1. Digital Displays Cathode Ray Tubes Flat Panel Displays
Lecture 7: Displays
Digital Displays
Cathode Ray Tubes
Flat Panel Displays
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

2. Summary of What We Have Learned
Ohm’s Law
Resistor Combinations
What a Diode Does
Transistors as Switches
Op-Amp Configurations
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

3. Introduction to Engineering Electronics
Ohm’s Law
Kirchoff’s Voltage Law
Kirchoff’s Current Law
Series Equivalent
Parallel Equivalent
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

4. Diode V-I Characteristic
For ideal diode, current flows only one way
Real diode is close to ideal
Ideal Diode
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

5. Introduction to Engineering Electronics
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

6. Introduction to Engineering Electronics
Op-Amp
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

7. Ideal Op-Amp Continued
Bandwidth is also infinite. Thus, an ideal op-amp works the same at all frequencies.
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

8. Golden Rules for Op-Amps
The output attempts to do whatever is necessary to make the voltage difference between the two inputs zero. (Negative Feedback is Required)
The inputs draw no current.
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

9. Op-Amp Configurations
Buffer or Voltage Follower
No voltage difference between the output and the input
Draws no current, so it puts no load on the source
Used to isolate sources from loads
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

10. Op-Amp Configurations
Non-Inverting Amplifier
Note that this formula is different in the lab write up
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

11. Op-Amp Configurations
Inverting Op-Amp
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

12. Introduction to Engineering Electronics
Binary Numbers
0 0000
1 0001
2 0010
3 0011
4 0100
5 0101
6 0110
7 0111
8 1000
9 1001 =
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

13. Astable and Monostable Multivibrators
What are they good for?
Astable: clock, timing signal
Monostable: a clean pulse of the correct height and duration for digital system
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

14. Introduction to Engineering Electronics
555 Timer
The correct frequency is given by
Note the error in the figure
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

15. From What We Have Seen So Far, How Would We Make a Display?
LEDs in some kind of an array
How to arrange them?
How to control them?
What is the purpose of the display?
How much should it cost?
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

16. Introduction to Engineering Electronics
7 Segment Displays
Binary inputs are converted to a decimal number display by turning on a set of 7 LEDs
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

17. Introduction to Engineering Electronics
7 Segment Displays
Common cathode at the right and common anode at the left
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

18. Introduction to Engineering Electronics
7 Segment Displays
This is the 0-9 counting circuit you will be building in the lab.
Note that it has to count and then convert the binary to show decimal
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

19. Displays Applications
7 Segments are excellent for displaying simple alphanumeric information – multimeters, clocks, etc.
More complex displays are needed to show images – computer displays, televisions, etc.
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

20. 2 Minute Quiz Name________________ Sec___
Give three examples of electronic displays
What is a pixel?
True or False
Blue light is higher energy than red light
Most colored light is not produced directly
Solid state light is generally produced directly
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

21. Dividing Images Into Pixels
Second image is blown up many times to show the individual pixels
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

22. Dividing Images Into Pixels
The second image is blown up a bit less but pixels are still obvious
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

23. Dividing Images Into Pixels
The second image is sampled more coarsely
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

24. Dividing Images Into Pixels
Black and white or single color displays are easier to implement
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

25. Dividing Images Into Pixels
Images can be constructed by scanning across them, line-by-line
The original image is encoded in this manner (e.g. this is the way a scanner or copier works) by, say, starting at the upper left and going line by line to the lower right
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

26. Introduction to Engineering Electronics
Plasma Displays
Large, bright, flat panel display
View from a wide angular range
Designed for HDTV
Available from many companies
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

27. Introduction to Engineering Electronics
Plasma Displays
High voltage discharge creates high energy photons (UV) that excite phosphors
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

28. Introduction to Engineering Electronics
Plasma Displays
Note the patterns of the address and display electrodes
To excite an address, both voltages must be applied
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

29. Introduction to Engineering Electronics
Plasma Displays
Fujitsu ALIS display
More complex electrodes but better use of surface area for display
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

30. Introduction to Engineering Electronics
Plasma Displays
Discharge region geometry and voltages
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

31. Introduction to Engineering Electronics
Displays: CRT
In a CRT, an electron beam excites the phosphor rather than a UV photon
The beam is directed to a spot on the surface using sweep plates
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

32. Introduction to Engineering Electronics
Displays: CRT
Three separate electron guns are required to produce a color picture
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

33. Introduction to Engineering Electronics
Displays: CRT
At the left is the layout of the mask and phosphors
At the right is the scanning sequence
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

34. Introduction to Engineering Electronics
Displays: CRT
A large variety of configurations are used by manufacturers
Look carefully at the screen of your TV
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

35. Introduction to Engineering Electronics
Image From My TV
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

36. Same Image Enlarged to Show Screen
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

37. Same Image Enlarged Further
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

38. Same Image Enlarged Further
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

39. Unsmoothed Image Enlarged Further
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

40. Introduction to Engineering Electronics
Displays: Early TV
Allen Dumont
B.S.E.E. RPI 1924
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

41. Introduction to Engineering Electronics
Displays: Dumont
Developed the first practical CRT (previous versions lasted only 10s of hours)
First company to market home TV receiver in 1938 (previous slide)
Dumont network until 1956 – It could not compete with radio networks (poorly funded)
Broadcast Jackie Gleason, first sporting events, but shows were bought by big 3 networks
Dumont was one of broadcastings first millionaires
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

42. Where Will You See This Material Again?
7 Segment Displays: Many courses
CRT: ECSE-2100 Fields and Waves I
Digital Imaging: ECSE-4540 Voice and Image Processing
RF Circuitry: ECSE-4060 Communications Circuits
Plasmas: ECSE-4320 Plasma Engineering
Optics: ECSE-4630 Lasers and Optical Engineering and ECSE-4640 Optical Communications and Integrated Optics
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

43. Introduction to Engineering Electronics
Imaging Tools
Mathworks Image Processing Toolboxes
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor

44. Charged Particle Accelerators
Fermilab
Medical Accelerator
17 September September 2018
Introduction to Engineering Electronics
K. A. Connor