Automated testing apparatus for screen alignment

• US 4,897,721 A
• Filed: 05/16/1988
• Issued: 01/30/1990
• Est. Priority Date: 05/16/1988
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Apple Computer Incorporated (Apple Inc.)
• Inventors: Young, Stephen J., Blackwell, Mike K., Dowling, Kevin J., Moravec, Hans P., Zajicek, Lada
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): Kostak, Victor R.
• Application Number:
  US07/194,497
• Time in Patent Office: 624 Days
• Field of Search: 358/139, 358/10, 358/245, 358/255, 358/903, 340/707, 364/559, 324/121 R, 324/404, 315/377, 315/372, 315/386
• US Class Current: 348/190
• CPC Class Codes: H04N 17/04 for receivers

Abstract

The present invention is an automated testing apparatus and process for screen alignment involving a pattern generator, sensors, and an analysis computer. Two sets of patterns are displayed on the screen being tested. Sensors are used to observe patterns on the screen. An analysis computer receives the data from these observations and then compares the observed data to data from an ideal screen to determine the screen'"'"'s alignment parameters.

Claims

1. An automated testing apparatus for screen alignment of a video display screen comprising:

display generation means, coupled to a video screen to be tested, for generating predetermined patterns on said screen;

sensing means, coupled to said screen, having a plurality of sensors prepositioned and fixedly mounted in a sensor plate for sensing said predetermined patterns on said screen;

computing means, coupled to said sensing means, for receiving test data from said sensors and comparing said test data to data from an ideal screen such that the results of said comparison determine parameters for evaluating screen alignment and distortion.

2. The automated testing apparatus described in claim 1 wherein said display generation means includes a program running on a computer that is coupled to said screen.

3. The automated testing apparatus described in claim 1 wherein said display generation means is a video controller.

4. The automated testing apparatus described in claim 1 wherein said sensing means is further comprised of:

synchronization means, coupled to said computing means, for sequencing the transmission of data; and

photo sensing means, coupled to said computing means, for signaling the presence or absence of photo-emissions from said screen.

5. The automated testing apparatus described in claim 4 wherein said synchronization means is further comprised of:

an analog-to digital converter;

a threshold and filter circuit coupled to said photo sensing means and to said analog-to- digital converter, such that an analog photo-sensed signal is filtered for analog-to-digital conversion by said analog-to-digital converter.

6. The automated testing apparatus described in claim 5 wherein said photo sensing means is comprised of photo transistors.

7. The automated testing apparatus described in claim 6 wherein said computing means displays the results of said comparison on a second video screen.

8. The automated testing apparatus described in claim 7 wherein said computing means records and stores the results of said comparison in a storage device.

9. A method for testing alignment of a video display screen , comprising the steps of:

positioning a plurality of photo sensors over said screen;

generating a first predetermined pattern on said screen for detection by said sensors in order to locate higher order coordinates corresponding to locations of said sensors;

generating a second predetermined pattern on said screen for detection by said sensors in order to locate lower order coordinates corresponding to locations of said sensors;

analyzing sensed data produced by said sensors by comparing said sensed data to predefined values to determine screen alignment characteristics of said screen.

10. The method of claim 9 further comprising the step of displaying the results of said analyzing step, said displaying step occurring after said analyzing step.

11. The method of claim 10 wherein a timing pattern is displayed on a predetermined section of said screen, such that at least one of said sensors provides timing data.

12. The method of claim 11 wherei nsaid step of analyzing is performed by using a least sum of the squares fit analysis technique.

13. The method of claim 12 wherein said displaying step is further comprised of graphically presenting the results of the analysis.

14. The method of claim 13 wherein said displaying step further comprises recording the results of the analysis in a memory.

15. An apparatus for testing screen alignment of a video display screen, comprising:

display generation means coupled to said display screen for generating predetermined patterns on said screen;

a sensor panel comprised of;

(a) a plurality of vacuum suction devices for coupling said sensor panel over said screen; and

(b) a plurality of sensor photo transistors for sensing at least a first and second patterns on said screen, wherein at least one of said plurality of photo transistors is used for sensing a timing sequence of said patterns;

a threshold and filter circuit coupled to said sensor photo transistors, such that an analog photo sensed signal sensed by said transistors is filtered;

an analog-to digital converter coupled to said threshold and filter circuit for converting said analog photo sensed signal to a digital signal;

a processor coupled to said analog-to-digital converter and having a resident analysis program that compares test data received from said sensor panel to predetermine ideal screen alignment data

to determine misalignment of said screen.

16. A method for testing alignment of a video display screen, comprising the steps of:

positioning a sensor plate comprising a plurality of fixedly mounted photo sensors over said screen;

generating a display using a series of predetermined patterns on said screen to be sensed by said sensors, wherein said predetermined patterns are comprised of a series of Gray code patterns for coarse positioning of said sensors and a series of pixels-wide bar patterns for fine positioning of said sensors;

analyzing outputs of said sensors by comparison to predefined ideal screen parameters to determine screen alignment characteristics of said screen.

17. The method of claim 16 wherein said predetermined patterns are sensed by said sensors which then indicate positions of said sensors relative to said predetermined patterns.

18. The method of claim 17 wherein said step of analyzing by comparison is performed using a least sum of the squares fit analysis technique.