Why light reflected off of my calculator screen turns bluish?

In summary, the conversation discusses the phenomenon of dichroism, which is the effect of different wavelengths of light passing through layers of transparent materials and causing interference. This effect can be seen in everyday objects like LCD screens and can also produce stunning colors in nature, such as on the wings of birds and insects. The conversation also mentions the relationship between dichroism and polarization of light.
  • #1
nuclearfireball_42
9
2
So, I was in class listening to my lecturer when I notice something intriguing. I was looking at the reflection of a lamp on the screen of my calculator. I paid close attention to the colour of the light reflected of my calculator and realized that when I rotate my calculator by about 90 deg, the colour of the lamp reflected off of it changes colour gradually from blue to purple. The colour that I see with my eyes and through the pics I took here is almost the same.

As you can see the colour of the light reflected off is bluish here
IMG20190920090649.jpg


But here when rotated clockwise at about 90 deg, the colour of the light reflected looks purplish
IMG20190920090659.jpg


I'm just wondering whether or not this has something to do with the polarization of the light wave. Anybody has any explanation as to why light behave this way given this circumstance?
 
Science news on Phys.org
  • #2
The effect is called dichroism.
 
  • #3
trurle said:
The effect is called dichroism.
Will look it up. Thanks!
 
  • #4
trurle said:
The effect is called dichroism.
Dichroism is a term to describe the effect when light of different wavelengths passes through layers of different transparent materials. There are always reflections at any interface and the multiple reflections at several layers - like air over a thin oil film, floating on water. The different wavelengths will have different phase shifts through the layers (same delay but different shifts) and that will cause different results of the interference- producing maxes and mins for different wavelengths in any given angle. The effect can be strong or mild. The LCD screen produces a mild colouration whereas the layers on a bird or insect's wing can produce stunning effects due to selectivity of different wavelengths. The colours can be a lot stronger and more noticeable than what you could ever get with a simple glass prism or a pigment.
The Polarising layers in an LCD produce the effect as an unwanted byproduct. The more you pay, the better they tend to be. Note how a bit of pressure on the glass (careful) can cause colour fringes.
 
  • Like
Likes nuclearfireball_42

1. Why does light reflected off of my calculator screen turn bluish?

The bluish color of light reflected off of a calculator screen is due to a phenomenon called selective reflection. This means that only certain wavelengths of light, in this case blue light, are being reflected off of the surface of the calculator screen while the rest of the colors are being absorbed.

2. Is the bluish color of reflected light from my calculator screen harmful?

No, the bluish color of light reflected off of a calculator screen is not harmful. It is simply a result of the materials used in the screen and the way light interacts with them. It does not emit any harmful radiation or cause any damage to the eyes.

3. Can the bluish color of reflected light change depending on the angle of the calculator screen?

Yes, the angle of the calculator screen can affect the color of reflected light. This is because the angle of incidence, or the angle at which light hits the surface, can change the way light is reflected. This is known as the angle of reflection and can cause the color of reflected light to shift slightly.

4. Why does light reflected off of a calculator screen appear brighter than the surrounding environment?

The brightness of reflected light from a calculator screen is due to the high reflectivity of the materials used in the screen. The screen is designed to reflect as much light as possible, making it appear brighter than the surrounding environment where light is being absorbed by other surfaces.

5. Can the bluish color of reflected light be used for any practical purposes?

Yes, the bluish color of reflected light can be used for practical purposes such as in LCD screens. The blue light is combined with red and green light to create different colors on the screen. Additionally, the selective reflection of blue light can also be used in polarizing filters to reduce glare and improve visibility.

Similar threads

  • Optics
Replies
2
Views
1K
Replies
2
Views
927
Replies
12
Views
1K
Replies
6
Views
5K
Replies
1
Views
2K
Replies
5
Views
1K
Replies
4
Views
4K
  • Introductory Physics Homework Help
Replies
3
Views
320
  • Electromagnetism
Replies
8
Views
1K
Replies
4
Views
686
Back
Top