Polarization projector with high luminous efficiency and depth camera
By introducing a random phase plate and a reflective mirror into the polarization projector, changing the impenetrable light phase and optical path, so that it penetrates the polarization plate again, solving the problem of low light output efficiency of the existing polarization projector and achieving high light output efficiency and the improvement of energy utilization.
Patent Information
- Application Number
- CN202420850767.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-23
- Publication Date
- 2024-12-13
- Estimated Expiration
- 2034-04-23
AI Technical Summary
Existing polarization projectors have problems with large energy loss and low utilization, especially since the polarizer can only penetrate 50% of the polarized light, resulting in low light output efficiency.
By setting a random phase plate and a reflective mirror in the optical path, the impenetrable active light changes the phase and changes the direction of the optical path, so that it is irradiated on the polarizer again, thereby increasing the penetration rate.
After one reflection, it reaches a penetration rate of 75%, and after multiple reflections, it reaches more than 90%, which significantly improves the light output efficiency and energy utilization rate.
Smart Images
Figure CN222167338U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of polarization projection, and in particular to a polarization projector with high light extraction efficiency and a depth camera. Background Art
[0002] A polarization projector is an optical device that is used to generate a beam of light with a specific polarization state. In physics and optics experiments, polarization projectors play an important role because they can help us study the polarization properties of light, which is crucial in many fields such as communications, imaging, and display technology.
[0003] Polarization is a property of light waves that describes the vibration direction of the electric field vector in the light wave. Natural light usually contains all possible vibration directions, while polarized light is light that only vibrates in a specific direction. A polarizer produces polarized light by filtering out unwanted vibration directions and only allowing light with a specific polarization direction to pass through.
[0004] The working principle of the polarization projector is based on the polarization properties of light and the polarization characteristics of certain materials. These materials usually have a special crystal structure that can selectively allow or block light with a specific polarization direction to pass through. When natural light passes through the polarization projector, only light that is consistent with the polarization direction of the projector can pass through, while light in other directions is absorbed or reflected.
[0005] Polarization projectors are widely used in many fields. In the field of communications, the control of polarization state is the key to achieving efficient and stable optical communication. In the field of imaging, polarization cameras use polarization projectors to obtain polarization information of target objects, which helps to improve the contrast and clarity of images. In display technology, polarization projectors are also used in devices such as LCD screens to control the propagation and display effects of light.
[0006] Although there are great differences in the structures of polarization projectors in different fields and the light sources used are also great differences, the polarization projectors in the prior art all have the problems of large energy loss and low utilization rate.
[0007] The disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the utility model. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of the present application. Utility Model Content
[0008] To this end, the utility model arranges a random phase plate and a reflective mirror surface so that the active light that cannot penetrate the polarizer can penetrate the polarizer after the phase is changed, thereby improving the pass rate of the active light and improving the light output efficiency.
[0009] In a first aspect, the utility model provides a polarization projector with high light extraction efficiency, characterized by comprising:
[0010] A light source, for emitting active light;
[0011] A polarizer, located on the light path of the light source;
[0012] A random phase plate, located between the light source and the polarizer;
[0013] A reflective mirror surface is located on the same side of the polarizer as the light source and is used to reflect the active light.
[0014] Optionally, the polarized projector with high light extraction efficiency is characterized in that the reflective mirror surface wraps around a side of the polarizer facing the light source.
[0015] Optionally, the polarized projector with high light extraction efficiency is characterized in that the polarizer completely covers the light path of the light source.
[0016] Optionally, the polarization projector with high light extraction efficiency is characterized in that the random phase plate completely covers the light path of the light source.
[0017] Optionally, the polarization projector with high light extraction efficiency is characterized by further comprising:
[0018] The glass plays a protective role and allows the active light to pass through.
[0019] Optionally, the polarized projector with high light extraction efficiency is characterized in that the polarizer is attached to the glass.
[0020] Optionally, the polarization projector with high light extraction efficiency is characterized in that the glass is connected to the reflective mirror surface to reflect the active light that is not emitted from the glass.
[0021] Optionally, the polarization projector with high light extraction efficiency is characterized in that the distance between the random phase plate and the polarizer is less than 2 mm.
[0022] In a second aspect, the utility model provides a depth camera, characterized in that it includes:
[0023] The polarization projector with high light extraction efficiency as described in any of the above items;
[0024] A receiver is used to receive a reflected signal of the light emitted from the polarization projector with high light extraction efficiency.
[0025] Compared with the prior art, the utility model has the following beneficial effects:
[0026] According to the characteristic that the polarizing plate can only penetrate 50% of the polarized light, the utility model sets a random phase plate to change the phase of the light that cannot penetrate, and uses a reflecting mirror to change the direction of the light path, so that the light after the phase change is irradiated on the polarizing plate again, so that the light penetrating the polarizing plate reaches 75% after one reflection, and reaches more than 90% after multiple reflections, which greatly improves the light extraction efficiency, so that the light projection in the polarized state also has higher light extraction efficiency and energy utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without creative work. By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, purposes and advantages of the utility model will become more obvious:
[0028] Figure 1 It is a structural schematic diagram of a polarization projector with high light extraction efficiency in an embodiment of the utility model;
[0029] Figure 2 A schematic diagram of the optical path of a polarization projector with high light extraction efficiency in an embodiment of the utility model;
[0030] Figure 3 It is a schematic diagram of the structure of a depth camera in an embodiment of the utility model.
[0031] 1- Light source;
[0032] 2- Polarizer;
[0033] 3- Random phase plate;
[0034] 4-Reflective mirror;
[0035] 5- Glass;
[0036] 6-Polarization projector;
[0037] 7-Receiver;
[0038] 11- Active light;
[0039] 12- first transmitted light;
[0040] 13- first reflected light;
[0041] 14- second transmitted light; DETAILED DESCRIPTION
[0042] 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 variations and improvements can be made without departing from the concept of the utility model. These all fall within the scope of protection of the utility model.
[0043] The terms "first", "second", "third", "fourth", etc. (if any) in the specification and claims of the present utility model and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the utility model described here, for example, can be implemented in an order other than those illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.
[0044] The embodiment of the utility model provides a polarization projector with high light extraction efficiency, aiming to solve the problems existing in the prior art.
[0045] The following specific embodiments are used to describe in detail the technical solution of the utility model and how the technical solution of the present application solves the above technical problems. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be repeated in some embodiments. The embodiments of the utility model will be described below in conjunction with the accompanying drawings.
[0046] According to the characteristic that the polarizing plate can only penetrate 50% of the polarized light, the utility model sets a random phase plate to change the phase of the light that cannot penetrate, and uses a reflecting mirror to change the direction of the light path, so that the light after the phase change is irradiated on the polarizing plate again, so that the light penetrating the polarizing plate reaches 75% after one reflection, and reaches more than 90% after multiple reflections, which greatly improves the light extraction efficiency, so that the light projection in the polarized state also has higher light extraction efficiency and energy utilization rate.
[0047] Figure 1 FIG. 1 is a schematic diagram of the structure of a polarization projector with high light extraction efficiency in an embodiment of the utility model. Figure 1 As shown, a polarization projector with high light extraction efficiency in an embodiment of the utility model includes:
[0048] The light source 1 is used for emitting active light.
[0049] Specifically, light source 1 is the core part of the polarization projector, responsible for emitting active light, that is, light without a specific polarization direction. Active light can be light of any wavelength band, such as visible light, infrared light, ultraviolet light, etc. When the active light is infrared light, it can be infrared floodlight or structured light. The light source can be various light sources, including but not limited to LED light sources, incandescent lamps, halogen lamps, fluorescent lamps (fluorescent lamps), energy-saving lamps, lasers, OLEDs (organic light-emitting diodes), plasma light sources and other light sources. Each light source has its advantages and limitations, and the selection of the light source needs to be determined according to the specific application requirements. LED light sources usually have the advantages of high brightness, long life and high energy efficiency.
[0050] The polarizer 2 is located on the light path of the light source.
[0051] Specifically, the polarizer 2 is located in the optical path of the light source 1. Its function is to obtain linearly polarized light from the active light. The polarizer is usually composed of a multilayer film, which contains materials that can absorb or reflect light in a specific polarization direction. The number of polarizers is one. In some embodiments, the polarizer has only one vibration transmission direction, and only light waves vibrating along this direction can pass through. In some embodiments, the polarizer has at least two vibration transmission directions, and the polarization directions of light emitted from different areas of the polarizer are different. The polarization directions of different areas on the polarizer can be vertical or at an angle of 45 degrees, 30 degrees, 15 degrees or any other angle.
[0052] The random phase plate 3 is located between the light source and the polarizer.
[0053] Specifically, a random phase plate (RPP) is an optical element used to introduce random phase changes on the wavefront of a light beam. The surface of a random phase plate has irregular structures that introduce random phase delays on the passing light beam. This phase delay causes the wavefront of the light beam to be distorted, thereby changing the propagation characteristics and focusing performance of the light beam. The design and manufacture of a random phase plate requires precise control of the microstructure of its surface to ensure that the desired phase change can be accurately introduced into the light beam.
[0054] The reflective mirror 4 is located on the same side of the polarizer as the light source and is used to reflect the active light.
[0055] Specifically, the reflective mirror 4 can change the direction of the light so that it propagates along the desired path. The reflective mirror is used to reflect the light beam from the light source so that the light can be reflected and transmitted multiple times inside the polarization projector. Since the reflective mirror usually has a high reflectivity, the energy of the light can be retained to the maximum extent. In the polarization projector, the reflective mirror and the LED light source are located on the same side of the polarizer, which can reflect the active light emitted by the LED light source back to the polarizer and the random phase plate. After multiple reflections and polarization processing, more polarized light beams are finally emitted, thereby improving the light output rate.
[0056] In some embodiments, the reflective mirror wraps the side of the polarizer facing the light source. The reflective mirror wraps the side of the polarizer facing the light source, so that all light on the light source side can only be irradiated on the reflective mirror, the light source and the polarizer, so that the light is reflected to the greatest extent. The reflective mirror is in an arc shape so that the active light is irradiated on the polarizer with the least number of reflections, thereby reducing light loss and improving light output efficiency.
[0057] In some embodiments, the polarizer completely covers the light path of the light source. The size of the polarizer is large enough so that the active light emitted from the light source is directly irradiated on the polarizer without reflection, so that the emitted active light is more uniform. Since the proportion of the emitted light is the highest when it is irradiated on the polarizer for the first time, this embodiment can ensure the uniformity of the active light.
[0058] In some embodiments, the random phase plate completely covers the optical path of the light source. The random phase plate resets the polarization state of all penetrating active light, so as to reset as much light as possible.
[0059] In some embodiments, it also includes: glass 5, which plays a protective role and allows the active light to pass through. The glass can be ordinary glass, tempered glass, etc., which plays a protective role. The glass is transparent to allow the active light to pass through. Depending on the type of active light, different types of glass can be used. For example, if the active light is visible light, the glass can pass the visible light. If the active light is infrared light, the glass can pass the infrared light, and for visible light, it can either pass or not pass. Whether the visible light can pass can be set according to the application scenario.
[0060] In some embodiments, the polarizer is attached to the glass. The polarizer is attached to the glass to minimize light loss and improve light transmission rate.
[0061] In some embodiments, the glass is connected to the reflective mirror surface to reflect the active light that is not emitted from the glass. When the glass is connected to the reflective mirror surface, a closed space is formed inside, thereby maximizing the use of the space and achieving the best reflection effect.
[0062] In some embodiments, the distance between the random phase plate and the polarizer is less than 2 mm. The distance between the random phase plate and the polarizer is less than 2 mm, which can reduce light loss, facilitate installation and fixation, and improve the stability of the polarization projector.
[0063] In some embodiments, the random phase plate is attached to the polarizer. When the random phase plate is attached to the polarizer, light loss is minimized and light emission rate can be increased.
[0064] Figure 2 This is a schematic diagram of the optical path of a polarization projector with high light output efficiency in an embodiment of the utility model. When the light source projects active light 11, the active light intensity is recorded as I. After the active light penetrates the random phase plate 3, it is irradiated on the polarizer 2, and 50%I penetrates the polarizer and is emitted, which is recorded as the first transmitted light 12, and 50%I is reflected by the polarizer, which is recorded as the first reflected light 13. After the first reflected light penetrates the random phase plate, it is irradiated on the reflective mirror 4, and then reflects and penetrates the random phase plate again, and irradiates on the polarizer 2. Since the random phase plate changes the polarization state of the light to a random state, 50%*50%I penetrates the polarizer 2, which is recorded as the second transmitted light 14, and 50%*50%I is reflected again by the polarizer 2, which is recorded as the second reflected light. At this time, the light penetrating the polarizer is 0.75I. When the second reflected light continues to repeat the above path, more light will be emitted from the polarizer, so that the final output light efficiency can reach more than 90%.
[0065] Figure 3 FIG. 1 is a schematic diagram of the structure of a depth camera in an embodiment of the present utility model. Figure 3 As shown, a depth camera in an embodiment of the utility model includes:
[0066] The high light extraction efficiency polarization projector and receiver 7 in the aforementioned embodiment.
[0067] The depth camera is used to measure the depth information of the target object, and belongs to the field of measurement imaging. The type of the receiver 7 matches the polarization projector. The receiver 7 can receive all reflected signals, or a polarizer can be set to receive only polarization states with a specific form.
[0068] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the embodiments can be referred to each other. The above description of the disclosed embodiments enables professionals and technicians in this field to implement or use the utility model. Various modifications to these embodiments will be obvious to professionals and technicians in this field, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the utility model. Therefore, the utility model will not be limited to the embodiments shown herein, but will conform to the widest range consistent with the principles and novel features disclosed herein.
[0069] 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 modifications or variations within the scope of the claims, which does not affect the essence of the present invention.
Claims
1. A polarization projector with high light extraction efficiency, characterized in that: include: A light source, for emitting active light; A polarizer, located on the light path of the light source; A random phase plate, located between the light source and the polarizer; A reflective mirror surface is located on the same side of the polarizer as the light source and is used to reflect the active light.
2. A polarization projector with high light extraction efficiency according to claim 1, characterized in that: The reflective mirror surface wraps a side of the polarizer facing the light source.
3. The polarization projector with high light extraction efficiency according to claim 1, characterized in that: The polarizer completely covers the light path of the light source.
4. The polarization projector with high light extraction efficiency according to claim 1, characterized in that: The random phase plate completely covers the optical path of the light source.
5. The polarization projector with high light extraction efficiency according to claim 1, characterized in that: Also includes: The glass plays a protective role and allows the active light to pass through.
6. The polarization projector with high light extraction efficiency according to claim 5, characterized in that: The polarizing plate is attached to the glass.
7. The polarization projector with high light extraction efficiency according to claim 5, characterized in that: The glass is connected to the reflective mirror surface to reflect the active light that is not emitted from the glass.
8. The polarization projector with high light extraction efficiency according to claim 1, characterized in that: The distance between the random phase plate and the polarizing plate is less than 2 mm.
9. The polarization projector with high light extraction efficiency according to claim 1, characterized in that: The random phase plate is attached to the polarizing plate.
10. A depth camera, characterized in that: include: The polarization projector with high light extraction efficiency as described in any one of claims 1 to 9; A receiver is used to receive a reflected signal of the light emitted from the polarization projector with high light extraction efficiency.