A small volume scanning system
By optimizing the layout of the LD light-emitting unit, collimating and shaping lens, and F-theta lens, and combining it with an integrated counter lens, the problems of large size and temperature sensitivity of traditional scanning systems have been solved, achieving miniaturization and high-quality imaging.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TIANJIN UNIV
- Filing Date
- 2025-08-13
- Publication Date
- 2026-07-31
AI Technical Summary
Traditional scanning systems suffer from problems such as large size, difficulty in miniaturization, and poor image uniformity due to the susceptibility of multiple lenses to temperature variations.
A specific layout of LD light-emitting unit, collimating and shaping lens and F-theta mirror is adopted, combined with the integrated structure of motor rotating mirror and counter lens, to optimize the beam path to reduce volume and improve stability.
This achievement enables miniaturization of the scanning system and stability of imaging quality, reduces sensitivity to temperature changes, and improves spot uniformity and scanning efficiency.
Smart Images
Figure CN120762203B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of optical scanning technology, and more particularly to a small-volume scanning system. Background Technology
[0002] Traditional optical scanning systems mainly consist of six parts: an LD laser scanning unit, a collimating lens, a shaping lens, a motor, an F-theta lens, and a counter lens. These parts are all distributed in the same plane. Besides converging the light beam on the scanning surface, they also require scanning the scanning spot on the surface at a certain speed. However, it is difficult to miniaturize the scanning optical system that achieves both converging and constant-speed scanning functions. Existing scanners are generally bulky, making it difficult to achieve significant miniaturization and portability. Traditional collimating lenses use aspherical lenses made of plastic to create small and cost-effective beam scanning devices. However, the refractive index of traditional collimating lenses in beam scanning devices changes with temperature, causing variations in image points and poor image uniformity.
[0003] Patent document publication number CN119678088A discloses a scanning optical system including a deflector; and an imaging optical system having a first scanning lens closer to the deflector and a second scanning lens further away from the deflector. However, this patent still has some shortcomings: the use of multiple scanning lenses makes it difficult to further reduce the size, and multiple scanning lenses are more susceptible to temperature effects, resulting in poor image uniformity. Summary of the Invention
[0004] The technical problem to be solved by the present invention is that, in order to solve the problem that multiple scanning lenses make it difficult to further reduce the size and are easily affected by temperature, the present invention provides a small-volume scanning system to solve the above problems.
[0005] The technical solution adopted by this invention to solve its technical problem is as follows: a small-volume scanning system, including an LD light-emitting unit, a collimating and shaping lens, a motor rotating mirror, and an F-theta mirror. The motor rotating mirror and the F-theta mirror are at the same height. The height of the collimating and shaping lens is greater than that of the F-theta mirror. The mirror surface of the collimating and shaping lens is tilted towards the side of the motor rotating mirror. The light beam emitted by the LD light-emitting unit can pass through the collimating and shaping lens and be reflected by the motor rotating mirror into the F-theta mirror. The light beam between the LD light-emitting unit and the motor rotating mirror forms an incident light beam, and the light beam between the motor rotating mirror and the F-theta mirror forms a scanning light beam. The plane where the centers of the LD light-emitting unit, the collimating and shaping lens, and the F-theta mirror are located is the vertical reference plane, and the plane where the centers of the motor rotating mirror and the F-theta mirror are located is the horizontal reference plane. The horizontal reference plane is perpendicular to the vertical reference plane. The incident light beam and the scanning light beam are located in the same vertical plane and are distributed at an acute angle.
[0006] Preferably, the collimating and shaping lens forms a collimating lens surface on the side close to the LD light-emitting unit and a shaping lens surface on the side away from the LD light-emitting unit. The collimating lens surface is a binary surface, and the shaping lens surface is an aspherical surface.
[0007] Preferably, a counter lens is provided on one side edge of the F-theta mirror, and the scanning beam can be reflected into the counter lens by the motor rotating mirror.
[0008] Preferably, the counter lens and the F-theta lens are made of the same lens material and are integrally molded.
[0009] Preferably, the collimating and shaping lens is made of glass or resin.
[0010] Preferably, the distance from the LD light-emitting unit to the center of the motor rotating mirror is greater than the distance from the F-theta mirror to the center of the motor rotating mirror.
[0011] Preferably, the distance from the LD light-emitting unit to the center of the motor rotating mirror is less than or equal to 110 mm.
[0012] The beneficial effects of this invention are as follows: First, by placing the LD light-emitting unit and the collimating and shaping lens obliquely above the motor rotating mirror and the F-theta mirror, the overall planar area and three-dimensional volume occupied by the scanning system are further reduced. Furthermore, the distance from the LD light-emitting unit to the center of the motor rotating mirror does not need to be adaptively shortened. The distance between the two directly determines the design difficulty of the collimating and shaping lens. The greater the distance between the two, the less difficult it is to design the collimating and shaping lens. According to the law of refraction, it is easier to adjust the incident beam into a linear beam by increasing the distance, thereby improving the imaging quality of the scanning beam and the light spot.
[0013] Secondly, the collimating and shaping lens forms a collimating lens surface on the side closest to the LD light-emitting unit. The collimating lens surface is a binary surface, while the shaping lens surface is an aspherical surface. The dispersion characteristics of binary optical devices are independent of the refractive index of the constituent materials and are only related to the wavelength. This characteristic makes the dispersion performance relatively stable when the collimating lens surface is a binary surface, and it is not easily affected by changes in the thermal expansion coefficient of the material. In contrast, the photothermal expansion coefficient of diffractive optical elements is mainly determined by the linear expansion coefficient of the matrix material and is independent of the refractive index characteristics of the material. This further ensures that the collimating lens surface can maintain relatively stable imaging performance when the temperature changes, reducing aberration changes caused by thermal differences. Attached Figure Description
[0014] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.
[0015] Figure 1 This is a schematic diagram of the structure of a counter lens in a small-volume scanning system according to the present invention; Figure 2 This is a schematic diagram showing the positional relationship between the collimating and shaping lens and the F-theta lens in a small-volume scanning system of the present invention.
[0016] Reference numerals in the attached diagram: 1. LD light-emitting unit; 2. Collimating and shaping lens; 3. Motor rotating mirror; 4. F-theta mirror; 5. Incident beam; 6. Scanning beam; 7. Counter lens. Detailed Implementation
[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0018] The concepts involved in this application will first be described with reference to the accompanying drawings. It should be noted that the following descriptions of various concepts are only for the purpose of making the content of this application easier to understand and do not constitute a limitation on the scope of protection of this application; furthermore, the embodiments and features in the embodiments of this application can be combined with each other unless otherwise specified. This application will now be described in detail with reference to the accompanying drawings and embodiments.
[0019] like Figure 1 and Figure 2 As shown, the present invention provides an embodiment of a small-volume scanning system, including an LD light-emitting unit 1, a collimating and shaping lens 2, a motor rotating mirror 3, and an F-theta mirror 4. The motor rotating mirror 3 and the F-theta mirror 4 are at the same height. The height of the collimating and shaping lens 2 is greater than the height of the F-theta mirror 4. The mirror surface of the collimating and shaping lens 2 is tilted towards the side of the motor rotating mirror 3. The light beam emitted by the LD light-emitting unit 1 can pass through the collimating and shaping lens 2 and be reflected by the motor rotating mirror 3 into the F-theta mirror 4. The light beam between the LD light-emitting unit 1 and the motor rotating mirror 3 forms an incident light beam 5, and the light beam between the motor rotating mirror 3 and the F-theta mirror 4 forms a scanning light beam 6.
[0020] One edge of the F-theta mirror 4 extends outward to form a counter lens 7. The scanning beam 6 can be reflected into the counter lens 7 by the motor rotating mirror 3. The counter lens 7 and the F-theta mirror 4 are made of the same lens material and are integrally molded. Integrating the F-theta mirror 4 and the counter lens 7 together effectively reduces the number of lenses and further reduces the overall size of the scanning system.
[0021] The vertical reference plane is the plane where the centers of the LD light-emitting unit 1, the collimating and shaping lens 2, and the F-theta mirror 4 are located. The horizontal reference plane is the plane where the centers of the motor rotating mirror 3 and the F-theta mirror 4 are located. The horizontal reference plane is perpendicular to the vertical reference plane. The incident beam 5 and the scanning beam 6 are located in the same vertical plane and are distributed at an acute angle. That is, the LD light-emitting unit 1 emits the incident beam 5 from the collimating and shaping lens 2 at an angle from the upper side of the motor rotating mirror 3 and is reflected by the motor rotating mirror 3 to form the scanning beam 6 that enters the F-theta mirror 4 in a horizontal direction. By controlling the rotation of the motor rotating mirror 3, the direction of the scanning beam 6 can be adjusted to achieve the scanning action.
[0022] By placing the LD light-emitting unit 1 and the collimating and shaping lens 2 diagonally above the motor rotating mirror 3 and the F-theta mirror 4, compared to the traditional method of placing the LD light-emitting unit 1 next to the motor rotating mirror 3, the overall planar area and three-dimensional volume occupied by the scanning system are further reduced. Furthermore, the distance between the LD light-emitting unit 1 and the center of the motor rotating mirror 3 does not need to be adaptively shortened. The distance between the two directly determines the design difficulty of the collimating and shaping lens 2. The greater the distance between the two, the less difficult it is to design the collimating and shaping lens 2. According to the law of refraction, it is easier to adjust the incident beam 5 into a linear beam by increasing the distance, thereby improving the imaging quality of the scanning beam 6 and the light spot.
[0023] The collimating and shaping lens 2 has a collimating lens surface on the side closest to the LD light-emitting unit 1. The collimating lens surface is a binary surface, while the shaping lens surface is an aspherical surface. The shape of the shaping lens can be cylindrical or a plastic aspherical surface similar to a tire. The dispersion characteristics of binary optical devices are independent of the refractive index of the constituent materials and are only related to the wavelength. This characteristic makes the dispersion performance relatively stable when the collimating lens surface is a binary surface, and it is not easily affected by the change of the thermal expansion coefficient of the material. The photothermal expansion coefficient of diffractive optical elements is mainly determined by the linear expansion coefficient of the matrix material and is independent of the refractive index characteristics of the material. This further ensures that the collimating lens surface can maintain relatively stable imaging performance when the temperature changes, reducing aberration changes caused by thermal differences.
[0024] The distance from the LD light-emitting unit 1 to the center of the motor rotating mirror 3 is less than or equal to 110mm. The distance from the LD light-emitting unit 1 to the center of the motor rotating mirror 3 is greater than the distance from the F-theta mirror 4 to the center of the motor rotating mirror 3. The collimating and shaping lens 2 is made of glass or resin. Using traditional glass lenses can improve the uniformity of the scanning beam 6, but the cost is high. In this embodiment, using resin lenses can effectively reduce the lens manufacturing cost, reduce the overall size of the scanning system, and also reduce the processing difficulty of the collimating and shaping lens 2.
[0025] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. The above are only preferred embodiments of this application. It should be noted that due to the limitations of textual expression, while there are objectively infinite specific structures, those skilled in the art can make several improvements, modifications, or changes without departing from the principles of this application, and can also combine the above technical features in an appropriate manner. These improvements, modifications, changes, or combinations, or the direct application of the inventive concept and technical solution to other situations without modification, should all be considered within the scope of protection of this application.
Claims
1. A small volume scanning system characterized by: The system includes an LD light-emitting unit (1), a collimating lens (2), a motor-driven mirror (3), and an F-theta mirror (4). The motor-driven mirror (3) and the F-theta mirror (4) are at the same height. The height of the collimating lens (2) is greater than the height of the F-theta mirror (4). The mirror surface of the collimating lens (2) is tilted towards the side of the motor-driven mirror (3). The light beam emitted by the LD light-emitting unit (1) can pass through the collimating lens (2) and be reflected by the motor-driven mirror (3) into the F-theta mirror (4). The light beam between the light unit (1) and the motor rotating mirror (3) forms an incident beam (5), and the light beam between the motor rotating mirror (3) and the F-theta mirror (4) forms a scanning beam (6). The plane containing the center of the LD light-emitting unit (1), the collimating and shaping lens (2) and the F-theta mirror (4) is the vertical reference plane, and the plane containing the center of the motor rotating mirror (3) and the F-theta mirror (4) is the horizontal reference plane. The horizontal reference plane is perpendicular to the vertical reference plane. The incident beam (5) and the scanning beam (6) are located in the same vertical plane and are distributed at an acute angle. A counter lens (7) is provided on one side edge of the F-theta mirror (4), and the scanning beam (6) can be reflected into the counter lens (7) through the motor rotating mirror (3). The counter lens (7) and the F-theta lens (4) are made of the same lens material and are integrally formed.
2. The small-volume scanning system as described in claim 1, characterized in that: The collimating and shaping lens (2) forms a collimating lens surface on the side close to the LD light-emitting unit (1), and forms a shaping lens surface on the side away from the LD light-emitting unit (1). The collimating lens surface is a binary surface, and the shaping lens surface is an aspherical surface.
3. A small volume scanning system as claimed in claim 1, characterized in that: The collimating and shaping lens (2) is made of glass or resin.
4. A small volume scanning system as claimed in claim 1, characterized in that: The distance from the LD light-emitting unit (1) to the center of the motor rotating mirror (3) is greater than the distance from the F-theta mirror (4) to the center of the motor rotating mirror (3).
5. A small volume scanning system as claimed in claim 1, characterized in that: The distance from the LD light-emitting unit (1) to the center of the motor rotating mirror (3) is less than or equal to 110 mm.