An optical system for reducing the off-axis blind zone of a laser rangefinder sensor

Abstract

This utility model relates to the field of optical system technology, and in particular to an optical system for reducing the blind zone of an off-axis laser rangefinder. The system includes a transmitting optical path and a receiving optical path, both of which are off-axis. The transmitting optical path includes a laser emitting tube and a transmitting lens fixedly disposed in front of the laser emitting tube. The receiving optical path includes a receiving lens, a frosted plate, and a photosensitive receiver. The photosensitive receiver is fixedly disposed behind the receiving lens, and the frosted plate is fixedly disposed between the receiving lens and the photosensitive receiver. The system provided by this utility model has a simple process, low manufacturing cost, can reduce the blind zone of the laser rangefinder, and effectively solves the problem of weak backlight signal when the laser rangefinder is used for close-range ranging.

Description

Technical Field

[0001] This utility model relates to the field of optical system technology, and in particular to an optical system for reducing the off-axis optical path blind zone of a laser rangefinder. Background Technology

[0002] The core working principle of a laser rangefinder is as follows: the laser rangefinder emits a laser beam towards the target, and the target reflects back a portion of the laser signal, known as the echo beam, which is captured by the optical receiving system within the laser rangefinder. Off-axis optical paths refer to laser beams that are physically separate, with their optical axes parallel or forming a small angle. Coaxial optical paths refer to laser beams that share the same optical axis. While coaxial laser rangefinders have a smaller blind zone, due to design limitations, their effective receiving area is smaller than that of off-axis optical paths for the same external dimensions. Furthermore, the receiving lenses in coaxial optical paths are typically designed with irregular shapes, increasing manufacturing costs and complicating assembly processes.

[0003] Currently, the solution to reduce the off-axis optical path blind zone of laser rangefinders is to improve the receiving lens structure, such as changing the receiving lens to an irregular shape. In this irregular shape, part of the receiving lens's area is used to receive near-range signal light, improving the blind zone, while the other part is used to receive long-range signal light. However, this not only increases manufacturing costs, but also introduces stray light due to the irregular shape, thus affecting signal quality. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide an optical system that reduces the blind zone of the off-axis optical path of a laser rangefinder. The system is simple to manufacture and has low production cost. It can reduce the blind zone of the laser rangefinder and effectively solve the problem of weak backlight signal when the laser rangefinder is measuring at close range.

[0005] This utility model is achieved through the following solution: An optical system for reducing the off-axis blind zone of a laser ranging sensor includes an emitting optical path and a receiving optical path, both of which are off-axis optical paths. The emitting optical path includes a laser emitting tube and an emitting lens fixedly disposed in front of the laser emitting tube. The receiving optical path includes a receiving lens, a frosted plate, and a photosensitive receiver. The photosensitive receiver is fixedly disposed behind the receiving lens, and the frosted plate is fixedly disposed between the receiving lens and the photosensitive receiver.

[0006] The optimized frosted pads are made of plastic or glass materials.

[0007] The optimized frosted pad has a haze of 50% to 90%.

[0008] The optimized frosted sheet has a transmittance of 90%.

[0009] Furthermore, the frosted sheet and the photosensitive receiving surface of the photosensitive receiver are set at an angle.

[0010] The optimized angle between the frosted sheet and the photosensitive receiving surface of the photosensitive receiver is between 2° and 30°.

[0011] Furthermore, the receiving optical path is also provided with an optical filter, which is fixedly disposed between the photosensitive receiver and the frosted plate, and the optical filter and the photosensitive receiving surface of the photosensitive receiver are arranged parallel to each other.

[0012] The optimized optical filter has a bandwidth of 50 nanometers.

[0013] Beneficial effects of the utility model: The optical system for reducing the off-axis optical path blind zone of a laser rangefinder provided by this utility model has the following advantages: 1. Compared with the technology of improving the receiving lens structure in coaxial optical paths, the method of reducing the blind zone of laser rangefinders by setting a frosted plate has low manufacturing cost and simple process.

[0014] 2. The tilted setting of the frosted plate can further prevent stray light reflected from the frosted plate from entering the receiving lens, thus ensuring the signal quality of the laser rangefinder.

[0015] 3. By placing an optical filter between the photosensitive receiver and the frosted plate, the problem of weak reflected light signal during close-range ranging is solved. In addition, the optical filter is small in size and low in cost, reducing the risk of optical filter breakage. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of this utility model.

[0017] In the diagram: 1. Laser emitter; 2. Emitting lens; 3. Receiving lens; 4. Frosted glass; 5. Optical filter; 6. Photosensitive receiver. Detailed Implementation

[0018] An optical system for reducing the off-axis optical path blind zone of a laser rangefinder is shown in the schematic diagram below. Figure 1 As shown, it includes an emitting optical path and a receiving optical path. The emitting optical path and the receiving optical path are off-axis optical paths. The emitting optical path includes a laser emitting tube 1 and an emitting lens 2 fixedly disposed in front of the laser emitting tube. The receiving optical path includes a receiving lens 3, a frosted plate 4 and a photosensitive receiver 6. The photosensitive receiver is fixedly disposed behind the receiving lens, and the frosted plate is fixedly disposed between the receiving lens and the photosensitive receiver.

[0019] This invention provides an optical system for reducing the off-axis optical path blind zone of a laser rangefinder. A laser emitter emits laser light towards the target, a emitting lens collimates the diverging light emitted by the laser emitter into parallel light, and a receiving lens converges the light reflected from the target for reception by a photosensitive receiver. When the laser rangefinder is used for close-range ranging, such as when the distance between the target and the sensor housing is 0 to 100 cm, the angle of the light incident on the receiving lens is outside the receiving lens's field of view. The photosensitive receiver cannot receive the reflected light beam, resulting in a blind zone. By placing a frosted plate between the receiving lens and the photosensitive receiver, the light entering the photosensitive receiver is dispersed, allowing a portion of the light signal to enter the photosensitive receiver smoothly, thereby effectively reducing the blind zone of the laser rangefinder.

[0020] The optimized frosting disc is made of plastic or glass. The frosting disc is a thin sheet made of plastic or glass, and the manufacturing process is simple and the cost is relatively low.

[0021] The optimized frosted sheet has a haze of 50% to 90%, which allows the light entering the photosensitive receiver to achieve a good diffusion effect.

[0022] The optimized frosted glass has a transmittance of 90%, ensuring that light passing through it does not lose energy.

[0023] Furthermore, the angled arrangement between the frosted sheet and the photosensitive receiving surface of the photosensitive receiver can prevent reflected light from the surface of the frosted sheet from entering the receiving lens and forming stray light, which would affect the accuracy of blind zone ranging.

[0024] The optimized angle between the frosted sheet and the photosensitive receiving surface of the photosensitive receiver is between 2° and 30°, further preventing reflected light from the frosted sheet surface from incident on the receiving lens and forming stray light, which would affect the accuracy of blind zone ranging.

[0025] Furthermore, the receiving optical path is also provided with an optical filter 5, which is fixedly disposed between the photosensitive receiver and the frosted plate, and the optical filter and the photosensitive receiving surface of the photosensitive receiver are arranged parallel to each other.

[0026] Generally, an optical filter can only achieve a good filtering effect when light is incident at a 0° angle. The light returning from the observed target converges after passing through the receiving lens. Therefore, in existing technologies, the optical filter is usually placed in front of the receiving lens. However, this setup requires a large optical filter, resulting in high costs, and the large size of the optical filter also poses a risk of breakage. This invention places the optical filter behind a frosted glass, which has the following advantages: First, after the light beam passes through the frosted glass, part of the beam is incident at 0° to the optical filter, cleverly solving the problem of weak return signals during close-range ranging due to poor filtering effects; second, the size of the optical filter can be made very small, reducing costs by tens to hundreds of times and lowering the risk of breakage.

[0027] The optimized optical filter has a bandwidth of 50 nanometers, which allows the laser rangefinder's own beam to pass through while resisting interference from external light sources such as sunlight, thus ensuring ranging accuracy.

[0028] In summary, the optical system proposed in this invention for reducing the blind zone of the off-axis optical path of a laser rangefinder is simple in process and low in manufacturing cost. It can reduce the blind zone of the laser rangefinder and effectively solve the problem of weak backlight signal when the laser rangefinder is measuring at close range, thereby ensuring the ranging accuracy of the laser rangefinder.

[0029] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. An optical system for reducing the off-axis optical path blind zone of a laser rangefinder, characterized in that: It includes an emitting optical path and a receiving optical path, which are off-axis optical paths. The emitting optical path includes a laser emitting tube and an emitting lens fixed in front of the laser emitting tube. The receiving optical path includes a receiving lens, a frosted plate, and a photosensitive receiver. The photosensitive receiver is fixed behind the receiving lens, and the frosted plate is fixed between the receiving lens and the photosensitive receiver.

2. The optical system for reducing the off-axis optical path blind zone of a laser rangefinder sensor according to claim 1, characterized in that: The abrasive pad is made of plastic or glass.

3. The optical system for reducing the off-axis optical path blind zone of a laser rangefinder sensor according to claim 1, characterized in that: The haze of the frosted pad is between 50% and 90%.

4. The optical system for reducing the off-axis optical path blind zone of a laser rangefinder according to claim 1, characterized in that: The frosted glass has a transmittance of 90%.

5. An optical system for reducing the off-axis optical path blind zone of a laser rangefinder sensor according to claim 1, characterized in that: The frosted sheet and the photosensitive receiving surface of the photosensitive receiver are set at an angle.

6. The optical system for reducing the off-axis optical path blind zone of a laser rangefinder according to claim 5, characterized in that: The angle between the frosted sheet and the photosensitive receiving surface of the photosensitive receiver is between 2° and 30°.

7. The optical system for reducing the off-axis optical path blind zone of a laser rangefinder according to claim 1, characterized in that: The receiving optical path is also provided with an optical filter, which is fixedly disposed between the photosensitive receiver and the frosted plate, and the optical filter and the photosensitive receiving surface of the photosensitive receiver are arranged parallel to each other.

8. An optical system for reducing the off-axis optical path blind zone of a laser rangefinder according to claim 7, characterized in that: The optical filter has a bandwidth of 50 nanometers.

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