The role of blackboard lights
The classroom did not set up special lamps for the blackboard, or used ordinary fluorescent lamp brackets as the blackboard lights, so most of the lights were not really effectively applied to the blackboard, but went to the center outside the blackboard. With insufficient illumination on the blackboard and poor average illumination, students naturally cannot see what is written on the blackboard.
In addition, the dazzling glare from exposed fluorescent tubes can make it difficult for students to concentrate, which can reduce learning efficiency and easily cause eye diseases such as myopia.
The blackboard lights for classrooms are different. The blackboard lamp with asymmetric light distribution characteristics is used for projection, and the reasonable planning of the lighting device makes the brightness of the entire blackboard evenly distributed. When students read the content written on the blackboard, the visual experience is better, and no glare is generated.
In addition to choosing professional lighting fixtures, the location of the blackboard lamp is also very important. If the location of the device is not suitable, the blackboard lighting will also have uneven illuminance, reflection, glare and other undesirable phenomena. According to "Hygienic Code for Daylighting and Lighting in Primary and Secondary School Classrooms-GB-7793-2010",
The blackboard lighting needs to do the following:
1) In order to prevent the reflection of glare to the students, the installation position of the blackboard lamps should be: the first row of students see the top of the blackboard, and use this field of vision to reflect to the ceiling to obtain the image point interval L1, and use the dot P and the top of the blackboard as a dotted line When connecting, the lamps should be installed in the area above the connecting dotted line.
2) The lamps should not be arranged where the teacher stands within the 45° elevation angle of the field of view of the podium, that is, the distance between the lamps and the blackboard should not be greater than L2.
3) In order to ensure sufficient average degree of the blackboard, the light axis of the lamp should preferably be incident on the center line of the blackboard at 55°, or the aiming point of the optical axis of the lamp should be moved down to the bottom 1/3 of the interval blackboard.
