Light source brightness adjusting device and light source brightness adjusting method

Abstract

The application provides a light source brightness adjusting device and a light source brightness adjusting method. Without a mechanical switching device in the prior art, vibration influence on the stability of the light source brightness can be avoided. Non-polarized light with brightness to be adjusted is decomposed into first polarized light and second polarized light by a light splitting element. The polarization angle of the first polarized light is adjusted by a first polarization rotator to form third polarized light. The polarization angle of the second polarized light is adjusted by a second polarization rotator to form fourth polarized light. The P light component (or S light component) of the third polarized light and the S light component (or P light component) of the fourth polarized light are combined by a light combining element to realize the adjustment of the brightness of the light output to an objective lens system and the adjustment of different polarization degrees of the light to meet the gray scale requirement when different objects are photographed.

Description

Technical Field

[0001] The present invention relates to the field of optical measurement, and in particular to a light source brightness adjustment device and a light source brightness adjustment method. Background Art

[0002] In optical measurement, it is common to encounter situations where the reflectivity of the measured objects varies greatly. Therefore, it is necessary to adjust the brightness of the light source to ensure that the grayscale of the captured image is not too low or overexposed. Common methods for adjusting the brightness of the light source can be roughly divided into the following two categories:

[0003] The first method is to change the brightness of the light source by adjusting the voltage or current of the light source. This is more common in LED lighting. However, changes in voltage or current generally lead to changes in the lighting spectrum. Secondly, changes in the electric power of the light source will also lead to changes in the surrounding temperature, thereby affecting the brightness stability of the light source. This cannot meet the requirements of scenes with high requirements for light source brightness stability.

[0004] The second method uses neutral density attenuators for brightness adjustment. However, this method requires a mechanical switching device, which is relatively slow and can introduce vibrations that affect the stability of the light source's brightness. Using gradient neutral density attenuators for brightness adjustment can also result in poor brightness uniformity. Summary of the Invention

[0005] One of the purposes of the present application is to provide a light source brightness adjustment device and a light source brightness adjustment method, which can ensure the stability and uniformity of light source brightness adjustment.

[0006] To achieve the above-mentioned and other related objectives, the present application provides a light source brightness adjustment device, which includes: a beam splitter, a reflector, a polarization rotator, and a light combining element; the reflector includes a first reflector and a second reflector; the polarization rotator includes a first polarization rotator and a second polarization rotator;

[0007] The beam splitter is used to split the non-polarized light to be brightness adjusted into a first polarized light and a second polarized light, and output the first polarized light to the first reflector and output the second polarized light to the second reflector, wherein the first polarized light is P light and the second polarized light is S light;

[0008] The first reflector is used to receive the first polarized light emitted from the beam splitter and reflect the first polarized light into the first polarization rotator; the second reflector is used to receive the second polarized light emitted from the beam splitter and reflect the second polarized light into the second polarization rotator;

[0009] The first polarization rotator is configured to receive the first polarized light reflected from the first reflector, and rotate the first polarized light by a first preset angle to form a third polarized light, wherein the third polarized light has a P light component and / or an S light component; the second polarization rotator is configured to receive the second polarized light reflected from the second reflector, and rotate the second polarized light by a second preset angle to form a fourth polarized light, wherein the fourth polarized light has a P light component and / or an S light component;

[0010] The light combining element is used to receive the third polarized light emitted by the first polarization rotator and the fourth polarized light emitted by the second polarization rotator; and output the S light component in the third polarized light and the P light component in the fourth polarized light to the objective system; or output the P light component in the third polarized light and the S light component in the fourth polarized light to the objective system.

[0011] The present application also provides a method for adjusting the brightness of a light source, which uses the above-mentioned light source brightness adjustment device to adjust the brightness of the light source by setting the size of the first preset angle and the second preset angle.

[0012] This application has at least the following beneficial effects:

[0013] The light source brightness adjustment device and light source brightness adjustment method of the present application do not require the mechanical switching device in the background technology, thereby avoiding the impact of vibration on the stability of the light source brightness. The non-polarized light to be adjusted in brightness is decomposed into a first polarized light and a second polarized light by a beam splitter, the polarization angle of the first polarized light is adjusted by a first polarization rotator to form a third polarized light, the polarization angle of the second polarized light is adjusted by a second polarization rotator to form a fourth polarized light, and the P light component (or S light component) of the third polarized light and the S light component (or P light component) of the fourth polarized light are combined by a light combining element to adjust the brightness of the light output to the objective lens system, and can also adjust the different polarization degrees of the light to meet the grayscale requirements when taking pictures of different objects in the same picture, thereby improving the adaptability to different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0015] Figure 1 and Figure 2 Schematic diagram of the optical path structure of a light source brightness adjustment device according to an embodiment of the present application.

[0016] Illustration:

[0017] 1. Beam splitter; 2. First reflector; 3. First polarization rotator; 4. Light combining element; 5. Second polarization rotator; 6. Second reflector; 9. Relay system. DETAILED DESCRIPTION

[0018] The following describes the embodiments of the present application through specific embodiments. Those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. The present application can also be implemented or applied through other different specific embodiments. The details in the present application can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that the following embodiments and features in the embodiments can be combined with each other unless they conflict.

[0019] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be considered to be preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0020] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more, for example, multiple processing units means two or more processing units, etc., multiple elements means two or more elements, etc.

[0021] Reference Figure 1 and Figure 2 This embodiment provides a light source brightness adjustment device, which includes: a beam splitter 1, a reflector, a polarization rotator, and a light combining element 4. The non-polarized light to be adjusted in brightness is sequentially decomposed into polarized light by the beam splitter 1, then reflected by the reflector, and then rotated by the polarization rotator. Finally, the light combining element 4 outputs the light of the required brightness to the objective lens system. The reflector includes a first reflector 2 and a second reflector 6. The polarization rotator includes a first polarization rotator 3 and a second polarization rotator 5. Figure 1 , which is described in detail below.

[0022] The spectrometer 1 is used to decompose the non-polarized light to be adjusted in brightness into a first polarized light and a second polarized light, and transmit the first polarized light to the first reflector 2 and the second polarized light to the second reflector 6. The first polarized light is the light transmitted from the spectrometer 1, and the first polarized light is P light. The second polarized light is the light reflected from the spectrometer 1, and the second polarized light is S light. The polarization directions of P light and S light are perpendicular to each other, that is, the polarization directions of the first polarized light and the second polarized light are perpendicular to each other. The spectrometer 1 can be a spectrometer prism (refer to Figure 1 ), spectroscopic plate (refer to Figure 2 ) and other splitting elements. In order to improve the decomposition effect of non-polarized light, the splitting element 1 can be a splitting device such as a polarization splitting prism or a polarization splitting plate.

[0023] The first reflector 2 is used to receive the first polarized light transmitted from the beam splitter 1 and reflect the first polarized light to the first polarization rotator 3. The second reflector 6 is used to receive the second polarized light reflected from the beam splitter 1 and reflect the second polarized light to the second polarization rotator 5. The first reflector 2 is a plane reflector or an optical element equivalent to a plane reflector (e.g., a pentagonal prism), and the second reflector 6 is a plane reflector or an optical element equivalent to a plane reflector (e.g., a pentagonal prism).

[0024] The first polarization rotator 3 is configured to receive the first polarized light reflected from the first reflector 2 and rotate the first polarized light by a first predetermined angle θ1 to form third polarized light having a P light component and / or an S light component. The second polarization rotator 5 is configured to receive the second polarized light reflected from the second reflector 6 and rotate the second polarized light by a second predetermined angle θ2 to form fourth polarized light having a P light component and / or an S light component.

[0025] For example, when the first preset angle θ1 is 45 degrees, the third polarized light has a P light component and an S light component. When the first preset angle θ1 is 90 degrees, the third polarized light is S light.

[0026] For example, when the second preset angle θ2 is 45 degrees, the fourth polarized light has a P light component and an S light component. When the second preset angle θ2 is 90 degrees, the fourth polarized light is P light.

[0027] The first polarization rotator 3 and the second polarization rotator 5 can be liquid crystal polarization rotators (see Figure 1 ), electro-optic polarization rotator (refer to Figure 2), magneto-optical polarization rotators, or acousto-optic polarization rotators. Specifically, liquid crystal polarization rotators utilize the properties of liquid crystal materials to change the polarization direction of polarized light. Electro-optical polarization rotators change the refractive index of the electro-optical crystal within the electro-optical polarization rotator by applying an electric field. Specifically, when no voltage is applied, the electro-optical crystal (calcite, KDP crystal, etc.) is a uniaxial crystal and does not change the polarization direction of polarized light; when a voltage is applied, the electro-optical crystal becomes a biaxial crystal, generating a birefringence effect that changes the polarization direction of polarized light. Magneto-optical polarization rotators use the Faraday magneto-optical effect to change the polarization direction of polarized light. Acousto-optical polarization rotators use the refractive index changes caused by acoustic waves propagating through a medium to change the polarization direction of polarized light.

[0028] The light combining element 4 is capable of reflecting S light and transmitting P light. Therefore, when the light combining element 4 receives the third polarized light emitted from the first polarization rotator 3, the light combining element 4 is capable of transmitting the P light component in the third polarized light and reflecting the S light component in the third polarized light. When the light combining element 4 receives the fourth polarized light emitted from the second polarization rotator 5, the light combining element 4 is capable of transmitting the P light component in the fourth polarized light and reflecting the S light component in the fourth polarized light. The P light component in the third polarized light is combined with the S light component in the fourth polarized light, and the S light component in the third polarized light is combined with the P light component in the fourth polarized light, so that the amount of light emitted from the light combining element 4 in two mutually perpendicular directions can be adjusted. The light combining element 4 can be a light combining prism (refer to Figure 1 ), combined light flat panel (refer to Figure 2 ) and other light combining elements. In order to improve the light combining effect of non-polarized light, the light combining element 4 can specifically be a light combining element such as a polarization light combining prism or a polarization light combining plate.

[0029] According to the relative position of the objective system and the light combining element 4, the light combining element 4 is used to combine the P light component in the third polarized light and the S light component in the fourth polarized light and output them to the objective system, or to combine the S light component in the third polarized light and the P light component in the fourth polarized light and output them to the objective system.

[0030] The light source brightness adjustment device further includes a relay system 9, which is used to receive the P light component in the third polarized light and the S light component in the fourth polarized light emitted by the light combining element 4 and output them to the objective lens system (refer to Figure 1 ); or for receiving the S light component of the third polarized light and the P light component of the fourth polarized light emitted by the light combining element 4 and outputting them to the objective lens system. Relay system 9 is used to change the size and divergence angle of the aforementioned light beams to match the objective lens system. Relay system 9 may include a relay condenser.

[0031] This embodiment also provides a method for adjusting the brightness of a light source, which uses the above-mentioned light source brightness adjustment device to adjust the brightness. Figure 1The following description will be made by taking the example of the light combining element 4 being used to output the S light component in the third polarized light and the P light component in the fourth polarized light to the objective lens system (not shown) via the relay system 9.

[0032] In some embodiments, if the energy of the third polarized light formed by rotating the first polarized light by the first predetermined angle θ1 is P1, according to Malus's theorem, the energy of the third polarized light that can enter the objective lens system is P11=P1*cos 2 (90°-θ1). If the energy of the fourth polarized light formed by rotating the second polarized light by the second preset angle θ2 is P2, according to Malus's theorem, the energy of the fourth polarized light that can enter the objective lens system is P22=P2*cos 2 (90°-θ2). The energy entering the objective system is the sum of P11 and P12.

[0033] In some embodiments, in order to make the light composed of the S component of the third polarized light and the P component of the fourth polarized light into unpolarized light, the value of the S component of the third polarized light and the value of the P component of the fourth polarized light output to the objective lens system need to be the same. According to the above formula, the value of the third polarized light input to the objective lens system is P11=P1*cos 2 (90°-θ1), the energy in the fourth polarized light is P22=P2*cos 2 (90° - θ2). Since the energy P1 of the third polarized light is equal to the energy P2 of the fourth polarized light, the first preset angle θ1 and the second preset angle θ2 need to be equal. The first preset angle θ1 and the second preset angle θ2 are adjusted so that the P light component and the S light component output to the objective lens system are equal. This ensures that the light output by the light source brightness adjustment device to the objective lens system is unpolarized light, thereby achieving illumination brightness adjustment for application scenarios under unpolarized light.

[0034] In other embodiments, in order to make the light composed of the S light component in the third polarized light and the P light component in the fourth polarized light polarized, referring to the description in the previous paragraph, the first preset angle θ1 and / or the second preset angle θ2 can be adjusted so that the P light component and the S light component output to the objective lens system are different, thereby making the light output by the light source brightness adjustment device to the objective lens system polarized, thereby achieving adjustment of the lighting brightness of the application scene under polarized light.

[0035] By adjusting the size of the first preset angle and / or the second preset angle, the P light component and the S light component output to the objective lens system can be made into a certain ratio, which can be used to meet the predetermined grayscale requirements when photographing different objects. For example, an objective lens system using a light source brightness adjustment device to provide illumination light simultaneously photographs a scene of two objects A and B, wherein the reflectivity of object A to P light is 50% and the reflectivity to S light is 0; the reflectivity of object B to P light is 0 and the reflectivity to S light is 10%. At this time, by setting the size of the first preset angle θ1 and the second preset angle θ2, the ratio of the S light component in the third polarized light to the P light component in the fourth polarized light can be 1:5. At this time, the grayscales of objects A and B captured are close, which is beneficial to the subsequent algorithm processing and improves the adaptability to different application scenarios.

[0036] The light source brightness adjustment device and method of the present application eliminate the need for the mechanical switching device of the background art, thereby preventing vibration from affecting the stability of the light source brightness. The unpolarized light whose brightness is to be adjusted is decomposed into a first polarized light and a second polarized light by a beam splitter. The first polarization rotator adjusts the polarization angle of the first polarized light to form a third polarized light. The second polarization rotator adjusts the polarization angle of the second polarized light to form a fourth polarized light. The light combining element combines the P light component (or S light component) of the third polarized light with the S light component (or P light component) of the fourth polarized light to adjust the brightness of the light output to the objective lens system. Furthermore, the light can be adjusted at different polarization degrees to meet the grayscale requirements when photographing different objects.

[0037] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and replacements can be made without departing from the technical principles of the present application. These improvements and replacements should also be regarded as the scope of protection of the present application.

Claims

1. A light source brightness adjustment device, characterized in that: It includes: a beam splitter, a reflector, a polarization rotator, and a light combining element; the reflector includes a first reflector and a second reflector; the polarization rotator includes a first polarization rotator and a second polarization rotator; The beam splitter is used to split the non-polarized light to be brightness adjusted into a first polarized light and a second polarized light, and output the first polarized light to the first reflector and output the second polarized light to the second reflector, wherein the first polarized light is P light and the second polarized light is S light; The first reflector is used to receive the first polarized light emitted from the beam splitter and reflect the first polarized light into the first polarization rotator; the second reflector is used to receive the second polarized light emitted from the beam splitter and reflect the second polarized light into the second polarization rotator; The first polarization rotator is configured to receive the first polarized light reflected from the first reflector, and rotate the first polarized light by a first preset angle to form a third polarized light, wherein the third polarized light has a P light component and / or an S light component; the second polarization rotator is configured to receive the second polarized light reflected from the second reflector, and rotate the second polarized light by a second preset angle to form a fourth polarized light, wherein the fourth polarized light has a P light component and / or an S light component; The light combining element is used to receive the third polarized light emitted by the first polarization rotator and the fourth polarized light emitted by the second polarization rotator; and output the S light component in the third polarized light and the P light component in the fourth polarized light to the objective system; or output the P light component in the third polarized light and the S light component in the fourth polarized light to the objective system.

2. The light source brightness adjustment device according to claim 1, characterized in that: The light splitting element includes a light splitting prism or a light splitting plate.

3. The light source brightness adjustment device according to claim 1, characterized in that: The light combining element includes a light combining prism or a light combining flat panel.

4. The light source brightness adjustment device according to claim 1, characterized in that: The first reflector is a plane reflector or an optical element equivalent to a plane reflector; the second reflector is a plane reflector or an optical element equivalent to a plane reflector.

5. The light source brightness adjustment device according to claim 1, characterized in that: The first polarization rotator is a liquid crystal polarization rotator, an electro-optical polarization rotator, a magneto-optical polarization rotator, or an acousto-optical polarization rotator; and / or the second polarization rotator is a liquid crystal polarization rotator, an electro-optical polarization rotator, a magneto-optical polarization rotator, or an acousto-optical polarization rotator.

6. The light source brightness adjustment device according to claim 1, characterized in that: The light source brightness adjustment device also includes a relay system, which is used to receive the S light component in the third polarized light and the P light component in the fourth polarized light emitted by the light combining element and output them to the objective lens system; or to receive the P light component in the third polarized light and the S light component in the fourth polarized light and output them to the objective lens system.

7. A method for adjusting light source brightness, characterized in that: The light source brightness adjustment device according to any one of claims 1 to 6 is used to adjust the light source brightness by setting the first preset angle and the second preset angle.

8. The method for adjusting light source brightness according to claim 7, wherein: The first preset angle and the second preset angle are adjusted so that the P light component and the S light component output to the objective lens system are equal.

9. The method for adjusting light source brightness according to claim 7, wherein: The size of the first preset angle and / or the second preset angle is adjusted so that the P light component and the S light component output to the objective lens system are different.

10. The method for adjusting light source brightness according to claim 7, wherein: The first preset angle and / or the second preset angle are adjusted so that the P light component and the S light component output to the objective lens system are in a certain ratio.

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