Answer: C: 90-120° or F: 30-60°
Answer analysis: When discussing the emitting angle of LED square plug-in lamp beads, we need to consider the impact of its shape on light distribution. The square design may mean that the light distribution in the horizontal and vertical directions is relatively uniform, but the specific emitting angle still depends on factors such as the packaging method of the lamp beads, the design of the lens or reflector cup.
Now, let's analyze one by one according to the given options:
A: 15-20°: This range is usually related to highly concentrated LED lamp beads and may not be applicable to square plug-in lamp beads, because the square design may be more inclined to provide a wider light distribution.
B: 90°: It is difficult for a single angle value to accurately describe the emitting characteristics of LED square plug-in lamp beads, because their emitting angles may vary depending on the design and packaging method, and it is unlikely to be limited to 90°.
C: 90-120°: This range may be applicable to some LED square plug-in lamp beads, especially those designed to provide medium to wide light distribution. However, it may not be a universal emitting angle for all square plug-in lamp beads.
D: 120°: Although the luminous angle of some LED lamp beads may be close to 120°, this single value may not be sufficient to fully describe the luminous characteristics of the direct-plug square lamp beads.
E: 120-140°: This range is more inclined to the luminous range of large angles, which may not be the typical luminous angle of direct-plug square lamp beads unless there are special considerations in the design.
F: 30-60°: This range is relatively moderate, and considering that the square design may produce a relatively uniform distribution effect on the light, this range may be more in line with the common luminous angles of some LED direct-plug square lamp beads. However, it should also be noted that lamp beads with different designs and packaging methods may be different.
Since the luminous angle of LED direct-plug square lamp beads may vary depending on the specific design and application, there is no absolute answer that applies to all situations. But based on general LED lamp bead design experience and optical principles, we can reasonably speculate that option C (90-120°) or option F (30-60°) may be closer to the luminous angle range of some direct-plug square lamp beads. However, if one must choose a more likely range, option C (90-120°) may be closer, considering that the square design may tend to provide a relatively uniform and wide light distribution.
But please note that this is only a general guess, and the actual light angle needs to be determined based on the specific product.
Therefore, if one must choose an answer, option C (90-120°) may be the closest. But it is also necessary to recognize that this is not absolute, and the specific situation still needs to be analyzed.