JPH04300305A - Sun visor - Google Patents

Abstract

PURPOSE:To prevent the lowering of the visibility for targets caused by the rapid change in the brightness of a visual field by the driver of an auto-bicycle or car. CONSTITUTION:An equivalent light film brightness caused in the eye of a driver by a brightness distribution in a visual field is measured with an equivalent light film brightness measuring member 1, and outputted into an amplifying.controlling member 2. A signal for changing the transmittance of a transmittance-changing element in response to the magnitude of the amplified signal is outputted into a transmittance-changing light-transmitting member 3 to control the transmittance of the transmittance-changing element, thereby permitting to keep an equivalent light film brightness value instantaneously caused in the eye of the driver at a constant value or lover, and to prevent the driver from sensing the glaze of a highly bright article (or light source) and the visibility of the driver for an target from lowering.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sun visor for drivers of motorcycles and automobiles to prevent a decrease in visibility of objects caused by sudden changes in brightness within the field of view.

0002

[Prior Art] Conventionally, when performing electric welding, in order to prevent instantaneous sparks from causing glare or making it difficult to see the object to be welded, optical signals caused by sparks are detected and Based on this, it is known that the transmittance of safety glasses for workers is changed. Similar safety glasses are also available for people who work with laser light.

0003

However, these safety glasses are not designed to control the amount of transmitted light in consideration of the luminance distribution within the visual field or the adaptation state of the retina. Therefore, it can be said that these conventional safety glasses do not fully meet the demand.

SUMMARY OF THE INVENTION The present invention has been made in consideration of the problems of conventional safety glasses, and an object of the present invention is to provide a sun visor that can control the amount of transmitted light sufficiently effectively.

[0005]

[Means for Solving the Problems] The present invention provides a measurement equivalent light screen brightness measuring means for measuring equivalent light screen brightness, a transmittance variable transmission means having variable transmittance, and a signal from the equivalent light screen brightness measuring means. This sun visor is equipped with an amplification/control means that controls the transmittance of the variable transmittance transmitting means based on the above, and a casing that holds these together.

Further, the present invention further includes a foveal adaptation brightness measurement means for measuring retinal adaptation brightness, and includes an amplification and
The control means is a sun visor that is controlled based on the value of retinal adaptation brightness from the foveal adaptation brightness measurement means.

[0007]

[Effect] When a driver of a motorcycle or car is operating a vehicle outdoors in bright light, direct sunlight enters the driver's field of view and not only causes glare, but also makes it difficult to see objects in front of the driver.

[0008] Furthermore, at night, high brightness light from the headlights of an oncoming vehicle enters the driver's eyes, making it difficult to see objects in front of the driver, or sometimes making them almost impossible to see. This phenomenon occurs when there is a highly bright object within the visual field.The light from these bright objects (or light sources) enters the eyeball and is scattered, resulting in a light curtain that reduces the eye's sensitivity to light. get up to do The extent of the light curtain in this case is generally expressed quantitatively by the value of equivalent light curtain brightness.

Therefore, in the present invention, the value of the equivalent light screen brightness produced in the driver's eyes due to direct sunlight, etc. is measured by the equivalent light screen brightness measuring means, and the value from the equivalent light screen brightness measuring means is measured by the amplification/control means. The transmittance of the variable transmittance transmitting means is controlled based on the signal. This can prevent objects from becoming difficult to see with the driver's eyes.

[0010] Furthermore, when a plurality of short road tunnels exist in succession, the brightness of the visual field of a driver passing through this road during the daytime suddenly darkens or brightens, and the driver is unable to see objects in front of him. It may be difficult to see or glare may become a problem.

[0011] As in the case of the above-mentioned example, this phenomenon occurs mainly due to the brightness of the light screen produced in the driver's eyes by a highly bright object (or light source). In order to prevent such a phenomenon, the equivalent light curtain brightness at the driver's eye position may be controlled. However, when a driver enters a tunnel, the adaptation state of the retina of the driver's eyes changes over time after entering the tunnel, so this effect must be taken into consideration.

Therefore, in the present invention, the adaptation luminance of the retina is approximately measured by the foveal adaptation luminance measuring means, and the amplification and
The control means instantaneously controls the transmittance based on this value and the measured value of the equivalent light screen luminance, thereby preventing the driver from making it difficult to see the object.

[0013]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings.

First, a specific example of a sun visor intended to be used under conditions where the state of retinal adaptation of the driver's eyes can be treated as approximately constant, such as when driving a vehicle in bright daytime, will be described. In the first place, the ability of humans to visually recognize objects in a certain light environment (sensitivity state) is generally determined by the ability to discern differences in brightness (sensitivity state).
Luminance difference discrimination threshold) is expressed as ΔL. This luminance difference discrimination threshold △
L is determined by the brightness Laf to which the retina is adapted and the equivalent light curtain brightness Leq determined by the brightness distribution within the visual field.

[0015] The brightness to which the retina of the eye of a driver of a car driving in bright outdoors is adapted is Laf, which is strictly determined by the brightness distribution within the visual field and its temporal change, but is approximately the average brightness within the visual field. and in many cases can be treated as almost constant from an engineering perspective.

On the other hand, the equivalent light screen luminance L produced in the driver's eyes
eq is determined by the luminance distribution of the visual field at any given time. Therefore, in order to prevent the bright light from the sun from entering your eyes during the day, or the light from the headlights of an oncoming vehicle from entering your eyes at night, making it difficult to see objects, it is important to A device that measures the equivalent light screen brightness is installed near the person's eyes (for example, on the entire head), and based on this measurement value, the value of the equivalent light screen brightness produced in the eyes is kept below a certain value. Bye. For this purpose, a material (such as PLZT) whose transmittance can be changed instantaneously depending on the input signal is used for eyeglass lenses (
or a part thereof), and the equivalent rate of the glasses may be controlled by the value of the equivalent light curtain brightness.

FIG. 1 is a block diagram of the present invention constructed based on this idea. In the figure, reference numeral 1 denotes an equivalent light curtain brightness measurement unit that measures equivalent light curtain brightness, 3 a variable transmittance transmissive unit incorporating a variable transmittance element with variable transmittance, and 2
is an amplification/control unit that amplifies the signal from the equivalent light screen brightness measurement unit 1 and sends it as a control signal to the variable transmittance element of the variable transmittance light transmission unit 3. As the variable transmittance element of the variable transmittance transparent section 3, for example, PLZT is used.

Further, the equivalent light screen brightness measuring section 1, the amplification/control section 2, and the variable transmittance section 3 are fixed to a housing 4 of the helmet, as shown in FIG. In this case, it is desirable that the optical axis of the optical system of the equivalent light curtain brightness measuring section 1 is made to coincide with the line-of-sight direction as much as possible. It is technically possible to match the axes. In general-purpose sun visors, this is not done, and the equivalent light is measured so that the optical axis of the equivalent light curtain brightness measuring section 1 matches the line of sight when the driver is sitting upright and looking straight ahead. From the viewpoint of cost, it is desirable to fix the curtain brightness measuring section 1 to the housing 4.

When the driver wears this sun visor on his head and drives, the equivalent light screen brightness measuring section 1 can measure the equivalent light screen brightness Leq that occurs in the driver's eyes based on the brightness distribution within the field of view, and this output is The transmittance variable element (PLZT) of the transmittance variable transmissive section 3 is sent to the amplification/control section 2 and amplified, and the transmittance variable element (PLZT
) is sent to the translucent part 3, which momentarily lowers the equivalent light curtain luminance value that appears in the driver's eyes, thereby reducing the driver's feeling of being dazzled by a high-luminance object (or light source). This prevents the visibility of objects ahead from being obstructed.

By the way, the retinal adaptation brightness of the driver's eyes is different when driving in bright daytime and when driving on a dark road at night. For example, at night, the adaptation brightness is low and the sensitivity of the eyes to light is increased. Therefore, it is necessary to impose stricter restrictions on the equivalent light curtain brightness. Therefore, it is desirable that the amplification degree of the amplification/control unit 2 be lower than that during the daytime. If an amplification degree adjustment knob for this purpose is added to the amplification/control section 2 so that the amplification degree can be changed between night and day, the usable range can be expanded.

Next, a specific example of a sun visor that can be used even under conditions where the retinal adaptation brightness of the driver's eyes cannot be treated as constant, such as when driving on a road with a plurality of consecutive tunnels, will be described. That is, when driving on a road with a plurality of consecutive tunnels, temporal changes in the adaptation brightness (foveal adaptation brightness) Laf of the retina of the driver's eyes cannot be ignored. In such cases, the average brightness of the driver's visual field is measured, and the adaptive brightness La of the retina of the driver's eyes is calculated.
It is desirable to find f and use this value to adjust the magnitude of the input signal to the transmittance variable element that controls the equivalent light screen brightness Leq.

Specifically, when a driver enters a tunnel, the adaptive brightness Laf of the retina decreases over time. For example, immediately after passing through a 50 m long tunnel, and after passing through a 500 m long tunnel, Since the retinal adaptation luminance is lower in the latter case (i.e., the retina is more sensitive), the transmission is better immediately after passing through a 500 m long tunnel than immediately after passing through a 50 m long tunnel. The input signal to the variable rate element may be adjusted so as to suppress the transmittance of the element.

FIG. 3 is a block diagram showing the configuration of an embodiment for this purpose. The configuration is basically similar to that shown in FIG. 1, but a foveal adaptation brightness measurement unit 5 is added thereto for measuring the brightness (foveal adaptation brightness) Laf to which the retina of the driver's eye is adapted. is added. This foveal adaptation brightness measurement unit 5 is, for example, JP-A-59-206723, JP-A-6
This can be achieved by using a known measuring method such as that shown in No. 0-122330. As an actual sun visor, Figure 2
This foveal adaptation brightness measuring section 5 may be placed in the vicinity of the mounting position of the equivalent light screen brightness measuring section 1 of the sun visor shown in FIG. Note that the optical axis of the optical system of the foveal adaptation brightness measuring section 5 is made to coincide with the optical axis of the optical system of the equivalent light curtain brightness measuring section 1. The method of setting these optical axes is the same as that described in the method of setting the optical axis of the equivalent light curtain brightness measuring section 1 in FIG.

In the sun visor configured as shown in FIG. 3, the foveal adaptation luminance measuring section 5 measures the retinal adaptation luminance Laf (corresponding to the sensitivity state of the eye to light), and based on this value, the amplification/control section 2 controls the amplification. It is designed to adjust the degree. When the value of the retinal adaptation brightness Laf is high, the sensitivity state of the eye to light is low and the tolerance to the equivalent light screen brightness is also high, so the amplification degree of the amplifier in the amplification/control unit 2 is lowered, and vice versa. When the value of the retinal adaptation brightness Laf is low, the amplification degree of the amplification/control unit 2 is increased. In this case, the amplification degree control is based on the equivalent light curtain brightness Leq and the retinal adaptation brightness Laf.
and the luminance difference discrimination threshold ΔL (Yoshimura et al.,
“Effect of luminance of peripheral vision on luminance difference discrimination threshold in central vision” Journal of the Illumination Society of Japan 62, 729 (1978) K. K. Narisada etal: Lu
minance d'adaptation des
yeuxd'un conducteur a l'e
ntree d'untunnel nne meth
ode objective de measure. L
ux. No. 95, 348 (1977))).

[0025]

[Effects of the Invention] As explained above, by using the sun visor of the present invention, the equivalent light screen luminance generated on the driver's eyes by high-intensity objects (or light sources) such as direct sunlight and the headlights of oncoming vehicles can be reduced. It is possible to prevent the user from experiencing strong glare or from having difficulty seeing objects.

[0026] Furthermore, we have developed a sun visor that can sufficiently prevent glare even under conditions where the retinal adaptation brightness of the driver's eyes cannot be treated as constant, such as when driving on a road with multiple tunnels in succession. Can be provided.

[Brief explanation of drawings]

FIG. 1 is a basic configuration diagram of a sun visor according to an embodiment of the present invention.

FIG. 2 is a perspective view showing the same embodiment of the present invention.

FIG. 3 is a configuration diagram showing another embodiment of the present invention.

[Explanation of symbols]

1 Equivalent light screen brightness measurement unit (means) 2
, 21 Amplification/control unit (means) 3
Variable transmittance transparent section (means) 4
housing

Claims (3)

[Claims] 1. Measurement equivalent light curtain brightness measuring means for measuring equivalent light curtain brightness; transmittance variable transmission means having variable transmittance; A sun visor comprising: amplification/control means for controlling the transmittance of the variable transmission means; and a casing that holds these together. 2. A foveal adaptation brightness measurement means for measuring retinal adaptation brightness, wherein the amplification/control means performs control based on the value of the retinal adaptation brightness from the foveal adaptation brightness measurement means. A sun visor according to claim 1, characterized in that: 3. The sun visor according to claim 1, further comprising an adjustment knob for manually changing the degree of amplification of the amplification/control means.