TWI388773B - Optical system with dual-illumination sources - Google Patents

Description

Light source sharing optical system

The present invention relates to a light source sharing optical system, and in particular, to a light source sharing optical system in which a visible light source and a near-infrared light source can simultaneously project light.

With the degree of industrial progress in the countries of the world, the number of vehicles used has also increased year by year, and of course, traffic accidents have also arisen. Therefore, the theme of vehicle safety has gradually received the attention and attention of the automobile manufacturing industry, consumers and governments. According to the survey data of the World Health Organization and the American Vehicle Insurance Company, the average annual global death and injury caused by traffic accidents exceeds 6 million, and the social cost is difficult to measure by money. In addition, if the number of people per 100,000 population is counted, the number of deaths per year in traffic accidents is 15 in the United States, 11 in Japan, and 26 in Taiwan. Among them, 55% of the fatal accidents occurred at night, and 62% of pedestrians died from night driving. Obviously, night traffic accidents have a very high fatality rate. In response to the above-mentioned nighttime traffic accidents, each manufacturer uses the car night vision device to assist the driver's vision, increasing nighttime visibility, and thus reducing accidents.

In the car night vision device, the image sensor of the CCD or CMOS circuit structure is combined with the semiconductor integrated circuit process and is made of a silicon wafer. The band gap energy of the germanium material is 1.1 electron volts (eV), so according to the photoelectric conversion theory, the light with a spectrum of electromagnetic waves of less than 1.1 μm is responsive. In addition, the lens of the lens is made of optical glass, and most of the optical glass has a good light transmittance when the electromagnetic spectrum is less than 1.1 μm. Therefore, by selecting the appropriate edge filter spectrum range specification, the optical lens and CCD/CMOS image sensor and image processing circuit can be used to design the near-infrared (0.8μm~1.1μm) dedicated or visible light. (0.3μm ~ 0.7μm) and the near-infrared band dual-use camera module. Although the development of this type of camera is quite mature, in the low illumination environment, the quality and resolution of the image will be adversely affected. Therefore, a near-infrared auxiliary illumination source must be added to improve the image resolution. This technology is applied to vehicle equipment, which can improve driving visibility in low-light environments and reduce night traffic accidents.

Because the retinal nerves of the human eye only respond to the visible light band, before the near-infrared image is applied to the vehicle safety-assisted driving, the traditional lamp illumination only projects the visible light source with reflective optical elements, or adds refractive optics. The component is modified for the lighting division/appearance configuration. When NIR photography technology began to be introduced into the field of vehicle safety-assisted driving, the near-infrared illumination optical system has not been greatly improved, and only the visible light band of the original wide spectrum (including visible light and near-infrared light) is shielded by a filter. And make the near-infrared light source penetrate. For example, U.S. Patent No. 7,331,690 B2, U.S. Patent 7,345,414 B1, all of which are incorporated herein by reference.

The above-described near-infrared light source projects the inventive device and cannot provide both visible and near-infrared light sources. In the invention of the Republic of China Patent Certificate No. I293357, an inventive device capable of simultaneously emitting visible light and near-infrared light is proposed. The invention utilizes a partial filter coating on the bulb such that a portion of the bulb provides visible light and a portion provides near-infrared light. Although the problem of simultaneous illumination of visible light and near-infrared light is improved, the use of such a shared light source is improved. The method also causes the illumination of the visible light and the near-infrared light source to be insufficient, or the illumination cannot be independently adjusted according to the illumination response requirements of the two-band sensor (human eye/camera).

In U.S. Patent No. 7,134,775 B2, two separate LED sources, a visible LED source and a near-infrared LED source, are projected using reflective optical elements. Because the positions of the visible LED source and the near-infrared LED source are different with respect to the reflective optical element, the angles at which the visible LED source and the near-infrared LED source are projected are different. However, the projection angles of the two different band illuminations are fixed, and the position adjustment of the high beam and low beam projections cannot be performed at any time as the driving road condition actually needs.

Further, in the above-mentioned shortcoming, in the invention of the Republic of China Patent Certificate No. M317958, a method and apparatus for improving the light source switching device of the lamp are proposed. However, it is limited to a single source of light for near and far projection distance switching, and because the baffle is used to shield part of the light, the originally illuminable light will be lost.

Therefore, the above lighting design still cannot meet the actual needs of driving.

One aspect of the present invention is to provide a light source sharing optical system using a combination of a visible light source, a near-infrared light source, a reflective element and a refractive element, which is applied to a vehicle safety aid by an optical system structure shared by visible light and near-infrared illumination sources. drive.

According to an embodiment of the present invention, a light source sharing optical system includes a visible light source, a set of near-infrared light sources, a first lens array, a second lens array, a parabolic mirror, a secondary mirror, a focusing lens, and a control Angle adjustment mechanism. The visible light source is disposed at the focal position of the parabolic mirror, so that the light diverged by the visible light source is reflected by the parabolic mirror to form parallel rays.

In addition, the visible light source is disposed between the parabolic mirror and the secondary mirror, so that the light emitted by the visible light source toward the secondary mirror is emitted at a solid angle of the hemispherical space toward the parabolic mirror after the reflection, and then reflected by the parabolic mirror. Then parallel rays are formed. A first lens array is disposed at an opening edge position of the parabolic mirror to focus the parallel light reflected by the parabolic mirror. The focal length of the first lens array positions the second lens array, so that the second lens array can function as a field lens to correct the angle of the off-axis beam. In combination with the Gaussian imaging formula and the need for a projection source, a focusing lens is disposed opposite the first lens array and the second lens array. Therefore, the visible light source can be projected onto the designed illumination position and illumination range as needed. A near infrared light emitting diode (NIR_LED) is disposed between the first lens array and the second lens array, and a light emitting surface of the NIR_LED faces the second lens array, so that light of the NIR_LED penetrates the second lens array and focuses The lens can then be designed according to the Gaussian imaging formula and the requirements of the projection source to design the optical specifications of the second lens array and the focusing lens, so that the light source of the NIR_LED is projected to the front lighting demand position.

In practice, NIR_LED can be soldered on a transparent acrylic plate or glass plate, and patterned with ITO coating, and because the volume of NIR_LED is small, it will not cover the visible light aperture area of visible light. Cause too much impact. In addition, since the light of the NIR_LED has nothing to do with the parabolic mirror, the control of the angle adjustment mechanism to change the optical axis orientation of the parabolic mirror only affects the direction of travel of the visible light source after being reflected by the parabolic mirror. The visible light source can then be separated from the projection direction of the near-infrared light source.

The advantages and spirit of the present invention will be further understood from the following detailed description of the invention.

The present invention relates to a light source sharing optical system using a visible light source, a near-infrared light source, a reflective element, and a refractive element. The light source sharing optical system can use a visible light illumination optical system to project a visible light source to a nearer place (low beam) in an under-illuminated weather condition, so that the vehicle can visually recognize the front scene. In addition, by sharing part of the optical path of the visible light illumination optical system described above, the near-infrared light source can be simultaneously projected to a greater distance (high beam) than the visible light source, so that the near-infrared camera mounted on the vehicle can also obtain sufficient The lighting conditions are used to display the distant image on the in-vehicle screen using image sensors and image processing circuits.

Please refer to Figure 1 and Figure 2. 1 is a schematic diagram showing a light source sharing optical system 1 according to an embodiment of the present invention, and FIG. 2 is a schematic diagram showing the application of the light source sharing optical system 1 of the vehicle 2 according to another embodiment of the present invention. . As shown in FIG. 1, the light source sharing optical system 1 includes a visible light source 11, a near-infrared light source 12, a first lens array 130, a second lens array 132, a parabolic mirror 14, a secondary mirror 15, a focusing lens 16, and an angle adjustment. The organization 17 is composed of. As shown in FIG. 2, the X-Z plane view may be referred to as a side view of the vehicle 2, and the Y-Z plane view may be referred to as a bird's eye view of the vehicle 2. In practice, the visible light source 11 may comprise a tungsten filament or a light emitting diode (white or other colored light) to emit visible light.

In the present embodiment, the visible light source 11 is disposed at the focal position of the parabolic mirror 14. Therefore, the light emitted by the visible light source 11 is reflected by the parabolic mirror 14 and becomes parallel light. In addition, the visible light source 11 is disposed between the parabolic mirror 14 and the secondary mirror 15 , so that the light emitted by the visible light source 11 toward the secondary mirror 15 is reflected by the secondary mirror 15 and then faces the parabolic mirror 14 . Hemispherical space solid angle launch. Then, the light reflected by the secondary mirror 15 is reflected by the parabolic mirror 14 and becomes parallel rays.

The first lens array 130 is disposed at an opening edge position of the parabolic mirror 14 that focuses the parallel light reflected by the parabolic mirror 14. The second lens array 132 can be disposed at a focal position of the first lens array 130. In practice, the second lens array 132 can function as a field lens to correct the angle of the off-axis beam. The focusing lens 16 can be disposed relative to the first lens array 130 and the second lens array 132, as shown in FIG. In practice, the position of the focusing lens 16 can be set according to the Gaussian imaging formula and the requirements of the projection source, so that the light emitted by the visible light source 11 can be projected onto the designed illumination position and illumination range as needed. The near-infrared light source 12 is disposed between the first lens array 130 and the second lens array 132, and causes the light-emitting surface of the near-infrared light source 12 to face the second lens array 132, so that the light emitted by the near-infrared light source 12 can penetrate The two lens array 132 and the focus lens 16. In practice, the optical specifications of the second lens array 132 and the focusing lens 16 can be set according to the Gaussian imaging formula and the requirements of the projection light source, thereby projecting the light source emitted by the near-infrared light source 12 to the front illumination demand position. In addition, the near-infrared light source 12 can be soldered on a transparent acrylic plate or a glass plate, and patterned with ITO coating, and because the volume of the near-infrared light source 12 is small, its light-passing aperture for visible light Area shading does not have much impact.

In the present embodiment, the angle adjustment mechanism 17 can be coupled to the parabolic mirror 14 for adjusting the deflection angle of the parabolic mirror 14. In addition, since the light emitted by the near-infrared light source 12 is not related to the parabolic mirror 14, the angle adjusting mechanism 17 can only change the optical axis orientation of the parabolic mirror 14 to affect the traveling direction of the visible light reflected by the parabolic mirror. Therefore, the visible light source is separated from the projection direction of the near-infrared light source.

Therefore, in practice, the light source sharing optical system uses a visible light illumination optical system to project a visible light source to a nearer place (low beam) in a weather condition with insufficient illumination, so that the vehicle can visually recognize the front scene with the naked eye. And sharing part of the optical path of the light source sharing optical system, the near-infrared light source can be simultaneously projected to a farther distance than the visible light source (high beam), so that the near-infrared camera sub-module mounted on the vehicle can also Obtain sufficient lighting conditions to display distant images on the in-vehicle screen using image sensors and image processing circuits. Therefore, the light source sharing optical system according to the present invention can simultaneously provide illumination of a near-infrared light source to a near-infrared camera in addition to the function of the automobile lamp as in the prior art to provide visible light illumination required for the vehicle to drive the naked eye. In practice, when a near-infrared camera is used to obtain a dangerous situation in a long-distance image driving (such as pedestrian crossing/animal roaming/unknown roadblocks), the light source sharing optical system can be adjusted (driving manual control/computer automatic control) visible light. The light projection angle of the source is used to change the low-light illumination state of the original visible light to the state of the high-beam illumination, so that the driving can directly detect the dangerous situation when the near-infrared photography system detects a dangerous situation at a long distance. The most favorable vehicle driving reaction action is made at the actual road conditions at the distance. The above-mentioned visible light illumination (low beam) does not interfere with the oncoming vehicle during the intersection of the vehicle, and can also provide more road information for driving the vehicle with near-infrared illumination (high beam), so it can effectively increase the warning time to prevent dangerous situations. .

To explain in detail the principle of illumination of the visible light source, the following is a further description of the basic physical concept of geometric optics in conjunction with Figures 3A through 4C. Please refer to FIG. 3A. FIG. 3A is a partial schematic view of the light source sharing optical system 1 of FIG. As shown in FIG. 3A, from the basic concept of geometric optics, the light emitted by the visible light source 11 from the focus 140 of the parabolic mirror 14 (the center point of the focal plane) can be reflected by the parabolic mirror 14 and parallelized. The direction of the optical axis of the parabolic mirror 14 is emitted in parallel. In addition, please refer to FIG. 3B, which is a partial schematic view of the light source sharing optical system 1 of FIG. As shown in Fig. 3B, it is also known from the basic concept of geometric optics that the light emitted from the off-axis position 142 of the visible light source 11 from the focal plane of the parabolic mirror 14 can be reflected by the parabolic mirror 14 and reflected by the paraboloid. The optical axis of the mirror 14 intersects at an oblique angle to emit another parallel beam. In addition, the light emitted by the visible light source 11 is also reflected by the secondary mirror 15. According to the position of the focal plane (center point or off-axis point) of the light passing through the parabolic mirror 14, it is known that the light is on the surface of the parabolic mirror. After reflection, the light is emitted in the direction of the parallel optical axis or the oblique optical axis.

In summary, the light emitted by the visible light source 11 on the focal plane of the parabolic mirror 14 is reflected by the parabolic mirror 14 to produce two kinds of emission; and the optical axis of the parabolic mirror 14 is the same. The parallel beams and the optical axis of the parabolic mirror 14 have parallel beams at oblique angles.

Please refer to FIG. 4A. FIG. 4A is a schematic diagram showing the visible light source 11 of FIG. 3A emitting light from the focus 140 of the parabolic mirror 14 . As shown in FIG. 4A, after the visible light source 11 is reflected by the parabolic mirror 14 from the light beam 140 of the parabolic mirror 14, only the first lens array 130 and the focusing lens 16 need to be disposed in front of the parabolic mirror 14, that is, The system requirements can be designed to project a beam of light at a specific distance for illumination. However, please refer to FIG. 4B. FIG. 4B is a schematic diagram showing the visible light source 11 of FIG. 3B emitting light from the off-axis position 142 on the focal plane of the parabolic mirror 14 . As shown in FIG. 4B, the light reflected by the parabolic mirror 14 is obliquely emitted, so that some of the light cannot fall within the aperture of the focus lens 16, and a vignetting phenomenon is formed. Halo phenomena will cause problems in light use efficiency and uneven illumination. In order to improve this disadvantage, the second lens array 132 can be further provided for use as a field lens, as shown in Fig. 4C. Thus, the light of the visible light source 11 can be projected to a desired distance.

In addition, in order to explain in detail the illumination principle of the near-infrared light source, the basic physical concept of geometric optics is further described in conjunction with FIG.

Please refer to FIG. 5 , which is a partial schematic diagram of the light source sharing optical system 1 of FIG. 1 . As shown in FIG. 5, the near-infrared light source 12 is disposed between the first lens array 130 and the second lens array 132, and the light-emitting surface of the near-infrared light source 12 faces the second lens array 132. The optical path of the near-infrared source 12 will only pass through the second lens array 132 and the focusing lens 16, so that the combination of both the second lens array 132 and the focusing lens 16 can be considered an equivalent focusing lens of the near-infrared source 12. Since the near-infrared light source 12 can use NIR_LED, its volume is very small, and can be soldered on a transparent glass plate, the near-infrared light source 12 does not shield the light emitted by the visible light source 11. In practice, the number of NIR_LEDs included in the near-infrared light source 12 can be arranged according to requirements such as luminous power and projection distance illumination, and is not limited to the specific embodiments listed in the present specification.

According to a specific embodiment of the present invention, in order to be able to separate the projection distance and position of the visible light and the near-infrared light, the angle adjustment mechanism 17 (shown in FIG. 1) can be utilized to make the parabolic mirror 14 oppose the XZ plane. The apex 144 of the parabolic mirror 14 is angularly rotated to change the angle between its optical axis and the X and Z axes. Please refer to FIG. 6A and FIG. 6B. FIG. 6A and FIG. 6B are partial schematic views showing the angle adjustment mechanism 17 of the light source sharing optical system 1 of FIG. 1 adjusting the angle of the parabolic mirror 14. As shown in FIG. 6A, when the angle adjusting mechanism 17 makes the optical axis of the parabolic mirror 14 at an angle of 0° with respect to the Z axis, the filament of the visible light source 11 can be regarded as the focal plane of the parabolic mirror 14 in the XZ plane view. The point source on the center (focus 140), at this time, the visible light emitted by the visible light source 11 is emitted in parallel with the Z-axis direction. As shown in FIG. 6B, when the angle adjusting mechanism 17 makes the angle between the optical axis of the parabolic mirror and the Z axis not zero, the visible light emitted by the visible light source 11 is emitted as a parallel beam in the oblique Z-axis direction. Therefore, the projection angle of visible light can be achieved by an angular adjustment mechanism that causes the parabolic mirror to rotate angularly.

In practice, the parabolic mirror of the light source sharing optical system can be replaced by an elliptical mirror. Therefore, the visible light emitted by the visible light source disposed on the elliptical mirror can be concentrated to another focus of the elliptical mirror. The reflected visible light is then emitted by the first lens array, the second lens array, and the focus lens. In other words, the light source sharing optical system can reflect the visible light emitted by the visible light source by the concave mirror, and is not limited to the parabolic mirror.

In addition, the focusing lens of the above-mentioned light source sharing optical system can also be replaced by a focusing mirror as long as the light can be focused to the place to be illuminated. In other words, the light source sharing optical system can focus the visible or near-infrared light to the intended illumination without being limited to the focus lens.

The features and spirit of the present invention will be more apparent from the detailed description of the preferred embodiments. On the contrary, the intention is to cover various modifications and equivalents within the scope of the invention as claimed. Therefore, the scope of the patented scope of the invention should be construed as broadly construed in the

1. . . Light source sharing optical system

11. . . Visible light source

12. . . Near infrared source

130. . . First lens array

132. . . Second lens array

14. . . Parabolic mirror

15. . . Secondary mirror

16. . . Focusing lens

17. . . Angle adjustment mechanism

140. . . focus

142. . . Off-axis position

144. . . vertex

2. . . vehicle

1 is a schematic view showing a light source sharing optical system according to an embodiment of the present invention.

2 is a schematic diagram of a light source sharing optical system of the vehicle application diagram 1 according to another embodiment of the present invention.

FIG. 3A is a partial schematic view showing the light source sharing optical system of FIG. 1.

FIG. 3B is a partial schematic view showing the light source sharing optical system of FIG. 1.

FIG. 4A is a schematic diagram showing the visible light emitted from the focus of the parabolic mirror of FIG. 3A.

FIG. 4B is a schematic view showing that the visible light of FIG. 3B is emitted from the off-axis position on the focal plane of the parabolic mirror.

FIG. 4C is a schematic diagram showing that the visible light of FIG. 3B is derived from the off-axis position on the focal plane of the parabolic mirror and emits light through the first lens array and the second lens array.

Figure 5 is a partial schematic view showing the light source sharing optical system of Figure 1.

6A and FIG. 6B are partial schematic views showing the angle adjustment mechanism of the light source sharing optical system of FIG. 1 for adjusting the angle of the parabolic mirror.

1. . . Light source sharing optical system

11. . . Visible light source

12. . . Near infrared source

130. . . First lens array

132. . . Second lens array

14. . . Parabolic mirror

15. . . Secondary mirror

16. . . Focusing lens

17. . . Angle adjustment mechanism

Claims (9)

A light source sharing optical system includes: a concave mirror having an opening and a focal plane; a primary mirror facing the concave mirror; and a visible light source disposed between the concave mirror and the secondary mirror a focal plane of the parabolic mirror; a first lens array disposed at the opening of the concave mirror; a second lens array disposed on a focal length of the first lens array; a near-infrared light source disposed at the first Between a lens array and the second lens array, the near-infrared light source has a light emitting surface facing the second lens array; a focuser disposed relative to the first lens array and the second lens array; and a An angle adjustment mechanism is coupled to the concave mirror for controlling a deflection angle of the concave mirror. The light source sharing optical system of claim 1, wherein the visible light source comprises a tungsten filament for emitting a visible light. The light source sharing optical system of claim 1, wherein the visible light source comprises a white light emitting diode for emitting a visible light. A light source sharing optical system according to claim 1, wherein the concave mirror is a parabolic mirror. The light source sharing optical system of claim 1, wherein the concave mirror is an ellipsoid mirror, and the ellipsoid mirror has a first focus and a second focus, and the first focus system Located in the focal plane. The light source sharing optical system of claim 1, wherein the focus is a focusing lens. The light source sharing optical system of claim 1, wherein the focus is a focusing mirror. The light source sharing optical system of claim 1, wherein the secondary mirror is a plane mirror. The light source sharing optical system according to claim 1, wherein the secondary mirror is a curved mirror.