Diopter:

When light is incident from one object to another material with different optical densities, the propagation direction of the light is deflected. This phenomenon is called refraction, and the unit of the size (refractive power) of this refraction phenomenon is diopter. (abbreviated as "D"). 1D power is equivalent to focusing parallel light rays at a focal length of 1 meter. The stronger the refractive power, the shorter the focal length. The focal length of the lens for 2D power is 1/2m or 50cm. If you want to know the focal length of the lens, divide the diopter power by 100cm, which is 1.00m, and the result is the diopter. For example, the focal length of 5D power is 20cm. (100cm divided by 5D=20cm.) The refractive power of a convex lens is represented by a "+" sign, and the refractive power of a concave lens is represented by a "-". 1 diopter or 1D equals 100 degrees

gain:

The magnification of an angle of observation of an object with the naked eye and the angle magnification of the same object observed by a telescope at the same location

Resolution:

Generally, the parameter expressed in lin/mm is as large as possible, indicating the number of lines seen per millimeter

Exit pupil distance:

The exit pupil distance is the distance between the eye and the last lens of the eyepiece to be able to see the entire field of view.

Exit pupil diameter: The diameter of the bright spot formed behind the eyepiece after the light rays converge through the eyepiece.

For the optical equipment used by the naked eye, the light must pass through the pupil and enter the retina for imaging. The human pupil is about 3 mm in the daytime and up to 7 mm at night. When observing with optical equipment, the bright spot formed by the converging light of the eyepiece will be projected on the pupil. Therefore, the larger the diameter of the exit pupil, the brighter the image will be. But an exit pupil diameter larger than the pupil diameter is meaningless.

waterproof level:

The waterproof level of an electronic measuring instrument reflects the moisture-proof and dust-proof ability of the instrument, especially for outdoor activities, where the rabbit cannot be in a harsh environment with high humidity or dusty sand. Longevity matters. To this end, the IEC529 standard is formulated internationally. In order to adapt to this, the waterproof protection of electronic instruments is divided into 10 grades in the Japanese Industrial Standard, which are represented by IPX1, IPX2...

(1) IPx 1

Method name: vertical drip test

Place the sample on the rotating sample stage at 1r/min according to the normal working position of the sample, and the distance from the top of the sample to the drip port is not more than 200mm.

Test conditions: dripping volume of 10.5 mm/min Duration: 10 min

(2) IPx 2

Method name: dripping test at 15° inclination

Make one face of the sample at an angle of 15° to the vertical, and the distance from the top of the sample to the drip port is not more than 200mm. After each test, switch to another side, a total of four times.

Test conditions: The amount of dripping water is 30.5 mm/min Duration: 4 × 2.5 min (10 min in total)

(3) IPx 3

Method name: Select a pendulum tube with an appropriate radius for the water spray test, so that the height of the sample table is at the diameter of the pendulum tube, and the sample is placed on the sample table so that the distance from the top to the sample water nozzle is not greater than 200mm, and the water flow rate is The number of water spray holes in the swing pipe is calculated, and each hole is 0.07 L/min. When water is sprayed, the water spray holes in the 60° arc sections on both sides of the midpoint of the swing pipe are sprayed to the sample. The sample to be tested is placed in the center of the semicircle of the pendulum tube. The swing tube swings 60° on both sides of the vertical line, a total of 120°. Each swing (2×120°) about 4s

Test time: continuous watering for 10 minutes

b. Sprinkler water spray test

Hand-held spray water splash test device, so that the parallel distance from the top of the test to the nozzle of the hand-held sprinkler is between 300mm and 500mm.

During the test, a baffle with a counterweight should be installed, and the water flow should be 10 L/min.

Calculated according to the surface area of the shell of the tested sample, 1 minute per square meter (excluding installation area), at least 5 minutes

(4) IPx4

Method name: splash test

a. Swing tube splash test

The water spray area is the water spray from the water spray holes in the 90° arc segments on both sides of the midpoint of the pendulum tube sprayed to the sample. The sample to be tested is placed in the center of the semicircle of the pendulum tube. The swing tube swings 180° on both sides of the vertical line, a total of about 360°. Each swing (2×360°) takes about 12s b. Nozzle Splash Test

Test equipment and sample placement: the same as the above IPX 3 paragraph b;

Remove the baffles with counterweights installed on the equipment, 1 minute per square meter (excluding installation area) at least 5 minutes

(5) IPx 5

Method name: water spray test

The inner diameter of the spray nozzle of the nozzle is 6.3mm, and the distance from the test sample to the spray nozzle is 2.5m ~ 3m, and the water flow rate is 12.5 L/min (750 L/h)

Calculated based on the surface area of the shell of the sample to be tested, 1 minute per square meter (excluding installation area) at least 3 minutes

(6) IPx6

Method name: Intense water spray test; the inner diameter of the spray nozzle of the nozzle is 12.5 mm

The distance from the test sample to the water jet is 2.5m ~ 3m, and the water flow is 100 L/min (6000 L/h) for at least 3 min.

(7) IPx 7

Method name: short-time immersion test

Test equipment and test conditions: immersion tank. The dimensions shall be such that the distance from the bottom of the sample to the water surface is at least 1 m after the sample is placed in the immersion tank. The distance from the top of the sample to the water surface is at least 0.15m

Test time: 30 min

(8) IPx8

Method name: continuous diving test;

Test equipment, test conditions and test time: to be agreed by the supply and demand (buyer and seller) parties, the severity should be higher than IPX 7

LABEL: Night vision device

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