Fig. 3 is a side sectional view showing the structure of the projector, and Fig. 4 Figure 5 is an exploded perspective view showing the structure of the filter plate, Figure 6 is a perspective view showing the variable transmittance type filter plate attached to a vehicle, and Figure 7 is a perspective view of the filter plate. FIG. 8 is a block diagram showing the electrical configuration of another embodiment of the device of the present invention, FIG. 9 is a schematic diagram showing the configuration of a floodlight used in the same embodiment, and FIG. FIG. 10 is a schematic diagram showing another example of the projector. 3a, 3b...projector, 11...variable transmittance filter plate.

Claims (1)

[Scope of Claims] 1. Light projecting means that repeats irradiation with a predetermined amount of light toward a predetermined monitoring area and stopping the irradiation with the predetermined amount of light at a cycle that appears to be a constant amount of light to the human eye; The device is placed between a supervisor who monitors the monitoring area and the monitoring area, and has a predetermined transmittance during a period when irradiation with the predetermined amount of light is performed, and a period when irradiation with the predetermined amount of light is stopped. An anti-dazzle device comprising: a variable transmittance filter having a transmittance lower than the predetermined transmittance.