Light source brightness adjusting device and light source brightness adjusting method

Abstract

According to the light source brightness adjusting device and the light source brightness adjusting method provided by the invention, a mechanical switching device in the background technology is not needed, so that the influence of vibration 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 through the light splitting element, the polarization angle of the first polarized light is adjusted by the first polarization rotator to form third polarized light, and the polarization angle of the second polarized light is adjusted by the second polarization rotator to form fourth polarized light. And the light combining element combines 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, so that the brightness of the light output to the objective lens system can be adjusted, and the adjustment of different polarization degrees of the light can be realized to meet the gray scale requirements when different objects are photographed.

Description

Technical Field

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

[0002] In optical measurement, we often encounter situations where the reflectivity of the measured objects varies greatly. Therefore, the brightness of the light source needs to be adjustable 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 method is more common in LED lighting. However, changes in voltage or current generally lead to changes in the lighting spectrum. Changes in the electric power of the light source will also lead to changes in the surrounding temperature, thereby affecting the stability of the light source brightness. This cannot meet the requirements of scenes with high requirements for light source brightness stability.

[0004] The second method is to use a neutral density attenuation sheet to adjust the brightness, but this method requires the cooperation of a mechanical switching device, and the switching speed of the mechanical switching device is relatively slow, and the mechanical switching device will cause vibration, thus affecting the stability of the light source brightness. If a gradient neutral density attenuation sheet is used for brightness adjustment, it will also cause the problem of poor uniformity of the light source brightness. 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 purpose and other related purposes, the present application provides a light source brightness adjustment device, which includes: a light splitting element, 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 for receiving the first polarized light emitted from the beam splitter, and reflecting the first polarized light into the first polarization rotator; the second reflector is used for receiving the second polarized light emitted from the beam splitter, and reflecting the second polarized light into the second polarization rotator;

[0009] The first polarization rotator is used 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 used 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 first preset angle and the second preset angle.

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

[0013] By adopting the light source brightness adjustment device and light source brightness adjustment method of the present application, the mechanical switching device in the background technology is not required, so the stability of the light source brightness affected by vibration can be avoided. The non-polarized light whose brightness is to be adjusted 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 the adjustment of different polarization degrees of the light can be achieved 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 drawings required for use in the embodiments will be briefly introduced below. 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 related drawings can be obtained based on these drawings without paying 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 Description:

[0017] 1 beam splitter; 2 first reflector; 3 first polarization rotator; 4 beam combining element; 5 second polarization rotator; 6 second reflector; 9 relay system. DETAILED DESCRIPTION

[0018] The following describes the implementation methods of the present application through specific specific embodiments, and 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 implementation methods, and the details in the present application can also be modified or changed in various ways 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 without conflict.

[0019] In the embodiments of the present 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 the present application should not be considered as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0020] In the description of the embodiments of the present application, unless otherwise specified, "multiple" means two or more than two. For example, multiple processing units refer to two or more processing units, etc., and multiple elements refer to 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 the polarized light is reflected by the reflector, and then the polarized light is rotated by the polarization rotator, and 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 spectroscopic element 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 spectroscopic element 1, and the first polarized light is P light. The second polarized light is the light reflected from the spectroscopic element 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 spectroscopic element 1 can be a spectroscopic prism (refer to Figure 1 ), beam splitter plate (refer to Figure 2 ) and other splitter elements. In order to improve the decomposition effect of non-polarized light, the splitter element 1 can specifically be a splitter device such as a polarization splitter prism or a polarization splitter 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 (such as a pentagonal prism), and the second reflector 6 is a plane reflector or an optical element equivalent to a plane reflector (such as a pentagonal prism).

[0024] The first polarization rotator 3 is used to receive the first polarized light reflected from the first reflector 2, and rotate the first polarized light by a first preset angle θ1 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 5 is used to receive the second polarized light reflected from the second reflector 6, and rotate the second polarized light by a second preset angle θ2 to form a fourth polarized light, wherein the fourth polarized light has 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 an 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 a P light.

[0027] The first polarization rotator 3 and the second polarization rotator 5 may be liquid crystal polarization rotators (see Figure 1 ), electro-optic polarization rotator (refer to Figure 2), magneto-optical polarization rotator or acousto-optic polarization rotator, etc. Specifically, the liquid crystal polarization rotator uses the characteristics of liquid crystal materials to change the polarization direction of polarized light. The electro-optical polarization rotator changes the refractive index of the electro-optical crystal in 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 voltage is applied, the electro-optical crystal will become a biaxial crystal, thereby generating a birefringence effect, thereby changing the polarization direction of polarized light. The magneto-optical polarization rotator changes the polarization direction of polarized light based on the Faraday magneto-optical effect. The acousto-optic polarization rotator uses the refractive index change caused by the propagation of sound waves in the medium to change the polarization direction of polarized light.

[0028] The light combining element 4 can reflect S light and transmit 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 can transmit the P light component in the third polarized light and reflect the S light component in the third polarized light, and when the light combining element 4 receives the fourth polarized light emitted from the second polarization rotator 5, the light combining element 4 can transmit the P light component in the fourth polarized light and reflect 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 directions perpendicular to each other can be adjusted. The light combining element 4 can be a light combining prism (refer to Figure 1 ), light-combining 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 in the third polarized light and the P light component in the fourth polarized light emitted by the light combining element 4 and outputting them to the objective lens system. The relay system 9 is used to change the size and divergence angle of the aforementioned light beam to match it with the objective lens system. The 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 perform adjustment. Figure 1The following is an example in which the light combining element 4 is 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 preset 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 light component in the third polarized light and the P light component in the fourth polarized light be non-polarized light, the value of the S light component in the third polarized light output to the objective lens system needs to be the same as the value of the P light component in the fourth polarized light. 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 in size. The sizes of 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, so that the light output to the objective lens system by the light source brightness adjustment device is non-polarized light, thereby realizing the adjustment of the illumination brightness of the application scene under non-polarized 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 light, 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 to the objective lens system by the light source brightness adjustment device polarized light, thereby realizing the adjustment of the illumination 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 in a certain ratio, which is used to meet the predetermined grayscale requirements when taking pictures of different objects. For example, an objective lens system using a light source brightness adjustment device to provide illumination light simultaneously shoots 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 the captured objects A and B are close, which is beneficial to the subsequent algorithm processing and improves the adaptability to different application scenarios.

[0036] By adopting the light source brightness adjustment device and light source brightness adjustment method of the present application, the mechanical switching device in the background technology is not required, so the stability of the light source brightness affected by vibration can be avoided. The non-polarized light whose brightness is to be adjusted is decomposed into the first polarized light and the second polarized light by the beam splitter, the polarization angle of the first polarized light is adjusted by the first polarization rotator to form the third polarized light, the polarization angle of the second polarized light is adjusted by the second polarization rotator to form the 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 the light combining element to adjust the brightness of the light output to the objective lens system, and the adjustment of different polarization degrees of the light can be achieved to meet the grayscale requirements when taking pictures of different objects.

[0037] The above is only a preferred implementation of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principles of the present application. These improvements and substitutions 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 for receiving the first polarized light emitted from the beam splitter, and reflecting the first polarized light into the first polarization rotator; the second reflector is used for receiving the second polarized light emitted from the beam splitter, and reflecting the second polarized light into the second polarization rotator; The first polarization rotator is used 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 used 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 beam splitting element includes a beam splitting prism or a beam 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 plate.

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 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 system.

7. A method for adjusting the brightness of a light source, 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 the brightness of a light source according to claim 7, characterized in that: 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 the brightness of a light source according to claim 7, characterized in that: 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 the brightness of a light source according to claim 7, characterized in that: 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 in a certain ratio.

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