Brake lamp for automobile

Abstract

The invention relates to a brake lamp for an automobile, and belongs to the technical field of brake lamps, the brake lamp comprises a control module, a light source, a spreadlight lens and a semi-light-guide strip, the spreadlight lens and the semi-light-guide strip are sequentially arranged in the light path direction of the light source, and the spreadlight lens is used for diverging light emitted from the light source; a polarizing plate is arranged between the spreadlight lens and the semi-light-guide strip, the polarizing plate is electrically connected with a control module, the control module adjusts the divergence degree of light emitted from the spreadlight lens by instructing the polarizing plate to rotate, and the control module is used for judging whether the vehicle speed exceeds a threshold value or not. The control module reduces the divergence degree of the spreadlight lens to the light emitted by the light source when the vehicle speed exceeds a threshold value, and improves the divergence degree of the spreadlight lens to the light emitted by the light source when the vehicle speed is lower than the threshold value.

Description

Technical Field

[0001] The invention belongs to the technical field of brake lights, and in particular relates to a brake light for an automobile. Background Art

[0002] When a car brakes, it needs to send a signal to the rear so that vehicles or pedestrians behind can see that the car in front is slowing down. Therefore, the car brake light is a tool used to send a light signal to the rear when the car brakes.

[0003] The lens body in a general high-mounted brake light is basically a double-layer structure, and the light transmission is prone to discontinuity, which affects the user experience. For this reason, Chinese patent application CN109724050A discloses a new three-layer Fresnel lens optical unit high-mounted brake light, including a lens body; the lens body includes a first layer lens, a second layer lens, and a third layer lens; the first layer lens is provided with a plurality of convex portions on the side facing the second layer lens, and there are intervals between the convex portions, and the other side of the first layer lens is provided with a patterned portion formed by a plurality of trapezoidal connection combinations; the second layer lens is provided with a plurality of serrations on the side facing the first layer lens, and the second layer lens is provided with a wavy pattern on the third layer lens; the third layer lens is flat on the side facing the second layer lens, and is a convex surface protruding outward on the side facing the outside of the lens body. It has a simple structure, compact fit, easy use, reasonable design, and beautiful appearance; it is technical and economical;

[0004] However, different light signals need to be transmitted in different situations. For example, when a vehicle is traveling at a higher speed, there is a greater probability that the vehicle is traveling on an open road, and the speed of surrounding vehicles is also high, so the braking distance is longer. When braking, it is necessary to give braking reminders to vehicles as far away as possible, reminding the following vehicles to brake as far away as possible. At this time, there is no need to scatter the light. Instead, the light needs to be concentrated and emitted backwards to remind the rear vehicles at a long distance. In normal times, the brake light needs to be scattered all around to improve the uniformity of the light. For this reason, a car brake light with an adjustable light scattering degree and good braking reminder effect is needed. Summary of the invention

[0005] In order to solve the above problems existing in the prior art, the present invention provides a brake light for an automobile, which has the characteristics of adjustable scattering degree and good brake prompting effect.

[0006] The purpose of the present invention can be achieved through the following technical solutions:

[0007] A brake light for an automobile, comprising a control module, a light source, a polarizing lens and a semi-light-guiding strip, wherein the polarizing lens and the semi-light-guiding strip are sequentially arranged along the light path direction of the light source, and the polarizing lens is used to diverge the light emitted from the light source;

[0008] The semi-light-guiding strip comprises a sawtooth surface and a light-homogenizing surface sequentially arranged along the light path, wherein the sawtooth surface is used to make the light emitted from the polarizing lens parallel, and the light-homogenizing surface is used to homogenize the light emitted from the sawtooth surface in horizontal and vertical directions;

[0009] A polarizing plate is arranged between the polarizing lens and the semi-light-guiding strip, and the polarizing plate is electrically connected to the control module. The control module adjusts the divergence degree of the light emitted from the polarizing lens by instructing the polarizing plate to rotate. The control module is used to determine whether the vehicle speed exceeds a threshold value. When the vehicle speed exceeds the threshold value, the control module reduces the divergence degree of the polarizing lens to the light emitted from the light source, and when the vehicle speed is lower than the threshold value, the control module increases the divergence degree of the polarizing lens to the light emitted from the light source.

[0010] As a preferred technical solution of the present invention, the polarizing lens includes a concave lens, a primary polarizing hole and a secondary polarizing hole arranged along the light path, the concave lens is used to diverge the light incident on the polarizing lens, the primary polarizing hole is used to diverge the light emitted from the concave lens, and the secondary polarizing hole is used to further diverge the light emitted from the primary polarizing hole. There are two polarizing plates, which are respectively arranged on both sides of the light exiting surface of the polarizing lens to adjust the divergence degree of the light emitted from the polarizing lens.

[0011] As a preferred technical solution of the present invention, the control module is pre-input with a standard vehicle speed V0, the polarizing plate is pre-input with a standard tilt angle, and the rotation direction of the polarizing plate to make the reflected light close to the center of the first polarizing hole is taken as a reference direction. The control module instructs the angle of the polarizing plate to tilt A° toward the reference direction with the standard tilt angle as the origin, wherein A=V / V0×c, and c is a pre-input constant.

[0012] As a preferred technical solution of the present invention, the control module is also electrically connected to a visibility sensor, and the control module obtains visibility through the visibility sensor and determines whether the reflectivity exceeds a threshold value. When the judgment result is yes, the control module corrects downward the divergence degree of the polarized lens to the light emitted by the light source, and when the judgment result is no, the control module corrects upward the divergence degree of the polarized lens to the light emitted by the light source.

[0013] As a preferred technical solution of the present invention, the control module obtains visibility F through a visibility sensor, and the control module instructs the angle of the polarizing plate to tilt A×A1° toward a reference direction with a standard tilt angle as the origin, where A1=F0 / F×d, and F0 and d are pre-input constants.

[0014] As a preferred technical solution of the present invention, a control panel is provided, wherein the control panel is electrically connected to the control module, and the control panel is used to display the tilt angle of the polarizing plate relative to the standard tilt angle.

[0015] As a preferred technical solution of the present invention, a light collecting plate is arranged between the polarizing lens and the light source, and the light collecting plate is used to collect the light emitted by the light source and make the concentrated light enter the polarizing lens.

[0016] As a preferred technical solution of the present invention, a surface of the light collecting plate close to the polarizing lens is etched with a pattern.

[0017] The beneficial effects of the present invention are:

[0018] (1) By setting a polarizing lens and a semi-light-guiding strip to diverge and evenly distribute the light from a single LED light source, a relatively uniform illumination effect can be obtained without setting up multiple LED light sources to form an array, and a light signal can be emitted in the direction required by the designer, thereby completing the basic functions of the brake light while reducing power consumption and structural complexity;

[0019] (2) By making the control module reduce the divergence degree of the polarized lens to the light emitted by the light source when the vehicle speed exceeds the threshold, and increase the divergence degree of the polarized lens to the light emitted by the light source when the vehicle speed is below the threshold, it is completed that when the vehicle is traveling at a higher speed, it is necessary to concentrate the light and emit it backward. When reminding the rear vehicle at a long distance, the light is concentrated to increase the light propagation distance, thereby increasing the reminder distance. When the vehicle speed is low, it is necessary to expand the scattering range to remind more people, and the light propagation range is increased;

[0020] (3) By causing the control module to correct downward the divergence of the polarized lens on the light emitted by the light source when it is determined that the visibility is too low, and to correct upward the divergence of the polarized lens on the light emitted by the light source when it is above a threshold, the light can be further concentrated and the light penetration can be improved when the weather conditions are poor and the visibility is low, thereby increasing the light propagation distance. When the visibility is good and there is no need to sacrifice the lighting range to increase the propagation distance, the light propagation range can be increased. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to facilitate understanding by those skilled in the art, the present invention is further described below with reference to the accompanying drawings.

[0022] Figure 1 It is a structural schematic diagram of the present invention;

[0023] Figure 2 It is a schematic structural diagram of the polarized lens of the present invention;

[0024] Figure 3 Schematic diagram of the optical path of the polarizing lens of the present invention;

[0025] Figure 4 A schematic diagram of the optical path of the present invention after the polarizing plate is rotated away from the reference direction;

[0026] Description of main component symbols:

[0027] In the figure: 1, polarizing lens; 11, concave lens; 12, first polarizing hole; 13, second polarizing hole; 14, polarizing plate; 2, semi-light-guiding strip; 21, serrated surface; 22, light-homogenizing surface; 23, light-collecting plate. DETAILED DESCRIPTION

[0028] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation methods, structures, features and effects of the present invention are described in detail below in conjunction with the accompanying drawings and preferred embodiments.

[0029] See also Figure 1-4 , a brake light for an automobile, comprising a control module, a light source, a polarizing lens and a semi-light-guiding strip, wherein the polarizing lens and the semi-light-guiding strip are sequentially arranged along the light path direction of the light source, and the polarizing lens is used to diverge the light emitted from the light source;

[0030] Specifically, the light source is an LED light-emitting chip, the light source is electrically connected to the control module, the control module instructs the start and stop of the light source, and the light-emitting surface of the light source is arranged directly opposite to the light-entering surface of the polarizing lens, so that the light emitted by the light source can enter the light-entering surface of the polarizing lens;

[0031] The semi-light-guiding strip is a rectangular plate-shaped structure as a whole. One bottom surface of the rectangular plate-shaped semi-light-guiding strip is arranged toward the light-emitting surface of the polarizing lens, and the other bottom surface is the light-emitting surface of the brake light.

[0032] After the light enters the polarizing lens, it is diverged by the polarizing lens and diffuses outward. Then, the scattered light reaches all parts of the light incident surface of the semi-light-guiding strip.

[0033] Since it is necessary to ensure that the light is emitted evenly from the entire light-emitting surface of the brake light, after the light is diverged by the polarizing lens, if it is not converged to be parallel, most of the light will continue to propagate in a straight line and cannot propagate to the light-emitting surface of the semi-light-guiding strip, but will irradiate the surrounding structure of the fixed brake light and be absorbed by the surrounding structure, resulting in poor lighting effect. Therefore, the semi-light-guiding strip first converges the light into parallel light, so that the light reaching each part of the light-entering surface of the semi-light-guiding strip becomes perpendicular to the light-entering surface. At the same time, since the semi-light-guiding strip is a plate-like structure, the light perpendicular to the light-entering surface can be emitted in a direction perpendicular to the light-emitting surface, completing the convergence of the scattered light by the semi-light-guiding strip.

[0034] After being folded, the light distribution in some spaces of the semi-light-guiding strip is denser, and the light distribution in some spaces is sparser. At this time, the lighting uniformity is still poor, and the light needs to be evened. A wave pattern layer and a convex layer are arranged in the semi-light-guiding strip along the light propagation direction. The wave pattern layer is used to evenly distribute the light horizontally, and the convex layer is used to evenly distribute the light vertically.

[0035] For the polarized lens, specifically, the cross-section of the polarized lens is trapezoidal as a whole, the short flat side of the trapezoidal polarized lens is the light incident surface, which is arranged toward the light source, the long flat side is the light exiting surface, which is arranged toward the semi-light-guiding strip, and the surface shape of the light exiting surface is arranged to be corrugated, and at the same time, a concave lens is arranged on the side of the polarized lens close to the light incident surface, the plane incident surface of the concave lens coincides with the light incident surface of the polarized lens, forming the light incident surface of the polarized lens, and the light exiting concave surface faces the light exiting surface, and the polarized lens is sequentially arranged with a primary polarized hole and a secondary polarized hole along the propagation direction of the light, the light incident surface of the primary polarized hole is arranged toward the light exiting concave surface of the concave lens, the light exiting surface is arranged toward the light incident surface of the secondary polarized hole, and the light exiting surface of the secondary polarized hole is arranged toward the light exiting surface of the polarized lens, and the arrangement positions of the primary polarized hole and the secondary polarized hole ensure that the light is scattered by the concave lens and then incident on the light incident surface of the primary polarized hole, and the light is emitted from the primary polarized hole and then incident on the light incident surface of the secondary polarized hole;

[0036] The primary polarizing hole includes polarizing plane 1 and polarizing plane 2 arranged along the light path. The light enters the secondary polarizing hole after being deflected by polarizing plane 1 and polarizing plane 2. The function of polarizing plane 1 is to deflect the light, and the function of polarizing plane 2 is to diffuse the light.

[0037] At the same time, there are a total of several secondary polarizing holes, which are distributed between the primary polarizing hole and the light exit surface of the polarizing lens. Each secondary polarizing hole is also provided with a polarizing plane 1 and a polarizing plane 2. The secondary polarizing holes close to the edge of the polarizing lens are used to scatter part of the light to the sides of the polarizing lens, and part of the light to the center of the polarizing lens. The secondary polarizer located at the center of the polarizing lens is used to scatter the light to the two sides. At this time, several light rays can be more evenly distributed on the two sides and the center of the light exit surface of the polarizing lens, completing the scattering of the polarizing lens;

[0038] Compared with the solution of directly setting up multiple LED light sources, by setting up polarized lenses and semi-light-guiding strips to diverge and evenly distribute the light of a single LED light source, a relatively uniform illumination effect can be obtained without setting up multiple LED light sources to form an array, and light signals can be emitted in the direction required by the designer, completing the basic functions of the brake light while reducing power consumption and structural complexity;

[0039] When the brake lights in the above scheme are actually used, different light signals need to be transmitted in different situations. For example, when a vehicle is traveling at a high speed, there is a high probability that the vehicle is traveling on an open road section, and the speed of surrounding vehicles is also high, and the braking distance is long. When braking, it is necessary to give a braking reminder to vehicles as far away as possible, reminding the following vehicles to brake as far away as possible. At this time, there is no need to scatter the light, but the light needs to be concentrated and emitted backward to remind the rear vehicles at a long distance. In normal times, the brake light needs to be scattered all around to improve the uniformity of the light. For this reason, it is necessary to adjust the degree of light scattering. For this reason, a polarizing plate is provided between the polarizing lens and the semi-light-guiding strip, and the polarizing plate is electrically connected to the control module. The control module adjusts the divergence of the light emitted from the polarizing lens by instructing the polarizing plate to rotate. The control module is used to determine whether the vehicle speed exceeds the threshold. When the vehicle speed exceeds the threshold, the control module reduces the divergence of the light emitted from the light source by the polarizing lens, and when the vehicle speed is lower than the threshold, the control module increases the divergence of the light emitted from the light source by the polarizing lens.

[0040] Specifically, since the polarizing lens is in the shape of a quadrangular prism with a trapezoidal cross section, and the two parallel surfaces are respectively the light incident surface and the light exiting surface, the light scattering direction is to diffuse outward along the extension direction of the two inclined surfaces of the polarizing lens. Therefore, when it is necessary to gather the light, a line perpendicular to the center point of the light exiting surface of the polarizing lens is used as a reference line, and the light along the extension direction of the two inclined surfaces needs to be gathered toward the reference line, that is, a reflector is arranged on the extension plane of the two inclined surfaces, and the angle of the reflector relative to the light exiting surface of the polarizing lens is adjustable. For this purpose, each polarizing plate includes an electric rotating shaft, and the axis center lines of the two rotating shafts are perpendicular to the reference line. The axis center line of each polarizing plate rotating shaft is respectively located on a plane extending from an inclined surface to the direction of the semi-light guide strip. The polarizing plate is arranged on the extension plane of the two inclined surfaces of the polarizing lens. At this time, the light diffused along the extension plane of the two inclined surfaces contacts the polarizing plate;

[0041] In this embodiment, the polarizing plate is a reflector and the light diffused on the extended plane along the two inclined surfaces is reflected and propagates toward the reference line after contacting the polarizing plate;

[0042] When it is necessary to reduce the degree of scattering and concentrate the light in the direction of the reference line, it is necessary to increase the angle between the light and the polarizing plate so that the light can deviate from the original diffusion direction along the extension plane of the two inclined surfaces and turn to the reference line. At this time, it is necessary to move the polarizing plate closer to a state perpendicular to the light exiting surface of the polarizing lens. At this time, the control module instructs the polarizing plate to turn closer to a state perpendicular to the light exiting surface of the polarizing lens.

[0043] When the scattering degree needs to be increased so that the light moves in the direction of diffusion on the extension plane of the two inclined surfaces, it is necessary to reduce the angle between the light and the polarizing plate and reduce the degree to which the light deviates from the original propagation direction. At this time, it is necessary to move the polarizing plate away from the state perpendicular to the light emitting surface of the polarizing lens. At this time, the control module instructs the polarizing plate to turn away from the state perpendicular to the light emitting surface of the polarizing lens.

[0044] Specifically, the control module is pre-input with a standard vehicle speed V0, the polarizing plate is pre-input with a standard tilt angle, the polarizing plate rotates in a direction that makes the reflected light close to the center of the first polarizing hole as a reference direction, and the control module instructs the angle of the polarizing plate to tilt A° toward the reference direction with the standard tilt angle as the origin, wherein A=V / V0×c, and c is a pre-input constant;

[0045] When the vehicle speed V is relatively large, the scattering degree needs to be reduced. At this time, the value of A=V / V0×c is relatively large. When the control module instructs the angle of the polarizer to tilt A° toward the reference direction with the standard tilt angle as the origin, the polarizer is instructed to turn to a state close to the state perpendicular to the light-emitting surface of the polarizing lens when the scattering degree needs to be reduced.

[0046] When the vehicle speed V is small, the scattering degree needs to be maintained or increased. At this time, the value of A=V / V0×c is small. When the control module instructs the angle of the polarizer to tilt A° toward the reference direction with the standard tilt angle as the origin, the polarizer is instructed to turn away from the state perpendicular to the light-emitting surface of the polarizing lens when the scattering degree needs to be maintained or increased.

[0047] By enabling the control module to reduce the divergence of the polarized lens to the light emitted by the light source when the vehicle speed exceeds the threshold, and to increase the divergence of the polarized lens to the light emitted by the light source when the vehicle speed is below the threshold, it is achieved that when the vehicle is traveling at a higher speed, it is necessary to concentrate the light and emit it backwards, and when reminding the rear vehicle at a long distance, the light is concentrated to increase the light propagation distance, thereby increasing the warning distance; when the vehicle speed is low and the scattering range needs to be expanded to remind more people, the light propagation range is increased.

[0048] Since the coverage of a single light source is still limited after being diverged, parallelized and evenly distributed, in actual use, several brake lights can be optionally provided, and the several brake lights can be arranged along the design direction to form a brake light array to achieve the lighting effect required by the designer.

[0049] In some cases, weather may also affect the light propagation distance and the warning distance of the brake lights. When the weather is bad, foggy and visibility is low, it is necessary to further concentrate the light to improve the light penetration and thus improve the light propagation distance. When the weather is good and visibility is high, there is no need to sacrifice the lighting range to improve the propagation distance. For this reason, the control module is also electrically connected to a visibility sensor. The control module obtains visibility through the visibility sensor and determines whether the reflectivity exceeds a threshold. When the judgment result is yes, the control module corrects downward the divergence degree of the polarized lens to the light emitted by the light source. When the judgment result is no, the control module corrects upward the divergence degree of the polarized lens to the light emitted by the light source.

[0050] Specifically, the visibility sensor is used to detect the propagation distance of the wavelength of the brake light in the current environment in real time, obtain the visibility F, and upload it to the control module once per second. After receiving the data each time, the control module instructs the angle of the polarizer to tilt A×A1° toward the reference direction with the standard tilt angle as the origin, where A1=F0 / F×d, and F0 and d are pre-entered constants;

[0051] When the visibility F is low, it means that the light needs to be further concentrated, and the angle of the polarizer tilted toward the reference direction with the standard tilt angle as the origin needs to be increased. At this time, the value of A1=F0 / F×d is large, and the value of A×A1° is large. When the control module instructs the angle of the polarizer to tilt toward the reference direction with the standard tilt angle as the origin by A×A1°, when the light needs to be further concentrated, the angle of the polarizer tilted toward the reference direction with the standard tilt angle as the origin is increased;

[0052] When the visibility F is high, it means that there is no need to further concentrate the light, and there is no need to increase the angle of the polarizer tilted toward the reference direction with the standard tilt angle as the origin. At this time, the value of A1=F0 / F×d is small, and the value of A×A1° is small. When the control module instructs the angle of the polarizer to tilt toward the reference direction with the standard tilt angle as the origin by A×A1°, it is completed to reduce the angle of the polarizer tilted toward the reference direction with the standard tilt angle as the origin when there is no need to further concentrate the light;

[0053] By causing the control module to correct downward the degree of divergence of the polarized lens to the light emitted by the light source when it is judged that the visibility is too low, and to correct upward the degree of divergence of the polarized lens to the light emitted by the light source when it is above a threshold, it is possible to further concentrate the light and improve the light penetration when the weather conditions are poor and the visibility is low, thereby increasing the light propagation distance; and when the visibility is good and there is no need to sacrifice the lighting range to increase the propagation distance, the light propagation range is improved.

[0054] In order to remind passengers or drivers of the current brake light status, a control panel is also included. The control panel is electrically connected to the control module and is used to display the inclination angle of the polarizing plate relative to the standard inclination angle.

[0055] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A brake light for an automobile, characterized in that: It includes a control module, a light source, a polarizing lens and a semi-light-guiding strip, wherein the polarizing lens and the semi-light-guiding strip are sequentially arranged along the light path direction of the light source, and the polarizing lens is used to diverge the light emitted from the light source; The semi-light-guiding strip comprises a sawtooth surface and a light-homogenizing surface sequentially arranged along the light path, wherein the sawtooth surface is used to make the light emitted from the polarizing lens parallel, and the light-homogenizing surface is used to homogenize the light emitted from the sawtooth surface in horizontal and vertical directions; A polarizing plate is arranged between the polarizing lens and the semi-light-guiding strip, and the polarizing plate is electrically connected to the control module. The control module adjusts the divergence degree of the light emitted from the polarizing lens by instructing the polarizing plate to rotate. The control module is used to determine whether the vehicle speed exceeds a threshold value. When the vehicle speed exceeds the threshold value, the control module reduces the divergence degree of the polarizing lens to the light emitted from the light source, and when the vehicle speed is lower than the threshold value, the control module increases the divergence degree of the polarizing lens to the light emitted from the light source.

2. The automobile brake light according to claim 1, characterized in that: The polarizing lens comprises a concave lens, a primary polarizing hole and a secondary polarizing hole arranged along the light path. The concave lens is used to diverge the light incident on the polarizing lens, the primary polarizing hole is used to diverge the light emitted from the concave lens, and the secondary polarizing hole is used to further diverge the light emitted from the primary polarizing hole. There are two polarizing plates in total, which are respectively arranged on both sides of the light emitting surface of the polarizing lens to adjust the divergence degree of the light emitted from the polarizing lens.

3. The automobile brake light according to claim 1, characterized in that: The control module is pre-input with a standard vehicle speed V0, and the polarizing plate is pre-input with a standard tilt angle. The rotation direction of the polarizing plate that makes the reflected light close to the center of the first polarizing hole is taken as a reference direction. The control module instructs the angle of the polarizing plate to tilt A° toward the reference direction with the standard tilt angle as the origin, where A=V / V0×c, and c is a pre-input constant.

4. The automobile brake light according to claim 1, characterized in that: The control module is also electrically connected to a visibility sensor. The control module obtains visibility through the visibility sensor and determines whether the reflectivity exceeds a threshold value. When the judgment result is yes, the control module corrects downward the divergence degree of the polarized lens to the light emitted by the light source. When the judgment result is no, the control module corrects upward the divergence degree of the polarized lens to the light emitted by the light source.

5. The automobile brake light according to claim 4, characterized in that: The control module obtains visibility F through a visibility sensor, and instructs the angle of the polarizing plate to tilt A×A1° toward a reference direction with a standard tilt angle as the origin, wherein A1=F0 / F×d, and F0 and d are pre-input constants.

6. The automobile brake light according to claim 1, characterized in that: It comprises a control panel, which is electrically connected to the control module and is used to display the inclination angle of the polarizing plate relative to the standard inclination angle.

7. The automobile brake light according to claim 1, characterized in that: A light collecting plate is arranged between the polarizing lens and the light source, and the light collecting plate is used to collect the light emitted by the light source and allow the concentrated light to enter the polarizing lens.

8. The automobile brake light according to claim 7, characterized in that: A pattern is etched on the surface of the light collecting plate at one side close to the polarizing lens.

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