Contrast test stand

Abstract

The utility model relates to a contrast test support, this contrast test support sets up between the back side of projector and screen, it includes support frame and testing arrangement. Testing arrangement includes mounting plate, solid overturn motor, polaroid, lux meter and lux meter integrating sphere light detection head. Overturn motor is connected with polaroid, is used for driving polaroid to overturn up and down. Polaroid and mounting plate between fixedly be provided with lux meter integrating sphere light detection head, the below of lux meter integrating sphere light detection head is provided with lux meter. Polaroid, lux meter and lux meter integrating sphere light detection head all set up with two groups. The mounting plate is slidably arranged on the support frame, which facilitates adjusting the height of the testing device to test the lighting conditions of different light paths in the vertical direction of the screen. When all the to-be-tested light paths of the screen are tested, the display result of the lux meter can be viewed, and then the test conditions or parameters can be optimized or adjusted according to the test result, which is simple and efficient in operation and high in measurement accuracy.

Description

Technical Field

[0001] This utility model relates to the field of optical testing equipment, and in particular to a contrast testing bracket. Background Technology

[0002] Screen brightness refers to the brightness of the reflected light generated when light from a projector is reflected onto the screen. Excessive brightness can be glaring, while insufficient brightness can cause eye strain. Therefore, brightness is a crucial indicator of film projection quality. Consequently, improving and maintaining screen brightness to meet specifications has become a common concern for cinemas. To ensure high-quality color images projected onto the large screen, screen brightness must be measured to analyze the operational status of the cinema's projection equipment, enabling targeted maintenance and repairs. Currently, most testing methods involve an inspector sitting in front of the screen and visually assessing the illuminance at various points, which is both inaccurate and inefficient.

[0003] Therefore, a contrast testing bracket is needed to solve the above problems. Utility Model Content

[0004] This utility model relates to a contrast ratio testing bracket. This bracket uses a set of testing devices positioned between the projector and the back of the screen to detect the screen's illuminance, improving testing accuracy and efficiency. The testing device can be moved as a whole using a movable support frame, making it convenient and easy to operate. The polarizer in the testing device can be turned on or off, allowing testing of the illuminance of natural light and polarized light at each point on the screen. By adjusting the height of the testing device on the support frame, the brightness of the light path at the corresponding height on the screen is tested. Based on the detected parameters, parameters such as the uniformity of planar brightness of the projected image, center brightness, and the stereoscopic contrast of the upper, middle, and lower multi-light paths are calculated. This results in high detection accuracy, more reliable test data, and more precise and efficient adjustment, solving the problem of low accuracy and efficiency in existing technologies that rely on visual judgment of screen illuminance.

[0005] To solve the above problems, the present invention provides: a contrast testing bracket, disposed between the projector and the back of the screen, comprising: Support frame; and, The testing device includes a mounting plate slidably mounted on a support frame, a flip motor fixed to one side of the mounting plate, a polarizer, an illuminance meter, and an illuminance meter integrating sphere light detector; the flip motor is connected to the polarizer and is used to drive the polarizer to flip up and down; the illuminance meter integrating sphere light detector is fixedly mounted between the polarizer and the mounting plate, and the illuminance meter is mounted below the illuminance meter integrating sphere light detector; two sets of the polarizer, the illuminance meter, and the illuminance meter integrating sphere light detector are provided.

[0006] Furthermore, the testing device also includes a fixed frame and a mounting block. The two polarizers are arranged side by side within the fixed frame, and one side of the upper end of the fixed frame is fixedly connected to the output shaft of the flip motor, resulting in more accurate measurements. The mounting block is fixed to the side of the mounting plate away from the flip motor, and the other side of the upper end of the fixed frame is rotatably mounted on the mounting block. This design is compact, easy to install, and facilitates simultaneous adjustment of the two polarizers during testing, leading to lower costs and higher efficiency.

[0007] Furthermore, a first detector is disposed above the output shaft of the flip motor, and a first sensing element is correspondingly disposed on the fixed frame. When the fixed frame is vertically positioned, the first detector and the first sensing element are communicatively connected. When the fixed frame is horizontal, the first detector is separated from the first sensing element, and the first detector is in a disconnected state, automatically switching the detection polarized light illuminance for higher efficiency.

[0008] Furthermore, the support frame includes a base, a first slide rail, a second slide rail, and a first fixing plate. The first slide rail and the second slide rail are vertically spaced at the upper end of the base, and the first fixing plate is used to fix the first slide rail and the second slide rail to the upper end of the base. One side of the back of the mounting plate is slidably connected to the first slide rail, and the other side of the back of the mounting plate is slidably connected to the second slide rail, making adjustment more convenient, the structure simpler, and the cost lower.

[0009] Furthermore, the first slide rail includes a slide rail body and a sliding track. The track is configured as a cylindrical structure to reduce the friction between the slider and the track, making adjustment easier. The side of the slide rail body that connects to the track is configured as a trapezoidal structure, and the width of the side of the slide rail body that contacts the track is smaller than the diameter of the track, so that the periphery of the slide rail body and the periphery of the track form a clamping groove. A slider is correspondingly provided on the back side of the mounting plate. A corresponding groove is provided on the side of the slider away from the mounting plate, and the track is disposed in the groove. The side edge of the trapezoidal side of the slide rail body is fitted and connected to the side wall of the open side of the slider, improving the stability between the slider and the first slide rail.

[0010] Furthermore, a second fixing plate is fixedly connected between the upper end of the first slide rail and the upper end of the second slide rail, further enhancing the stability of the support frame. The contrast test bracket also includes a lifting device, comprising a lifting motor, a drive wheel, a transmission wheel, a conveyor belt, and a connecting component. The lifting motor is fixed to the first fixing plate, and its output shaft is connected to the drive wheel. The transmission wheel is fixedly connected to the second fixing plate via bearings. The conveyor belt is fitted around the outer periphery of the drive wheel and the transmission wheel, and is meshed with them. One end of the connecting component is fixed to the conveyor belt, and the other end is fixed to the mounting plate. The lifting device allows for active height adjustment of the test device on the support frame, resulting in higher adjustment accuracy and more convenient operation.

[0011] Furthermore, a mounting strip is provided on the side of the support frame opposite to the mounting plate, and multiple positioning photoelectric sensors are spaced apart along the height direction on the mounting strip. These photoelectric sensors are used to monitor the longitudinal position of the testing device. A second sensing plate is provided on the corresponding side of the mounting plate, and the second sensing plate is electrically connected to the positioning photoelectric sensors, thereby improving the accuracy of control and making the test results more reliable.

[0012] Furthermore, the mounting strip has a mounting groove along its length, and the positioning photoelectric sensor is fixed in the mounting groove by a locking member, making installation and debugging more convenient.

[0013] Furthermore, the contrast testing bracket also includes a controller, which is communicatively connected to the testing device. The controller is equipped with multiple positioning switches for presetting the testing height of the testing device, an open button for controlling the polarizer to open, and a close button for controlling the polarizer to close, making operation simpler and more convenient, and improving testing efficiency.

[0014] Furthermore, the contrast testing bracket also includes a horizontal driving device, which comprises a horizontal adjustment motor, a horizontal transmission unit, and a guide rail. The lower end of the support frame is slidably mounted on the guide rail, the length of which is aligned with the length of the screen. The output shaft of the horizontal adjustment motor is connected to the horizontal transmission unit, and the output end of the horizontal transmission unit is connected to the support frame, driving the support frame and the testing device thereon to slide along the guide rail. This method is more time-saving and labor-saving, and the position adjustment accuracy and efficiency of the testing device are higher.

[0015] This utility model, by employing the aforementioned contrast testing bracket, offers the following advantages over existing technologies: This utility model relates to a contrast testing bracket, which is positioned between the projector and the back of the screen. It includes a support frame and a testing device. The testing device includes a mounting plate slidably mounted on the support frame, a flip motor fixed to one side of the mounting plate, a polarizer, an illuminance meter, and an illuminance meter integrating sphere light detector. The flip motor is connected to the polarizer and drives it to flip up and down. An illuminance meter integrating sphere light detector is fixedly mounted between the polarizer and the mounting plate, with the illuminance meter positioned below it. Two sets of each of the polarizer, illuminance meter, and illuminance meter integrating sphere light detector are provided. The mounting plate slidably mounts on the support frame, facilitating adjustment of the testing device's height to test the illumination of different light paths in the vertical direction of the screen. The polarizer measures the intensity distribution of natural and polarized light, the illuminance meter calculates the overall illumination intensity of the screen, and the illuminance meter integrating sphere light detector is used for single-point spectral analysis. Once all the light path tests on the screen are completed, the illuminance meter display results (including light intensity and spectral distribution) can be viewed. Then, the test conditions can be optimized or the parameters adjusted based on the test results. The operation is simple and efficient, and the measurement accuracy is high. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the embodiments are briefly introduced below. The drawings described below are only the corresponding drawings of some embodiments of this utility model.

[0017] Figure 1 This is a schematic diagram of one embodiment of the contrast testing bracket of this utility model.

[0018] Figure 2 for Figure 1 An enlarged schematic diagram of structure A in the middle.

[0019] Figure 3 for Figure 2 An enlarged diagram from another perspective.

[0020] Figure 4 This is a partially enlarged structural diagram of an embodiment of the connection position between the base and the slide rail of the contrast test bracket of this utility model.

[0021] Figure 5 This is a schematic diagram of one embodiment of the contrast testing bracket of this utility model.

[0022] Figure 6 This is a schematic diagram of the test state of an embodiment of the contrast test bracket of this utility model.

[0023] In the diagram: 1. Contrast test bracket; 11. Support frame; 111. Base; 112. First slide rail; 1121. Slide rail body; 1122. Track; 113. Second slide rail; 114. First fixing plate; 115. Second fixing plate; 116. Mounting strip; 117. Positioning photoelectric sensor; 12. Test device; 121. Mounting plate; 121a. Slider; 122. Flip motor; 123. Polarizer; 124. Illuminance meter; 125. Illuminance meter integrating sphere light detector head; 26. Fixed frame; 127. Mounting block; 128. First detector; 129. First sensor; 1210. Second detector; 1211. Second sensor; 13. Lifting device; 131. Lifting motor; 132. Drive wheel; 133. Transmission wheel; 134. Conveyor belt; 135. Connector; 14. Controller; 141. Upper button; 142. Middle button; 143. Lower button; 144. Open button; 145. Close button; 2. Projector; 3. Screen. Detailed Implementation

[0024] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0025] The directional terms mentioned in this utility model, such as "up", "down", "front", "back", "left", "right", "inner", "outer", "side", "top" and "bottom", are only for reference to the orientation of the accompanying drawings. The directional terms used are for the purpose of explaining and understanding this utility model, and are not intended to limit this utility model.

[0026] In the diagram, units with similar structures are represented by the same labels.

[0027] Please refer to Figure 1 , Figure 2 , Figure 3In this embodiment, the contrast testing bracket 1 is disposed between the projector 2 and the back of the screen 3, and includes a support frame 11 and a testing device 12. The testing device 12 includes a mounting plate 121 slidably disposed on the support frame 11, a flip motor 122 fixed to one side of the mounting plate 121, a polarizer 123, an illuminance meter 124, and an illuminance meter integrating sphere light detector 125. The flip motor 122 is connected to the polarizer 123 and is used to drive the polarizer 123 to flip up and down. The illuminance meter integrating sphere light detector 125 is fixedly disposed between the polarizer 123 and the mounting plate 121, and the illuminance meter 124 is disposed below the illuminance meter integrating sphere light detector 125. Two sets of polarizer 123, illuminance meter 124, and illuminance meter integrating sphere light detector 125 are provided.

[0028] The mounting plate 121 is slidably mounted on the support frame 11, facilitating the adjustment of the height of the testing device 12 to test the illumination of different light paths in the vertical direction of the screen 3. The polarizer 123 measures the intensity distribution of natural and polarized light, the illuminance meter 124 calculates the overall illumination intensity of the screen 3, and the illuminance meter integrating sphere light detector 125 is used for single-point spectral analysis. Once all the light paths to be tested on the screen 3 have been tested, the display results of the illuminance meter 124 (including illumination intensity and spectral distribution) can be viewed. Then, the test conditions can be optimized or parameters adjusted based on the test results. The operation is simple and efficient, and the measurement accuracy is high.

[0029] In this embodiment, please refer to Figure 2 , Figure 3 , Figure 5 The testing device 12 also includes a fixed frame 126 and a mounting block 127. Two polarizers 123 are arranged side by side within the fixed frame 126. One side of the upper end of the fixed frame 126 is fixedly connected to the output shaft of the flip motor 122, resulting in more accurate measurements. The mounting block 127 is fixed to the side of the mounting plate 121 away from the flip motor 122, and the other side of the upper end of the fixed frame 126 is rotatably mounted on the mounting block 127. The structure is compact and easy to install. Moreover, it is convenient to adjust the two polarizers 123 synchronously during testing, resulting in lower cost and higher efficiency.

[0030] Preferably, a first detector 128 is disposed above the output shaft of the flip motor 122, and a first sensing element 129 is correspondingly disposed on the fixing frame 126. When the fixing frame 126 is vertically disposed, the first detector 128 and the first sensing element 129 are communicatively connected. When the fixing frame 126 is horizontal, the first detector 128 is separated from the first sensing element 129, and the first detector 128 is in an open state, automatically switching the detection of polarized light illuminance, resulting in higher efficiency.

[0031] A second detector 1210 is also provided on one side of the first detector 128, and the second detector 1210 is tilted. When the fixed frame 126 is in a horizontal state, the first sensing plate 129 is electrically connected to the second detector 1210, and the fixed frame 126 rotates into place, resulting in higher control accuracy.

[0032] In this embodiment, please refer to Figure 1 , Figure 2 , Figure 4 The support frame 11 includes a base 111, a first slide rail 112, a second slide rail 113, and a first fixing plate 114. The first slide rail 112 and the second slide rail 113 are vertically spaced at the upper end of the base 111. The first fixing plate 114 is used to fix the first slide rail 112 and the second slide rail 113 to the upper end of the base 111. One side of the back of the mounting plate 121 is slidably connected to the first slide rail 112, and the other side of the back of the mounting plate 121 is slidably connected to the second slide rail 113, making adjustment more convenient, the structure simpler, and the cost lower.

[0033] Specifically, the first slide rail 112 includes a slide rail body 1121 and a sliding track 1122. The track 1122 is cylindrical to reduce the friction between the slider 121a and the track 1122, making adjustment easier. The side of the slide rail body 1121 that connects to the track 1122 is trapezoidal, and the width of the side of the slide rail body 1121 that contacts the track 1122 is smaller than the diameter of the track 1122, so that the periphery of the slide rail body 1121 and the periphery of the track 1122 form a clamping groove. A slider 121a is correspondingly provided on the back side of the mounting plate 121. A corresponding groove is provided on the side of the slider 121a away from the mounting plate 121, and the track 1122 is disposed in the groove. The side edge of the trapezoidal side of the slide rail body 1121 is in close contact with the side wall of the open side of the slider 121a, improving the stability between the slider 121a and the first slide rail 112. Furthermore, the angle design between the slide rail body 1121 and the track 1122 ensures a closer fit between the slider 121a and the first slide rail 112, thereby improving the verticality of the slider 121a and enhancing the stability of the structure and the accuracy of the test.

[0034] In this embodiment, please refer to Figure 1 , Figure 2 , Figure 4A second fixing plate 115 is fixedly connected between the upper end of the first slide rail 112 and the upper end of the second slide rail 113, further enhancing the stability of the support frame 11. To improve the convenience and efficiency of height adjustment of the testing device 12, the contrast testing bracket 1 also includes a lifting device 13. The lifting device 13 includes a lifting motor 131, a drive wheel 132, a transmission wheel 133, a conveyor belt 134, and a connecting member 135. The lifting motor 131 is fixed to the first fixing plate 114, and its output shaft is connected to the drive wheel 132. The transmission wheel 133 is fixedly connected to the second fixing plate 115 via bearings. The conveyor belt 134 is fitted around the outer periphery of the drive wheel 132 and the transmission wheel 133, and is meshed with them. One end of the connecting member 135 is fixed to the conveyor belt 134, and the other end is fixed to the mounting plate 121. The height of the testing device 12 on the support frame 11 is actively adjusted by the lifting device 13, resulting in higher adjustment accuracy and more convenient operation.

[0035] To accurately position the testing device 12, a mounting strip 116 is provided on the side of the support frame 11 opposite to the mounting plate 121. Multiple positioning photoelectric sensors 117 are spaced apart along the height of the mounting strip 116, used to monitor the longitudinal position of the testing device 12. A second sensing element 1211 is provided on the corresponding side of the mounting plate 121. The second sensing element 1211 is electrically connected to the positioning photoelectric sensors 117, improving control accuracy and making the test results more reliable.

[0036] Preferably, the mounting strip 116 has a mounting groove along its length, and the positioning photoelectric sensor 117 is fixed in the mounting groove by a locking member, making installation and debugging more convenient.

[0037] In this embodiment, please refer to Figure 1 The contrast test bracket 1 also includes a controller 14, which is communicatively connected to the test device 12. The controller 14 is equipped with multiple positioning switches for presetting the test height of the test device 12, an open button 144 for controlling the polarizer 123 to open, and a close button 145 for controlling the polarizer 123 to close, making operation simpler and more convenient and improving the efficiency of testing.

[0038] In this embodiment, the contrast test bracket 1 further includes a horizontal drive device, which comprises a horizontal adjustment motor, a horizontal transmission unit, and a guide rail. The lower end of the support frame 11 is slidably mounted on the guide rail, and the length direction of the guide rail is the same as the length direction of the screen 3. The output shaft of the horizontal adjustment motor is connected to the horizontal transmission unit, and the output end of the horizontal transmission unit is connected to the support frame 11, for driving the support frame 11 and the test device 12 on it to slide along the guide rail, which saves time and effort, and the position adjustment accuracy and efficiency of the test device 12 are higher. The horizontal drive structure is not shown in the figure, and the horizontal transmission unit can be set as a general gear, belt, or chain structure.

[0039] During actual testing, the user can remotely control the testing device 12 to perform testing operations via the buttons on the controller 14. Please refer to... Figure 6 During this test, the screen 3 was tested at three vertical heights: upper, middle, and lower. The positioning switch includes an upper button 141, a middle button 142, and a lower button 143, corresponding to the upper, middle, and lower test heights. Each test height has a corresponding positioning photoelectric sensor 117, improving testing efficiency. Pressing the upper button 141 rotates the lifting motor 131, driving the conveyor belt 134 to rotate, which in turn lowers the testing device 12 to the position of the positioning photoelectric sensor 117 corresponding to the upper height via the connecting piece 135. When the upper positioning photoelectric sensor 117 light illuminates, the lifting motor 131 stops rotating, and the test begins. The user presses the open button 144, and the polarizer is vertically set and in the open state, allowing for the measurement of the polarized light intensity on the screen 3. When the user presses the close button, the fixed frame 126 and its polarizer are rotated upwards by 90° under the action of the flip motor 122, making the fixed frame 126 horizontal. At this time, the intensity of natural light can be tested. Press the middle button 142 and the lower button 143 in sequence to test the light intensity at the middle and lower positions respectively. The specific testing method is the same as the testing steps for the upper and middle positions described above. After measuring the parameters at the upper, middle, and lower positions of a column, move the support frame 11 and its testing device 12 along the horizontal direction of the screen 3 using the horizontal drive device or manually, and test multiple columns of data sequentially. Finally, statistically compare all the measured data to determine the brightness of each position of the projector 2, and then adjust the emitted light of the projector 2 accordingly.

[0040] In this embodiment, the present invention relates to a contrast ratio testing bracket, which is disposed between the projector and the back of the screen. The bracket includes a support frame and a testing device. The testing device includes a mounting plate slidably mounted on the support frame, a flip motor fixed to one side of the mounting plate, a polarizer, an illuminance meter, and an illuminance meter integrating sphere light detector. The flip motor is connected to the polarizer and is used to drive the polarizer to flip up and down. An illuminance meter integrating sphere light detector is fixedly disposed between the polarizer and the mounting plate, and an illuminance meter is disposed below the illuminance meter integrating sphere light detector. Two sets of polarizers, illuminance meters, and illuminance meter integrating sphere light detectors are provided. The mounting plate is slidably mounted on the support frame, facilitating adjustment of the height of the testing device to test the illumination of different light paths in the vertical direction of the screen. The polarizer can measure the intensity distribution of natural light and polarized light, the illuminance meter can calculate the overall illumination intensity of the screen, and the illuminance meter integrating sphere light detector is used for single-point spectral analysis. Once all the light path tests on the screen are completed, the illuminance meter display results (including light intensity and spectral distribution) can be viewed. Then, the test conditions can be optimized or the parameters adjusted based on the test results. The operation is simple and efficient, and the measurement accuracy is high.

[0041] In summary, although the present invention has been disclosed above with reference to preferred embodiments, the above preferred embodiments are not intended to limit the present invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the scope defined in the claims.

Claims

1. A contrast testing bracket, disposed between the back of a projector (2) and a screen (3), characterized in that, include: Support frame (11); and, The testing device (12) includes a mounting plate (121) slidably mounted on the support frame (11), a flip motor (122) fixed to one side of the mounting plate (121), a polarizer (123), an illuminance meter (124), and an illuminance meter integrating sphere light detector (125). The flip motor (122) is connected to the polarizer (123) and is used to drive the polarizer (123) to flip up and down. The illuminance meter integrating sphere light detector (125) is fixedly arranged between the polarizer (123) and the mounting plate (121), and the illuminance meter (124) is arranged below the illuminance meter integrating sphere light detector (125). Two sets of the polarizer (123), the illuminance meter (124), and the illuminance meter integrating sphere light detector (125) are provided.

2. The contrast testing bracket according to claim 1, characterized in that, The testing device (12) further includes a fixed frame (126) and a mounting block (127). Two polarizers (123) are arranged side by side in the fixed frame (126). One side of the upper end of the fixed frame (126) is fixedly connected to the output shaft of the flip motor (122). The mounting block (127) is fixed to the side of the mounting plate (121) away from the flip motor (122). The other side of the upper end of the fixed frame (126) is rotatably mounted on the mounting block (127).

3. The contrast testing bracket according to claim 2, characterized in that, A first detector (128) is provided above the output shaft of the flip motor (122), and a first sensing plate (129) is correspondingly provided on the fixed frame (126). When the fixed frame (126) is vertically positioned, the first detector (128) is communicatively connected to the first sensing plate (129). When the fixed frame (126) is horizontal, the first detector (128) is separated from the first sensing plate (129), and the first detector (128) is in a disconnected state.

4. The contrast testing bracket according to claim 1, characterized in that, The support frame (11) includes a base (111), a first slide rail (112), a second slide rail (113), and a first fixing plate (114). The upper end of the base (111) is provided with the first slide rail (112) and the second slide rail (113) spaced apart in the vertical direction. The first fixing plate (114) is used to fix the first slide rail (112) and the second slide rail (113) to the upper end of the base (111). One side of the back of the mounting plate (121) is slidably connected to the first slide rail (112), and one side of the back of the mounting plate (121) is slidably connected to the second slide rail (113).

5. The contrast testing bracket according to claim 4, characterized in that, The first slide rail (112) includes a slide rail body (1121) and a sliding track (1122); the track (1122) is configured as a cylindrical structure, and the side of the slide rail body (1121) connected to the track (1122) is configured as a trapezoidal structure. The width of the side of the slide rail body (1121) in contact with the track (1122) is smaller than the diameter of the track (1122), so that the periphery of the slide rail body (1121) and the periphery of the track (1122) form a clamping groove; a slider (121a) is correspondingly provided on the back side of the mounting plate (121); a corresponding groove is provided on the side of the slider (121a) away from the mounting plate (121), and the track (1122) is disposed in the groove. The side of the trapezoidal side of the slide rail body (1121) is fitted and connected to the side wall of the opening side of the slider (121a).

6. The contrast testing bracket according to claim 4, characterized in that, A second fixing plate (115) is fixedly connected between the upper end of the first slide rail (112) and the upper end of the second slide rail (113); the contrast test bracket also includes a lifting device (13), which includes a lifting motor (131), a drive wheel (132), a transmission wheel (133), a conveyor belt (134), and a connecting piece (135); the lifting motor (131) is fixed on the first fixing plate (114), and the output of the lifting motor (131) is... The shaft is connected to the drive wheel (132); the transmission wheel (133) is fixedly connected to the second fixed plate (115) through a bearing; the conveyor belt (134) is fitted on the outer periphery of the drive wheel (132) and the transmission wheel (133) and is meshed with the drive wheel (132) and the transmission wheel (133); one end of the connector (135) is fixed to the conveyor belt (134) and the other end of the connector (135) is fixed to the mounting plate (121).

7. The contrast testing bracket according to claim 1, characterized in that, The support frame (11) has an installation strip (116) on the side away from the mounting plate (121). The installation strip (116) has a plurality of positioning photoelectric eyes (117) spaced apart along its height direction. The positioning photoelectric eyes (117) are used to monitor the longitudinal position of the test device (12). The mounting plate (1211) is provided on the side corresponding to the mounting plate (121). The second sensing plate (1211) is electrically connected to the positioning photoelectric eyes (117).

8. The contrast testing bracket according to claim 7, characterized in that, The mounting strip (116) has a mounting groove along its length, and the positioning photoelectric eye (117) is fixed in the mounting groove by a locking member.

9. The contrast testing bracket according to claim 1, characterized in that, The contrast test bracket also includes a controller (14), which is communicatively connected to the test device (12). The controller (14) is provided with a plurality of positioning switches for presetting the test height of the test device (12), an open button (144) for controlling the polarizer (123) to open, and a close button (145) for controlling the polarizer (123) to close.

10. The contrast testing bracket according to claim 1, characterized in that, The contrast test bracket also includes a horizontal drive device, which includes a horizontal adjustment motor, a horizontal transmission unit and a guide rail; the lower end of the support frame (11) is slidably disposed on the guide rail, and the length direction of the guide rail is the same as the length direction of the screen (3); the output shaft of the horizontal adjustment motor is connected to the horizontal transmission unit, and the output end of the horizontal transmission unit is connected to the support frame (11) for driving the support frame (11) and the test device (12) on it to slide along the guide rail.

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