Coaxial regression reflection type photoelectric sensor
By using polarizers and phase offset plates to form polarization films in coaxial regression reflective photoelectric sensors, the problem of lens stress affecting optical signals is solved, the cost is reduced and production efficiency is improved, and the low-cost and efficient photoelectric sensor is realized design.
Patent Information
- Application Number
- CN202420150505.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-01-22
- Publication Date
- 2024-12-10
- Estimated Expiration
- 2034-01-22
AI Technical Summary
In the existing coaxial photoelectric sensor design, the stress distribution of the lens affects the polarization direction of the optical signal, making it cost-effective and difficult to remove, and the machining method increases the cost and installation complexity of the lens.
In coaxial regression reflective photoelectric sensor, a special polarization film is formed by adding a polarizer and a phase offset sheet in front of the lens, which reduces the impact on the lens stress on the optical signal, allows the use of a low-cost lens and phase shifting. The offset plate and polarizer are made into functional films to reduce material and production costs.
It realizes that the lens mold development and production costs are reduced without affecting the optical signal detection performance, and does not need to consider the lens stress distribution, thereby improving the product economy and production efficiency.
Smart Images
Figure CN222145254U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of photoelectric sensors, and in particular to a coaxial regression reflection type photoelectric sensor. Background Art
[0002] The regressive reflective photoelectric sensor usually has a transmitting part and a receiving part. When using the sensor, a reflector is provided opposite the sensor, which is used to return the light emitted by the sensor transmitting part to the receiving part. When there is no object between the light emitted from the light-emitting element and the reflector, the light is returned to the receiving element by the reflector. On the contrary, when there is an object between the light emitted by the light-emitting element and the reflector, the light of the light-emitting element is blocked and the light does not return to the receiving element. The sensor detects whether there is an object based on the strength of the light signal.
[0003] Existing coaxial photoelectric sensor design solutions are as follows Figure 1 As shown, the polarizer is used to convert the light emitted by the light emitting diode into linear polarized light; the analyzer is used to screen the linear polarized light reflected back by the reflector. The polarizer and the analyzer screen the light at a vertical angle of 90 degrees. However, the existing coaxial photoelectric sensor design has the following disadvantages:
[0004] 1. The stress distribution of the lens directly affects the performance of the product, because the stress of the lens will change the polarization direction of the returned linear polarized light, allowing the light signal reflected by other non-reflective plates (such as the light signal reflected by the mirror) to enter the receiving element. When designing the lens mold, the stress distribution of the lens is considered and the stress relief process is used for lens injection molding, but this will increase the mold cost and cannot completely remove the stress inside the lens;
[0005] 2. The existing design scheme adopts machining to process the lens, which has a high cost. In addition, the machining method is not convenient for making buckles, which is inconvenient to install and has a higher cost. Utility Model Content
[0006] In view of the defects in the prior art, the purpose of the utility model is to provide a coaxial regression reflective photoelectric sensor with low mold development cost and low production cost.
[0007] To solve the above problems, the technical solution of the utility model is:
[0008] A coaxial regression-reflective photoelectric sensor comprises a photosensitive diode, a light-emitting diode, a semi-transparent mirror, a lens, a polarizing plate, a phase shifting plate and a reflective plate. The light signal emitted by the light-emitting diode passes through the semi-transparent mirror and then forms parallel light through the lens. The parallel light passes through the polarizing plate to form linearly polarized light. The linearly polarized light then passes through the phase shifting plate to reach the reflective plate. The reflective plate then rotates the light signal and passes through the phase shifting plate and the polarizing plate, and then passes through the lens and the semi-transparent mirror to reach the photosensitive diode.
[0009] Optionally, the semi-transparent and semi-reflective mirror is used to separate the light emitted by the light emitting diode and the light reflected by the reflector, and the lens is used to convert the light of the light emitting diode into parallel light and emit it, while converging the returned light.
[0010] Optionally, the polarizer is used to shape the optical signal into polarized light, and at the same time screen the returning optical signal to remove stray light.
[0011] Optionally, the phase shift plate is used to perform phase shift on the light signal passing through the polarizer, and the phase shift plate rotates the linearly polarized light by 45 degrees to reach the reflector.
[0012] Optionally, the reflector is used to rotate the vibration direction of the polarized light by 90 degrees, and then rotate the vibration direction by another 45 degrees through a phase shift plate before passing through a polarizing plate.
[0013] Optionally, the phase shift plate and the polarizing plate can be made into a functional film by selecting suitable materials.
[0014] Compared with the prior art, the coaxial regressive reflective photoelectric sensor of the utility model adds a polarizing film and a phase shifting film in front of the lens, so that the stress of the lens will not affect the light screening effect of the polarizing film, that is, it will not affect the performance of the product. Therefore, the design scheme of the utility model does not have high requirements on the lens, and a low-cost injection-molded lens with stress can be used, or a machined glass lens can be used, or a high-cost stress-relief lens can be used. In addition, the utility model does not need to consider the stress of the lens, and the lens is injection-molded using a conventional mold, and the mold development cost is relatively low; and suitable materials can be selected to make the phase shifting film and the polarizing film into a functional film, thereby further reducing the material cost and production cost. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Other features, objects and advantages of the present invention will become more apparent by reading the detailed description of non-limiting embodiments with reference to the following drawings:
[0016] Figure 1 It is a structural schematic diagram of a coaxial photoelectric sensor in the prior art;
[0017] Figure 2It is a schematic diagram of the structure of the coaxial regression reflection type photoelectric sensor of the utility model. DETAILED DESCRIPTION
[0018] The utility model is described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the utility model, but do not limit the utility model in any form. It should be pointed out that for those of ordinary skill in the art, several changes and improvements can be made without departing from the concept of the utility model. These all belong to the protection scope of the utility model.
[0019] Specifically, the utility model provides a coaxial regression reflection type photoelectric sensor, such as Figure 2 As shown, the coaxial regression-reflective photoelectric sensor includes a photosensitive diode, a light-emitting diode, a semi-transparent and semi-reflective mirror, a lens, a polarizing plate, a phase shifting plate and a reflective plate.
[0020] Among them, the light-emitting diode is used to convert the pulsed electrical signal into an optical signal. The semi-transparent and semi-reflective mirror is used to separate the light emitted by the light-emitting diode and the light reflected by the reflector. The lens is used to convert the light of the light-emitting diode into parallel light and emit it, while aggregating the returned light. The polarizer is used to shape the optical signal into polarized light, and at the same time filter the returned optical signal to remove stray light. The phase shifter is used to phase shift the optical signal passing through the polarizer, and at the same time rotate the vibration direction of the returned optical signal. The reflector is used to rotate the vibration direction of the polarized light by 90 degrees. The photosensitive diode is used to convert the optical signal into a current / voltage signal.
[0021] The specific working process of the coaxial regression reflection type photoelectric sensor of the utility model is as follows:
[0022] The light signal emitted by the light emitting diode passes through a semi-transparent and semi-reflective mirror, and then forms parallel light A1 through a lens. The parallel light A1 passes through a polarizer to form linearly polarized light A2. The linearly polarized light A2 passes through a phase shift plate to rotate the linearly polarized light 45 degrees to become A3. A3 reaches the reflector, and the reflector rotates A3 90 degrees to become B3. The vibration direction of B3 is rotated 45 degrees again through the phase shift plate to become B2, wherein B2 (equivalent to the vibration direction of the linear polarized light A2 rotated 180 degrees) is consistent with the vibration direction of A2, so B2 can also pass through the polarizer to become B1, and B1 passes through the lens (even if the lens has stress, it will change the vibration direction of B1, but it will not affect the detection performance of the sensor), and then passes through a semi-transparent and semi-reflective mirror to reach the photosensitive diode.
[0023] In an optional embodiment, suitable materials can be selected to make the phase shift plate and the polarizer into a functional film, thereby reducing material costs and production costs.
[0024] In summary, the utility model uses a special polarizing film, and installs the polarizing film in front of the lens. The lens is behind the polarizing film, and the stress of the lens will not affect the light screening effect of the polarizing film, that is, it will not affect the performance of the product. In addition, regardless of the stress of the lens, the lens is injection molded using a conventional mold, and the mold development cost is low.
[0025] The above describes the specific embodiments of the present invention. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. In the absence of conflict, the embodiments of the present application and the features in the embodiments can be combined with each other at will.
Claims
1. A coaxial regressive reflective photoelectric sensor, characterized in that: The coaxial regression-reflective photoelectric sensor includes a photosensitive diode, a light-emitting diode, a semi-transparent mirror, a lens, a polarizer, a phase shift plate and a reflector. The light signal emitted by the light-emitting diode passes through the semi-transparent mirror, and then forms parallel light through the lens. The parallel light passes through the polarizer to form linearly polarized light. The linearly polarized light then passes through the phase shift plate to reach the reflector. The reflector then rotates the light signal and passes through the phase shift plate and the polarizer, and then passes through the lens and the semi-transparent mirror to reach the photosensitive diode.
2. The coaxial regressive reflective photoelectric sensor according to claim 1, characterized in that: The semi-transparent and semi-reflective mirror is used to separate the light emitted by the light emitting diode and the light reflected by the reflector, and the lens is used to convert the light of the light emitting diode into parallel light and emit it, while converging the returned light.
3. The coaxial regressive reflective photoelectric sensor according to claim 1, characterized in that: The polarizer is used to shape the optical signal into polarized light, and at the same time screen the returning optical signal to remove stray light.
4. The coaxial regressive reflective photoelectric sensor according to claim 1, characterized in that: The phase shift plate is used to perform phase shift on the optical signal passing through the polarizer, and the phase shift plate rotates the linear polarized light by 45 degrees to reach the reflector.
5. The coaxial regressive reflective photoelectric sensor according to claim 4, characterized in that: The reflector is used to rotate the vibration direction of the polarized light by 90 degrees, and then rotate the vibration direction by 45 degrees again through the phase shift plate before passing through the polarizer.
6. The coaxial regression reflective photoelectric sensor according to claim 1, characterized in that: By selecting suitable materials, the phase shift plate and polarizing plate can be made into a functional film.