GB/T 39798-2021Test methods for optical properties of glass used on multiple units (English PDF)

3.1 Secondaryimage

An image other than the original image of the light source or object that the observer sees through the sample from the driving position.

3.2 Secondary image deviates from secondaryimageseperation

When the observer observes through the sample from the driving position, the angular deviation between the original image of a distant light source or object and the brightest secondary image.

3.3 Angleofvisualdeformation

When observing an object through the sample at a certain angle, the observed object will be deformed. This angle is called the optical deformation angle.

Note: It is usually expressed by the angle of incidence (commonly known as the zebra angle).

4.1 Sample 1

The sample is a front window glass product.

4.2 Test method 1

The following two test methods should be used.

---Target test;

---The collimating telescope test.

Note: The collimating telescope test can obtain accurate secondary image deviation values.

4.3 Test environment 2

The test should be carried out in a dark room or dark place without disturbing light.

4.4 Target test 2

4.4.1 Test equipment

The test equipment consists of the following parts.

a) Target light source instrument. It is made of light box, the size of light box is about 300mm×300mm×150mm, and a suitable light source is used in the light box.

Ming, the inner surface is coated with matte white paint, and the front panel can be made of glass, the size is about 300mm×300mm, and the center is straight.

A circular hole with a diameter of 12mm is used to simulate the light source, and concentric rings are used to represent the deviation of the secondary image (5', 10', 15', 20' and 25').

Other parts of the front panel are painted with matt black paint or covered with opaque black paper. The schematic diagram is shown in Figure 1.

b) Sample holder. The sample can be placed according to the installation angle of the actual vehicle, and the sample can be rotated and moved in the horizontal and vertical directions.

4.4.2 Test procedure

The test is carried out according to the following steps.

a) Place the sample as shown in Figure 2.The distance between the sample and the target should not be less than 7m.

b) Rotate the sample in the horizontal direction so that the horizontal tangent line of the measured point is basically perpendicular to the observation direction, and the observer should be horizontal and vertical Move in the direction in order to observe the entire test area of the sample, as shown in Figure 3.The distance between the observer and the sample should be as close as possible to the actual driver The distance between the seating position and the glass.

c) Observe through the sample and record the position of the outermost edge of the secondary image of the simulated light source in the center of the target light source on the target, as shown in Figure 4.In order to observe It is clear and can be observed through a single-tube telescope.

5.3 Slash method

5.3.3 Test data processing

The optical distortion value of the sample is the maximum distance delta between the lower edge of the deformed projection line and the upper edge of the ruler.

5.4 Grid method 9

5.4.1 Test equipment

The test equipment shall at least consist of a camera, a camera holder, a sample holder, a lighting lamp and a grid target board. The test principle is shown in Figure 11 Shown. The test equipment requirements are as follows.

a) Camera. It should be able to take clear pictures. Digital camera pixels are generally no less than 20 million. The distance between the test and the sample l1 is 1.5m.

b) Camera bracket. It should have a level or equivalent indicator, and can realize the camera to rotate in three-dimensional space.

c) Sample support. adjustable support that can be adjusted according to the specified test angle or fixed support that meets the actual installation angle can be used. frame. During the test, the distance l2 from the grid target board is 3.0m.

d) Lighting lamp. It should have enough brightness to make the shooting clear, and the luminous flux is generally not less than 4500lm.

e) Grid target board. the size is not less than 2.5m×3.5m. Lines arranged vertically and horizontally on the surface form a side length of 25.4mm±0.1mm Square grid pattern. The diameter of the straight line should be 0.5mm~1.0mm. The bottom plate color and line color of the grid target plate should have There is enough color difference to distinguish, usually the bottom plate is black and the lines are white.

5.4.2 Test procedure

The test is carried out as follows.

a) Dip a clean silk cloth with a detergent that has no corrosive effect on the sample, and wipe the surface of the sample until there is no visible stain.

b) Fix the sample on the test stand and adjust the test stand until the sample reaches the specified test angle.

c) Turn on the illuminating lamp, the light source is facing the grid target board, adjust the position and brightness of the illuminating lamp until the entire grid target board is evenly illuminated.

d) Fix the camera on the camera bracket, adjust the camera bracket so that the camera is horizontal and the camera lens is vertical Grid target board.

e) Push the sample to the specified position, adjust the focus and aperture of the camera to make the grid clear, and then take a picture of the grid target through the sample The case should include part of the grid target pattern outside the sample. If one shot cannot cover the entire area of the sample that needs to be tested, then Keep the camera shooting angle unchanged, you can move the camera up, down, left, and right to take multiple shots to cover the sample. All areas tested.

f) Find out the grid lines that are bent and deformed in the grid target pattern of the sample through the sample, and draw tangent lines at the bent and deformed places. If it bends If the grid line of the shape is in the horizontal direction, the tangent is as shown in Figure 12a); if the grid line of the bending deformation is in the vertical direction, the tangent is As shown in Figure 12b).

g) The value of optical distortion is represented by the maximum slope of the tangent. Extend the tangent to the undeformed grid area outside the sample for calculation. If tangent Derived from a grid line that is bent and deformed in the horizontal direction, the slope of the tangent is determined by the tangent crossing a complete vertical grid.

The number of horizontal grids required is represented by n, as shown in Figure 13a). If the tangent line comes from the grid line that is bent and deformed in the vertical direction, Then the slope of the tangent is represented by the number of vertical grids n required for the tangent to cross a complete horizontal grid, as shown in Figure 13b)

Shown. Compare the above slope values and take the maximum value as the optical distortion value of the sample, expressed as 1.n, where n is a positive integer.

5.4.3 Test data processing

The optical distortion value is expressed by the maximum slope of the tangent, expressed as 1.n, where n is a positive integer.

5.5 Round spot method 11

5.5.1 Test equipment

The test equipment should consist of the following parts.

a) Except for the slides, everything else is the same as 5.3.1.

b) Slide. The projected image is an array of round spots on a dark background. The quality and contrast of the slide should meet the test requirements to facilitate the measurement

5.5.2 Test environment

The test should be carried out in a dark room or dark place without disturbing light.

5.5.3 Test procedure

The test is carried out as follows.

a) Place the projector, sample, and screen as shown in Figure 9, l1=l2=4000mm±100mm.

b) Make sure that the diameter of the round spot on the screen is D (mm) when there is no sample. When l1=l2=4000mm, according to formula (2), D It is 8mm.

c) Place the sample on the sample holder at the mounting angle of the actual vehicle.

d) Rotate the sample in the horizontal direction to ensure that the horizontal tangent of the measured point is basically perpendicular to the observation direction, and move in the horizontal and vertical directions.

Move to observe the entire test area and determine the maximum deformation of the round spot projected on the screen. The schematic diagram of the maximum deformation is shown in the figure.

As shown in 15, denoted as deltad, deltad is calculated according to formula (3). deltad=max(|D1-8|,|D2-8|) (3)

Figure 15 Schematic diagram of the maximum deformation of the round spot

e) From the measured maximum deformation deltad, calculate the maximum value of optical distortion according to formula (4), and the result is kept to 1 decimal place. deltad 0.29l2 (4) Where. deltaalpha---optical distortion, the unit is minutes (');

deltad---Maximum deformation, in millimeters (mm); l2 ---The distance from the sample to the screen, in millimeters (mm).

5.5.4 Test data processing

The optical distortion is the value calculated by equation (4).

6.1 Sample 12

The samples are glass products or test pieces. If the test piece is used, its size should not be less than 100mm×100mm, and it should be consistent with the product.

Have the same material, structure and manufacturing process. The test piece can also be cut directly from the corresponding test area on the product.

6.2 Test equipment 12

The haze meter should meet the requirements of GB/T 2410, and the mixed light output from the light source and the light detector becomes the C light source after being filtered. Can also be used with It is equivalent to any optical system. The principle of the haze meter is shown in Figure 16.

6.3 Test procedure 13

The test is carried out as follows.

a) Dip a clean silk cloth with a cleaning agent that has no corrosive effect on the sample, and wipe the surface of the sample until there is no visible stain;

b) Turn on the power of the instrument, and perform preheating according to the required preheating time of the instrument until the instrument is stable;

c) When the instrument is stable, the transmittance value should be 100, and the haze value should be 0;

d) Put the sample into the instrument and adjust the angle of the sample to make its surface close to the entrance window of the integrating sphere;

e) Press the instrument test button, the instrument will act according to Table 2, and read and record four indications;

f) For equipment without a built-in haze calculation program, the haze is calculated according to formula (5), and the result is accurate to 0.1%; for a built-in haze meter Calculate the program equipment, directly read the haze.

7.1 Sample 13

The samples are glass products or test pieces. If the test piece is used, its size should not be less than 100mm×100mm, and it should be consistent with the product.

Have the same material, structure and manufacturing process. The test piece can also be cut directly from the corresponding test area on the product.

7.2 Test equipment 13

The test equipment is the same as 6.2.

7.3 Test procedure 13

The test is carried out as follows.

a) Follow the steps in 6.3a)~e) to read and record the two indications of tau1 and tau3;

b) For devices without a built-in transmittance calculation program, the transmittance is calculated according to formula (6), and the result is accurate to 0.1%; for devices with built-in transmittance The device of the light rate calculation program directly reads the light transmittance.

7.4 Test data processing 14

The light transmittance is calculated according to formula (6).

8.1 Sample 14

The test sample is a glass product.

8.2 Test equipment 14

The test equipment contains parts.

a) A screen with black and white stripes, and the brightness is uniform, the width of the black and white stripes is 25mm, and the inclination angle is 45°;

b) Sample holder. The sample can be placed vertically and can be rotated around the center.

8.3 Test procedure 14

The test is carried out as follows.

a) The sample is placed vertically at a distance of 4.5m from the screen (see Figure 17).

b) Place the sample at the position of 6 in Figure 17;

c) The observer is 4.5m away from the sample;

d) Slowly rotate the sample clockwise while observing the deformation of the screen stripes;

e) Continuously rotate the sample until the screen fringe deformation disappears, stop rotating the sample, and record the incident angle alpha at this time.