Liquid crystal video projector having lamp and cooling control and remote optics and picture attribute controls

• US 5,136,397 A
• Filed: 12/23/1991
• Issued: 08/04/1992
• Est. Priority Date: 10/31/1989
• Status: Expired due to Fees

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: Miyashita, Kiyoshi
• Primary Examiner(s): Groody, James J.
• Assistant Examiner(s): Powell, Mark R.
• Application Number:
  US07/814,330
• Time in Patent Office: 225 Days
• Field of Search: 353/52-61, 353/85, 353/101, 352/139, 352/140, 352/198, 352/202, 352/203, 358/194.1, 358/231, 358/232, 358/236, 358/60, 315/200 R, 315/209 R, 315/129, 315/133, 315/134, 315/225
• US Class Current: 348/748
• CPC Class Codes: H04N 2005/745 Control circuits therefor
• CPC Class Codes: H04N 5/445 for displaying additional information H04N5/50 takes precedence
• CPC Class Codes: H04N 5/60 for the sound signals
• CPC Class Codes: H04N 5/7441 the modulator being an array of liquid crystal cells

Abstract

A video projection system having a liquid crystal panel with a video image, a projection lamp with ON/OFF control, a zoom lens with a zoom control mechanism, a focusing lens with a focusing control mechanism, an audio system with a volume control, a projection-lamp light detector, a heat sensor, a variable-speed cooling fan, a control module having a microprocessor and a digital-to-analog converter, a display, a keypad, an alarm/annunciator, a power supply with ON/OFF control, and an infrared based remote control system able to control power ON/OFF, zoom, focus, picture, and sound volume.

Claims

1. A liquid crystal video projector (LCVP), comprising:

means for communicating a plurality of operating commands from locations both remote and local to the LCVP, the communication means having means to control a plurality of LCVP operating modes, said operating mode control means comprising a digital-to-analog converter;

means to detect when a projection lamp is operating;

power supply/ballast means to operate said projection lamp responsive to said operating mode control means and having means to attempt a limited number of projection lamp lighting restarts in response to the projection lamp detection means;

temperature sensing means for comparing the actual operating temperatures of the LCVP to a plurality of predetermined operating temperatures;

main power ON/OFF control means responsive to said operating mode control means;

a variable-speed fan for cooling of the LCVP, the fan speed responsive to the temperature sensing means such that a predetermined operating temperature is maintained;

alarm means to signal a user that at least one of said predetermined operating temperatures has been exceeded or that said projection lamp fails to operate, the alarm means responsive to the temperature sensing means and projection lamp restart means, the alarm means able to control the main power ON/OFF means and power supply/ballast means;

lens control means to control a system of lenses in response to said operating mode control means,the lens control means comprises means to zoom, means to focus, and means to move a projected image from a first position to a second position within a limited range on a projection screen, each means responsive to said operating mode control means;

means to select one of a plurality of signal sources to input to the LCVP, the selection means responsive to said operating mode control means;

means to adjust a plurality of picture attributes in response to said operating mode control means;

means to adjust sound volume in response to said operating mode control means;

means to memorialize and to restore said plurality of picture attributes and sound volume adjustments such that after power to the LCVP is turned off and back on, such adjustments as they existed before the power was turned off are restored after power is turned back on to their preexisting values; and

display means to indicate to a user a present status of each of said picture attributes and sound adjustments and to assist said user in the adjustment of said projected image on said projection screen, the display means comprising a plurality of indicator lights and an on-screen display system.

2. The projector of claim 1, wherein:

the means to memorialize and to restore comprises an erasable electrically-programmable read only memory (E² PROM);

said first position and said second position of said projected image are in vertical alignment with one another;

said means to move said projected image comprises means to automatically center said image in said limited range; and

said on-screen display system comprises timer means to hold an on-screen display image for a predetermined time.

3. A video projector, comprising:

means to project a video picture on to a screen, the projection means comprising imaging means having a liquid crystal device, a projection lamp with a power supply/ballast, and lens control means for adjusting the focus, size, and position of said video picture on said screen;

remote control means for adjusting a plurality of video picture attributes and at least one sound volume;

means to start said projection lamp and to restart said projection lamp a limited number of times if said projection lamp fails to start;

heat sensing and cooling means for maintaining an operating temperature of the video projector within predetermined bounds, the means able to signal an alarm and to shut-off a main power supply for the LCVP when said operating temperature exceeds said bounds;

input selection means for choosing among a plurality of signal sources to be input to the video projector, the selection means in communication with the video projection means;

command and indication means for accepting and processing user adjustments and inputs, the means comprising means to control said lens control means, said video picture, and said sound.

4. The projector of claim 3, wherein:

the heat sensing and cooling means comprises a variable-speed fan that runs at an increased speed after the video projector has been turned-off thereby shortening the time necessary to cool-down the video projector.

5. The projector of claim 3, wherein:

the remote control means comprises an infrared transmitter and receiver, said transmitter being hand-held and portable.

6. The projector of claim 3, wherein:

said video picture is projected in color; and

said remote control means comprises adjustments for stereo sound channels.

7. The projector of claim 3, wherein:

said projection lamp is a metal halide type lamp with an appropriate ballast; and

the means to start said projection lamp comprises means to signal an alarm and to shut-off a main power supply for the LCVP when said projection lamp fails to start after said limited number of times.

8. An improved liquid crystal video projection system having a projection lamp, a liquid crystal video panel device, a system of lenses, and a remote control system, the improvement comprising:

means to adjust the system of lenses such that a projected image can be moved from a first position to a second position within a limited range on a projection screen in response to a first and second command input to the remote control system and such that a third command input to the remote control system will cause said projected image to be automatically centered within said limited range.

9. The improvements in the system of claim 8, further comprising:

power supply means to attempt to start said projection lamp and to restart said projection lamp a limited number of times if said projection lamp fails to start.

10. The improvements in the system of claim 9, further comprising:

means to signal an alarm and to shut-off a main power supply for the system when said projection lamp fails to start after said limited number of times.

11. The improvements in the system of claim 8, further comprising:

an auto-focus means capable to being temporarily suspended from focusing during a transmission of an infrared beam of light by the remote control system.

12. A video projector, comprising:

imaging means comprising at least one liquid crystal display device;

a projection lamp positioned such that an image will be projected on a screen via the imaging means and a system of mirrors and lenses;

means for monitoring the operation of the projection lamp;

power supply means for controlling the operation of the projection lamp, the means responsive to the monitoring means;

means for displaying to a user a current condition of the projection lamp, the means responsive to the monitoring means; and

remote control means for adjusting said image on said screen by a user.

13. The projector of claim 12, wherein:

the monitoring means comprises a temperature sensor.

14. The projector of claim 12, wherein:

the monitoring means comprises a current sensor in series with the projection lamp.

15. The projector of claim 12, wherein:

the remote control means comprises an infrared transmitter and receiver.

16. The projector of claim 15, wherein:

said adjustment of said image comprises a picture zoom means, a picture focus means, a picture positioning means, a picture attribute adjustment means, and an auto-focus means having infrared ranging means.

17. The projector of claim 16, wherein:

said picture attribute adjustment means comprises adjustments for picture attributes of;

brightness, contrast color, hue, and sharpness.

18. The projector of claim 16, wherein:

said auto-focus means is temporarily suspended from focusing during a transmission of an infrared beam of light by the remote control means.

19. The projector of claim 12, wherein:

the power supply controlling means comprises means to cool the projection lamp at various levels and, alternatively, shut-off the projection lamp in response to the monitoring means.

20. The projector of claim 12, wherein:

the power supply controlling means comprises means to start and restart the projection lamp in response to the nonitoring means.

21. A video projector, comprising:

a microprocessor having a ROM memory and a RAM memory;

imaging means comprising at least one liquid crystal display device connected to television;

a projection lamp positioned such that a television image will be projected on a screen via the imaging means and via a system of lenses;

means for monitoring the operation of the projection lamp connected to the microprocessor;

power supply means for controlling the operation of the projection lamp, the means responsive to the monitoring means and connected to the microprocessor;

means for displaying whether or not the projection lamp is functional, the means responsive to the monitoring means and connected to the microprocessor; and

remote control means connected to the microprocessor for adjusting said image on said screen by a user.

22. The projector of claim 21, further comprising:

non-volatile random access memory means for saving said adjustments of said screen image during any periods that the projector is turned off.

23. A computer-implemented process in a liquid crystal video projector system having a microprocessor, a picture auto-focus means, and a infrared-based remote control means, comprising the steps of:

suspending said auto-focus means from focusing a picture during reception of a transmission of an imfrared light beam by said remote control means; and

resuming said auto-focusing of said picture after said transmission of said infrared light beam has ended.

24. A liquid crystal video projector having an illumination subsystem including a light source for providing an illuminating beam, a modulation subsystem provided to receive said beam to produce a modulatad output for projection of a formed image onto a surface, said illumination subsystem including auto light source checking means comprising:

a. means to detect the presence or absence of said beam,

b. means to turn on power to said light source,

c. means to delay the operation of said detection means for a first predetermined period of time after power is supplied to said light source so that said light source has sufficient time to become illuminated,

d. means to turn off said power supply if said detection means does not detect said beam after said predetermined period of time and initiate a second predetermined period of time, and thereafter re-initiate said power means and said delay means to turn on said light source,

e. counter means to keep track of the number of said reinitiations, and

f. means to terminate said re-initiations after said counter means reaches a predetermined count.

25. The liquid crystal video projector of claim 24 including means to visually indicate the status of said beam.

26. A computer-implemented process in a liquid crystal video projector (LCVP) system having a microprocessor with a RAM memory and an erasable electrically-programmable read only memory (E² PROM), comprising the steps of:

setting an audible user alarm;

turning-off a power supply for a projection lamp;

turning-off a main power supply for the LCVP system;

setting a visual user alarm;

setting a lamp failure flag in the RAM memory;

writing at least one flag in the RAM memory to the E² PROM;

waiting a predetermined time;

stopping a fan motor used to cool the LCVP system;

resetting said audible user alarm.

27. A liquid crystal video projector having an illumination subsystem including a light source for providing an illiminating beam, a modulation subsystem provided to receive said beam to produce a modulated output for projection of a formed image onto a surface, a fan means to cool said projector, and means to increase or decrease said fan speed, said projector comprising:

a. means to periodically detect the temperature of said projector;

b. means to increase said fan speed if said projector temperature is above a first predetermined temperature;

c. means to determine if said projector temperature has cooled below said first predetermined temperature and decrease said fan speed; and

d. means to turn off said light source and power to said projector if said projector temperature exceeds a second predetermined temperature, said second predetermined temperature being greater than said first predetermined temperature.

28. The liquid crystal video projector of claim 27 wherein said fan means is maintained at said increased fan speed after detection of said second predetermined temperature and turn-off of said light source and projector power until said projector temperature has cooled below said second predetermined temperature after which said fan means is turned off.

29. The liquid crystal video projector of claim 28 wherein visual display means indicates when said projector temperature exceeds said first predetermined temperature, when said projector temperture exceeds said second predetermined temperature after said light source and projector power have been turned off and said fan means continues in operation to cool said projector below said second predetermined temperature.