CN218916533U - Luminance meter capable of automatically correcting distance error - Google Patents
Luminance meter capable of automatically correcting distance error Download PDFInfo
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- CN218916533U CN218916533U CN202223576296.0U CN202223576296U CN218916533U CN 218916533 U CN218916533 U CN 218916533U CN 202223576296 U CN202223576296 U CN 202223576296U CN 218916533 U CN218916533 U CN 218916533U
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Abstract
The utility model provides a luminance meter capable of automatically correcting distance errors, which comprises a lens, a photoelectric detector and an electronic measurement control unit, wherein the lens, a focusing unit linked with the lens, an inclined baffle, a photoelectric receiving and transmitting pair and an aperture diaphragm are arranged on the lens; the aperture diaphragm is arranged between the lens and the photoelectric detector, and the light to be detected enters from the lens and then is received by the photoelectric detector through the aperture diaphragm; the photoelectric receiving and transmitting pair is electrically connected with the electronic measurement control unit and comprises a light emitter and a light receiver which are oppositely arranged; the focusing device also comprises a matching piece which synchronously converts the rotary motion of the focusing unit into linear motion, and the inclined baffle is arranged on the matching piece and is positioned between the light emitter and the light receiver; when the focusing unit moves, the inclined baffle sheet and the photoelectric receiving and transmitting pair relatively move to change the light receiving quantity of the light receiver, and the electronic measurement control unit corrects the response of the photoelectric detector according to the electric signal converted by the light receiving quantity, so that the response error caused by the change of the distance is effectively reduced.
Description
Technical Field
The utility model relates to the field of optical radiation measurement, in particular to a brightness meter capable of automatically correcting distance errors.
Background
Imaging brightmeters are well known devices that use an optical system to image a surface to be measured onto the plane of a detector and measure brightness by a non-contact method. According to the measuring working principle, the following relation between the illuminance of the detector surface of the imaging brightness meter and the brightness of the corresponding surface to be measured can be derived by utilizing geometrical optics and photometry knowledge:
wherein E is the illuminance of the imaging brightness meter corresponding to the detector surface, L is the brightness of the surface to be measured,
is the effective light-passing area of the lens, τ is the transmittance (transmissivity) of the optical system, and>
is the focal length of the lens>
Is the distance of the lens from the surface to be measured (called the measurement distance). The brightness is measured by using a brightness meter based on the brightness of the surface to be measured and the illuminance of the corresponding area of the detector, but the response value and the distance are +.>
Even if the standard brightness is constant, the light energy received by the detector surface changes once the distance changes, the brightness of the surface to be detected and the illuminance of the detector surface do not have a strict proportional relationship, and the brightness measurement generates errors.
At present, a fixed diaphragm which does not move along with an imaging lens is usually adopted in the existing luminance meter and is fixed in an optical system, so that the light transmission solid angle transmitted to an imaging surface at different distances is guaranteed to be a constant value, and the technical scheme can eliminate distance errors to a certain extent. However, since the change of the measured distance may also cause the transmittance and reflectance of light on the lens to change, the imaging quality to change, and other error factors related to the measured distance, the above method cannot better solve the problem that the brightness measurement still has a distance error.
Disclosure of Invention
Aiming at the defects of the prior art, the utility model provides a brightness meter capable of automatically correcting distance errors, which aims to correct brightness response, improve focusing precision of the brightness meter and reduce response errors caused by distance changes.
In order to solve the technical problems, the utility model provides a luminance meter capable of automatically correcting distance errors, which comprises a lens, a photoelectric detector and an electronic measurement control unit, wherein the lens, a focusing unit linked with the lens, an oblique baffle plate, a photoelectric receiving and transmitting pair and an aperture diaphragm are arranged on the lens; the aperture diaphragm is arranged between the lens and the photoelectric detector, and the aperture diaphragm and the photoelectric detector are relatively static; the light to be measured is received by a photoelectric detector through an aperture diaphragm after entering from a lens, a color filter or a color filter color wheel for correcting the spectral response of the photoelectric detector is arranged in front of the photoelectric detector, and the photoelectric detector is electrically connected with an electronic measurement control unit; the photoelectric receiving and transmitting pair is electrically connected with the electronic measurement control unit and comprises a light emitter and a light receiver which are oppositely arranged, wherein the light emitter emits light rays to the light receiver, and a light field is formed between the light emitter and the light receiver. The oblique baffle is arranged on the focusing unit and is positioned between the light emitter and the light receiver, and the focusing unit drives the oblique baffle and the photoelectric receiving-transmitting pair to move relatively when in motion, wherein a light field between the light emitter and the light receiver is positioned on a relative movement path of the oblique baffle; when the oblique baffle moves in the light field, the oblique baffle changes the light receiving quantity of the light receiver, the photoelectric receiving and transmitting pair converts the light receiving quantity into corresponding electric signals and transmits the corresponding electric signals to the electronic measurement control unit, and the electronic measurement control unit calculates an image distance according to the electric signals and corrects the response of the photoelectric detector according to the size of the image distance. Wherein the lens is one lens or a lens group consisting of a plurality of lenses. Providing a color filter in front of the photodetector to enable the photodetector to be poweredSpectral response of detector and human eye luminous efficiency functionV(λ) And matching, or arranging a color filter color wheel in front of the photoelectric detector, wherein the color filters on the color wheel respectively match the response of the color filters to the incident light beam with a color tristimulus value function, so as to realize the measurement of the brightness (and chromaticity) of the light beam passing through the aperture diaphragm.
The focusing of the brightness meter in the technical scheme can be realized by manually rotating the focusing unit or automatically driving the focusing unit to rotate by a motor.
As a technical scheme, the focusing unit is of a rotary structure, the focusing unit further comprises a matching piece which converts rotary motion of the focusing unit into linear motion synchronously, and the inclined baffle is arranged on the matching piece and located between the light emitter and the light receiver. The rotation angle of the focusing unit corresponds to the front-back displacement of the matching piece, and the lens linked with the focusing unit moves to a clear focusing position by rotating the focusing unit.
As a technical scheme, the device also comprises a motor, wherein the motor is connected with the focusing unit and is electrically connected with the electronic measurement control unit; the motor drives the focusing unit to move under the control of the electronic measurement control unit. The automatic focusing of the lens and the automatic correction of the distance error can be realized by driving the focusing unit to move through the motor, so that the error caused by manual operation is avoided, and the measurement efficiency is improved. The motor and the focusing unit are connected in a mode including but not limited to gear connection, magnetic connection, buckle connection and the like.
It will be understood that when an element is referred to herein as being "disposed" or "disposed" on another element, it can be directly on the other element or one or more intervening elements may be present therebetween. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or one or more intervening elements may be present therebetween.
Specifically, the focusing unit rotates to drive an optical structure (i.e. a lens) inside the lens to move back and forth, when the focusing unit moves, the inclined baffle plate and the photoelectric receiving and transmitting pair move relatively, and as the relative moving path of the inclined baffle plate is positioned on the light field between the light emitter and the light receiver, the light receiving quantity of the light receiver changes along with the movement of the inclined baffle plate, the photoelectric receiving and transmitting pair converts the light receiving quantity into a corresponding electric signal to be transmitted to the electronic measurement control unit, and the electronic measurement control unit can convert the movement parameters of the lens according to the change rule of the received electric signal, calculate the image distance, calculate the distance correction coefficient according to the size of the image distance, automatically correct the response of the photoelectric detector, and further effectively reduce the measurement error caused by the change of the distance. The distance correction coefficient can be obtained through calculation or pre-calibration. The luminance meter measures the same uniform luminance source at a series of different distances from the measurable closest distance to infinity, and the response at each distance should be the same in the absence of a distance error. By using this principle, the relationship between the response error of the photodetector and the distance can be obtained. And comparing the response value of the brightness meter under the calibration distance with the magnitude of the same uniform light source measured under different distances to obtain a series of distance correction coefficients under the distance, and obtaining the continuous distance correction coefficients by an interpolation method. The response value after the measurement distance is changed is corrected by the distance correction coefficient, so that the measurement error caused by the change of the measurement distance can be avoided or reduced, and the measurement precision of the luminance meter under different measurement distances can be improved.
As a technical scheme, the oblique baffle plate can be of an opaque sheet structure, and the cross section of the oblique baffle plate in the thickness direction is triangular. Because the cross section shape of the oblique baffle is triangle-shaped, when the oblique baffle moves to different positions in the light field of the photoelectric receiving and transmitting pair, the light field area shielded by the oblique baffle is different, so that the receiving amount of the light receiver is different, and further, the photoelectric receiving and transmitting pair can generate different electric signals according to different light receiving amounts, namely, different electric signals correspond to different positions of the oblique baffle. Based on the above, according to the electric signal generated when the oblique baffle plate moves in the optical field of the photoelectric receiving and transmitting pair, the motion parameter of the lens can be converted, the image distance is calculated, and the distance correction coefficient is calculated according to the size of the image distance, so that the response of the photoelectric detector is automatically corrected.
As a technical scheme, the outer surface of the focusing unit is provided with a plurality of stripes, so that manual focusing is more convenient and labor-saving.
As a technical scheme, the device also comprises a storage device electrically connected with the electronic measurement control unit and used for storing the focus information and/or calibration information of the lens, so that the measurement is simpler and more convenient, and the measurement efficiency is further improved.
As a technical scheme, the photoelectric detector is a single-channel photoelectric detector or a two-dimensional array multichannel photoelectric detector, and is positioned at the image plane position of the lens to realize the measurement of the spectral radiance and chromaticity of the measured object.
As a technical scheme, the size of the light transmission hole of the aperture diaphragm is continuously adjustable so as to adapt to response analysis of different brightness sources.
As a technical scheme, the electronic measurement control unit further comprises an image definition identification unit. When focusing, a user can identify the image of a measured object through the image definition identification unit, if the imaging is unclear, the focusing unit is rotated again until the imaging is clear, meanwhile, the photoelectric receiving and transmitting pair converts a received optical signal into an electric signal and transmits the electric signal to the electronic measurement control unit, and the electronic measurement control unit corrects the response of the photoelectric detector according to the electric signal converted by the light receiving amount, so that a more accurate brightness value is obtained.
The utility model has the beneficial effects that: the utility model provides a brightness meter capable of automatically correcting distance errors, which is characterized in that an oblique baffle sheet is used for triggering photoelectric receiving and transmitting pairs to generate electric signal changes to determine the motion state of a lens, an electronic measurement control unit is used for calculating an image distance, and the response of a photoelectric detector is corrected according to the size of the image distance.
Drawings
FIG. 1 is a schematic diagram of an automatic distance error correction luminance meter according to an embodiment of the present utility model;
FIG. 2 is a cross-sectional view of an auto-correcting distance error luminance meter according to a first embodiment;
fig. 3 and fig. 4 are schematic diagrams of the positional relationship between the oblique baffle and the photoelectric transceiver pair in the first embodiment;
FIG. 5 is a schematic diagram showing the change of the shielding area of the inclined baffle plate when the inclined baffle plate moves between the photoelectric receiving and transmitting pairs in the embodiment;
FIG. 6 is a schematic diagram of a voltage signal generated by the photoelectric transceiver pair when the inclined baffle of the first embodiment moves;
FIG. 7 is a schematic diagram of an automatic distance error correction luminance meter according to a second embodiment;
FIG. 8 is a cross-sectional view of an auto-correcting distance error luminance meter according to a second embodiment;
in the figure: the device comprises a 1-lens, a 2-aperture diaphragm, a 3-photoelectric detector, a 4-electronic measurement control unit, a 5-focusing unit, a 6-light emitter, a 7-light receiver, an 8-inclined baffle and a 9-motor.
Detailed Description
The following detailed description of the utility model is given by way of illustration only and not by way of limitation, as will be understood by those skilled in the art in conjunction with the accompanying drawings. It will be appreciated by those skilled in the art that modifications may be made to the following embodiments without departing from the scope of the utility model. The scope of the utility model is defined by the appended claims.
Example 1
The embodiment provides a luminance meter capable of automatically correcting distance errors, see fig. 1 and 2, wherein fig. 1 is a schematic structural diagram, and fig. 2 is a cross-sectional diagram, and the luminance meter comprises a lens, a photoelectric detector (3) and an electronic measurement control unit (4), wherein the lens is provided with a lens (1), a focusing unit (5) linked with the lens (1), an oblique baffle (8), a photoelectric receiving and transmitting pair and an aperture diaphragm (2); the aperture diaphragm (2) is arranged between the lens (1) and the photoelectric detector (3), wherein the aperture diaphragm (2) and the photoelectric detector (3) are relatively static; the light to be measured enters from the lens (1) and then passes through the aperture diaphragm (2) to be received by the photoelectric detector (3), a color filter or a color filter color wheel for correcting the spectral response of the photoelectric detector is arranged in front of the photoelectric detector (3), and the photoelectric detector (3) is electrically connected with the electronic measurement control unit (4); the photoelectric transceiver pair is electrically connected with the electronic measurement control unit (4) and comprises a light emitter (6) and a light receiver (7) which are oppositely arranged; the oblique baffle (8) is arranged on the focusing unit (5) and is positioned between the light emitter (6) and the light receiver (7), the schematic diagrams of the position relationship between the oblique baffle and the photoelectric receiving and transmitting pair are shown in fig. 3 and fig. 4 respectively, wherein fig. 3 is a front view, and fig. 4 is a top view. When the focusing unit (5) moves, the inclined baffle (8) and the photoelectric receiving and transmitting pair are driven to move relatively, so that the light receiving amount of the light receiver (7) is changed, a change schematic diagram of the shielding area of the inclined baffle when the inclined baffle moves between the photoelectric receiving and transmitting pairs is shown in fig. 5, and a schematic diagram of a voltage signal generated by the photoelectric receiving and transmitting pair when the inclined baffle moves in one direction is shown in fig. 6. The electronic measurement control unit (4) corrects the response of the photodetector (3) based on the electric signal converted from the light reception amount. Wherein the size of the light transmission hole of the aperture diaphragm (2) is continuously adjustable. The photoelectric detector (3) is a two-dimensional array type multichannel photoelectric detector and is positioned at the image plane position of the lens (1). The inclined baffle (8) is of a light-tight sheet structure, and the cross section of the inclined baffle in the thickness direction is triangular.
In the above embodiment, since the cross-sectional shape of the oblique baffle is triangular (as shown in fig. 4), when the oblique baffle moves in the optical field of the photoelectric transceiver pair, the area of the optical field blocked by the oblique baffle (the area of the hatched portion in the figure) is different (as shown in fig. 5), so that the light receiving amount of the light receiver is different, and the photoelectric transceiver pair generates different voltage signals according to the different light receiving amounts, that is, the different voltage signals correspond to different positions of the oblique baffle (as shown in fig. 6). According to different voltage signals generated by the photoelectric receiving and transmitting pair when the inclined baffle sheet and the photoelectric receiving and transmitting pair relatively move, the motion parameters of the lens can be converted, the image distance is calculated, and the distance correction coefficient is calculated according to the image distance, so that the response of the photoelectric detector is automatically corrected.
In the above embodiment, preferably, the electronic measurement control unit (4) further includes an image sharpness recognition unit. When focusing, a user can identify the image of a measured object through the image definition identification unit, if the imaging is unclear, the focusing unit is regulated again to make the imaging clear, meanwhile, the photoelectric receiving and transmitting pair converts a received optical signal into an electric signal and transmits the electric signal to the electronic measurement control unit, and the electronic measurement control unit corrects the response of the photoelectric detector according to the electric signal converted by the light receiving amount, so that a more accurate brightness value is obtained.
Example two
The embodiment provides a luminance meter capable of automatically correcting distance errors, see fig. 7 and 8, wherein fig. 7 is a schematic structural diagram, and fig. 8 is a cross-sectional diagram, and the luminance meter comprises a lens, a photoelectric detector (3), a motor (9) and an electronic measurement control unit (4), wherein the lens (1), a rotary focusing unit (5) linked with the lens (1), an oblique baffle (8), a photoelectric receiving and transmitting pair and an aperture diaphragm (2) are arranged on the lens; the aperture diaphragm (2) is arranged between the lens (1) and the photoelectric detector (3), and the aperture diaphragm (2) and the photoelectric detector (3) are relatively static; the light to be measured enters from the lens (1) and then passes through the aperture diaphragm (2) to be received by the photoelectric detector (3), a color filter or a color filter color wheel for correcting the spectral response of the photoelectric detector is arranged in front of the photoelectric detector (3), and the photoelectric detector (3) and the motor (9) are respectively and electrically connected with the electronic measurement control unit (4); the motor (9) is connected with the focusing unit (5) through a gear, and the motor (9) drives the focusing unit (5) to move under the control of the electronic measurement control unit (4). The photoelectric transceiver pair is electrically connected with the electronic measurement control unit (4) and comprises a light emitter (6) and a light receiver (7) which are oppositely arranged; the focusing unit (5) further comprises a matching piece which converts the rotary motion of the focusing unit into linear motion synchronously, and the inclined baffle (8) is arranged on the matching piece and is positioned between the light emitter (6) and the light receiver (7). When the motor (9) drives the focusing unit (5) to move, the inclined baffle (8) and the photoelectric receiving and transmitting pair are driven to move relatively, so that the light receiving amount of the light receiver (7) is changed. The electronic measurement control unit (4) corrects the response of the photodetector (3) based on the electric signal converted from the light reception amount. The size of the light passing hole of the aperture diaphragm (2) is continuously adjustable, and the photoelectric detector (3) is a single-channel photoelectric detector.
In the above embodiment, the oblique baffle (8) is in an opaque sheet structure, and the cross section of the oblique baffle in the thickness direction may be trapezoidal, so that when the oblique baffle moves in the optical field of the photoelectric receiving and transmitting pair, the area of the optical field blocked by the oblique baffle is different, so that the receiving amount of the optical receiver is different, and the photoelectric receiving and transmitting pair generates different electric signals according to different light receiving amounts, that is, the different electric signals correspond to different positions of the oblique baffle. According to different electric signals generated by the photoelectric receiving and transmitting pair when the oblique baffle sheet and the photoelectric receiving and transmitting pair relatively move, the motion parameters of the lens can be converted to obtain, then the image distance is calculated, and the distance correction coefficient is calculated according to the size of the image distance, so that the response of the photoelectric detector is automatically corrected.
According to the embodiment, the motor (9) drives the focusing unit (5) to move, so that automatic focusing of the lens and automatic correction of distance errors can be realized, errors caused by manual operation are avoided, and the measurement efficiency is improved.
Claims (7)
1. The brightness meter capable of automatically correcting the distance error is characterized by comprising a lens, a photoelectric detector (3) and an electronic measurement control unit (4), wherein the lens is provided with a lens (1), a focusing unit (5) linked with the lens (1), an inclined baffle (8), a photoelectric receiving and transmitting pair and an aperture diaphragm (2); the aperture diaphragm (2) is arranged between the lens (1) and the photoelectric detector (3), and the aperture diaphragm (2) and the photoelectric detector (3) are relatively static; the light to be measured enters from the lens (1) and then passes through the aperture diaphragm (2) to be received by the photoelectric detector (3), a color filter or a color filter color wheel for correcting the spectral response of the photoelectric detector (3) is arranged in front of the photoelectric detector (3), and the photoelectric detector (3) is electrically connected with the electronic measurement control unit (4); the photoelectric transceiver pair is electrically connected with the electronic measurement control unit (4) and comprises a light emitter (6) and a light receiver (7) which are oppositely arranged; the oblique baffle (8) is arranged on the focusing unit (5) and is positioned between the light emitter (6) and the light receiver (7), and the oblique baffle (8) and the photoelectric receiving and transmitting pair are driven to move relatively when the focusing unit (5) moves, so that the light receiving amount of the light receiver (7) is changed; the electronic measurement control unit (4) corrects the response of the photodetector (3) based on the electric signal converted from the light reception amount.
2. A luminance meter for automatically correcting distance errors according to claim 1, characterized in that it further comprises a motor (9), said motor (9) being connected to the focusing unit (5) and to the electronic measurement control unit (4); the motor (9) drives the focusing unit (5) to move under the control of the electronic measurement control unit (4).
3. The luminance meter for automatically correcting a distance error according to claim 1, wherein the inclined baffle (8) is of a light-tight sheet-like structure having a triangular cross-sectional shape in the thickness direction.
4. The luminance meter for automatically correcting distance errors according to claim 1, wherein the photodetector (3) is a single-channel detector or a two-dimensional array type multichannel photodetector, and the photodetector (3) is located at the image plane position of the lens (1).
5. A luminance meter for automatically correcting distance errors according to claim 1, characterized in that the size of the light passing aperture of the aperture stop (2) is continuously adjustable.
6. A luminance meter for automatically correcting distance errors according to claim 1, characterized in that the electronic measurement control unit (4) further comprises an image sharpness recognition unit.
7. The automatic distance error correction luminance meter according to claim 1, wherein the focusing unit (5) has a rotary structure, the focusing unit (5) further comprises a matching member for synchronously converting the rotary motion into linear motion, and the oblique baffle (8) is disposed on the matching member and is located between the light emitter (6) and the light receiver (7).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223576296.0U CN218916533U (en) | 2022-12-30 | 2022-12-30 | Luminance meter capable of automatically correcting distance error |
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| Application Number | Priority Date | Filing Date | Title |
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| CN202223576296.0U CN218916533U (en) | 2022-12-30 | 2022-12-30 | Luminance meter capable of automatically correcting distance error |
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| CN218916533U true CN218916533U (en) | 2023-04-25 |
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| CN202223576296.0U Active CN218916533U (en) | 2022-12-30 | 2022-12-30 | Luminance meter capable of automatically correcting distance error |
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