Image display apparatus, multidisplay apparatus, and brightness management apparatus

• US 7,589,695 B2
• Filed: 05/21/2003
• Issued: 09/15/2009
• Est. Priority Date: 05/21/2002
• Status: Active Grant

• Current Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Original Assignee: Panasonic Corporation (Panasonic Holdings Corporation)
• Inventors: Tanaka, Teruto
• Primary Examiner(s): Eisen; Alexander
• Assistant Examiner(s): Mandeville; Jason M
• Application Number:
  US10/514,088
• Publication Number:
  US 20050219271A1
• Time in Patent Office: 2,309 Days
• Field of Search: 345 11- 13, 345 21- 23, 345 4- 9, 345 31- 33, 345/40, 345/77, 345/205, 345/211, 345/214, 345/690
• US Class Current: 345/1.3
• CPC Class Codes: G03B 21/13 Projectors for producing special effects at the edges of picture, e.g. blurring
• CPC Class Codes: G03B 21/14 Details
• CPC Class Codes: G03B 21/2053 Intensity control of illuminating light controlled by video signal processing H04N5/74 or H04N9/31
• CPC Class Codes: G03B 37/04 with cameras or projectors providing touching or overlapping fields of view
• CPC Class Codes: H04N 9/12 Picture reproducers H04N9/11 takes precedence
• CPC Class Codes: H04N 9/3147 Multi-projection systems displays in general H04N9/12; video walls G06F3/1446, G09G2300/026

Abstract

A multi-display device for connecting projection screens of a plurality of image display devices so as to form one-screen image. Each of the image display devices includes a luminance lowering characteristic storage unit for storing a look-up table indicating average luminance lowering characteristic of a projection lamp, a timer unit for counting the lit time of lamp of the device, a lit time storage unit for accumulating and storing the lit time from the lamp use start moment, and an external communication unit for communicating.

Claims

1. An image display apparatus of projection-type used in a multidisplay apparatus in which a plurality of image display apparatuses are arranged so as to realize respective projection pictures adjacent to each other, each of the image display apparatus comprising:

an image forming device configured to form an image according to an image signal;

a projection unit including a projection lamp, and configured to form a projection picture by projecting the formed image onto a projection screen;

a first memory unit configured to store lighting hours accumulated since an operating start of the projection lamp of the projection unit;

a second memory unit configured to store an average relation between brightness decrease and accumulated lighting hours for a projection lamp, as a brightness characteristic;

a brightness estimate unit configured to estimate brightness of the projection lamp based on the lighting hours stored in the first memory unit and the brightness characteristic stored in the second memory unit;

a communication unit configured to communicate with other image display apparatuses in the multidisplay apparatus;

a brightness information obtaining unit configured to obtain information that indicates, based on lighting hours of projection lamps of the other image display apparatuses, brightness of the projection lamps of the other image display apparatuses, via the communication unit;

a specifying unit configured to specify an image display apparatus whose projection lamp has lowest brightness among the image display apparatuses, based on the estimated brightness and the information obtained by the brightness information;

a brightness correction unit configured to correct brightness of the projection picture formed by the projection unit so as to be in agreement with brightness of a projection picture formed by the image display apparatus specified by the specifying unit;

a brightness adjustment reception unit configured to receive brightness adjustment for the projection unit input by a user;

a lamp change detection unit including a photoelectronic sensor, the photoelectronic sensor outputting a signal representative of a strength of a light flux of the projection lamp which is regularly sampled, and when a current sample of the signal representative of the strength of the light flux shows a great increase from the latest sample of the signal representative of the strength of the light flux, the lamp change detection unit detects that the projection lamp has been replaced with another projection lamp, wherein upon detection by the lamp change detection unit, that the projection lamp has been replaced with the another projection lamp, then the first memory unit resets the lighting hours stored therein; and

a correction coefficient obtaining unit configured to obtain a correction coefficient for correcting the estimated brightness, in accordance with the brightness adjustment received from the user,

wherein the correction coefficient is Ya/Yb, where Ya is a brightness before the adjustment by the user, and Yb is a brightness after the adjustment by the user and the brightness estimate unit corrects the estimated brightness of the projection lamp based on the correction coefficient and the estimated brightness of the projection lamp based on the lighting hours.

2. The image display apparatus of claim 1, wherein

the brightness correction unit does not correct the brightness of the projection picture formed by the projection unit, when the brightness of the projection lamp of the projection unit is the lowest, and

the brightness correction unit corrects the brightness of the projection picture formed by the projection unit, when projection-lamp brightness of any of the other image display apparatuses in the multidisplay apparatus is the lowest, so that the projection picture formed by the projection unit outputs the same brightness as brightness of a projection picture of the lowest brightness apparatus.

3. The image display apparatus of claim 1, wherein

the brightness correction unit corrects the brightness of the projection picture formed by the projection unit, by referring to a gamma characteristic showing a relation between a signal value of an inputted image voltage and brightness of a projection picture outputted according to the inputted image signal, to obtain an amount of signal value to be changed so as to achieve target brightness, and by controlling the signal value of the image signal according to the obtained amount of signal value to be changed.

6. The image display apparatus of claim 1, wherein

the brightness estimate unit obtains an approximate expression that reflects the brightness characteristic of the projection lamp that has been actually attached to the projection unit based on two brightness adjustments received by the brightness adjustment reception unit after a prescribed time has passed from the operating start, and corrects the brightness characteristic based on the approximate expression.

7. The image display apparatus of claim 1, wherein

the information indicating brightness of the projection lamps of the other image display apparatuses, received via the communication unit, includes lighting hours of the other image display apparatuses accumulated since an operating start of the other image display apparatuses, and the correction coefficient obtained by the correction coefficient obtaining unit, and

the specifying unit estimates brightness of the projection lamps of the other image display apparatuses based on the brightness characteristic, the accumulated lighting hours of the other image display apparatuses and the correction coefficient, and specifies the image display apparatus whose projection lamp has lowest brightness among the image display apparatuses based on the estimated brightness of the projection lamp of the projection unit and the information indicating brightness of the projection lamps of the other image display apparatuses.

8. The image display apparatus of claim 1, wherein

the information indicating brightness of the projection lamps of the other image display apparatuses, received via the communication unit, indicates brightness estimated by the brightness estimate unit of each of the other image display apparatuses, and

the specifying unit specifies the image display apparatus whose projection lamp has lowest brightness among the image display apparatuses by comparing the brightness of the projection lamps of the other image display apparatuses with each other.

4. A multidisplay apparatus comprising:

a plurality of projection image display apparatuses arranged so as to realize respective projection pictures adjacent to each other; and

an image distribution unit configured to generate image signals respectively used for display realized at the image display apparatuses, from an inputted image signal, and to distribute the generated image signals to the image display apparatuses respectively, wherein

each of the image display apparatuses includes;

an image forming device configured to form an image according to an image signal;

a projection unit including a projection lamp, and configured to form a projection picture by projecting the formed image onto a projection screen;

a first memory unit configured to store lighting hours accumulated since an operating start of the projection lamp of the projection unit;

a second memory unit configured to store an average relation between brightness decrease and accumulated lighting hours for a projection lamp, as brightness characteristic;

a brightness estimate unit configured to estimate brightness of the projection lamp based on the lighting hours stored in the first memory unit and the brightness characteristic stored in the second memory unit;

a communication unit configured to communicate with other image display apparatuses in the multidisplay apparatus;

a brightness information obtaining unit configured to obtain information that indicates, based on lighting hours of projection lamps of the other image display apparatuses, brightness of the projection lamps of the other image display apparatuses, via the communication unit;

a specifying unit configured to specify an image display apparatus whose projection lamp has lowest brightness among the image display apparatuses, based on the estimated brightness and the information obtained by the brightness information;

a brightness correction unit configured to correct brightness of the projection picture formed by the projection unit so as to be in agreement with brightness of a projection picture of the image display apparatus specified by the specifying unit;

a brightness adjustment reception unit configured to receive brightness adjustment for the projection unit input by a user;

a lamp change detection unit including a photoelectronic sensor, the photoelectronic sensor outputting a signal representative of a strength of a light flux of the projection lamp which is regularly sampled, and when a current sample of the signal representative of the strength of the light flux shows a great increase from the latest sample of the signal representative of the strength of the light flux, the lamp change detection unit detects that the projection lamp has been replaced with another projection lamp, wherein upon detection by the lamp change detection unit, that the projection lamp has been replaced with the another projection lamp, then the first memory unit resets the lighting hours stored therein; and

a correction coefficient obtaining unit configured to obtain a correction coefficient for correcting the estimated brightness, in accordance with the brightness adjustment received from the user,

wherein the correction coefficient is Ya/Yb, where Ya is a brightness before the adjustment by the user, and Yb is a brightness after the adjustment by the user and further wherein the brightness estimate unit corrects the estimated brightness of the projection lamp based on the correction coefficient and the estimated brightness of the projection lamp based on the lighting hours.

5. A multidisplay apparatus comprising:

a plurality of projection image display apparatuses arranged so as to realize respective projection pictures adjacent to each other; and

an image distribution unit configured to generate image signals respectively used for display realized at the image display apparatuses, from an inputted image signal, and to distribute the generated image signals to the image display apparatuses respectively, wherein

the image distribution unit includes;

a first memory unit configured to store lighting hours accumulated since an operating start of the projection lamp of each display apparatus;

a second memory unit configured to store an average relation between brightness decrease and accumulated lighting hours for a projection lamp, as brightness characteristic;

a brightness estimate unit configured to estimate brightness of the projection lamp of each display apparatus based on the lighting hours stored in the first memory unit and the brightness characteristic stored in the second memory unit;

a specifying unit configured to specify an image display apparatus whose projection lamp has lowest brightness among the image display apparatuses by comparing brightness of projection lams of the display apparatuses with each other;

a brightness correction unit configured to correct brightness of projection pictures formed by the display apparatuses so as to be in agreement with brightness of a projection picture formed by the image display apparatus specified by the specifying unit;

a brightness adjustment reception unit configured to receive brightness adjustment for a certain display apparatus input by a user;

a lamp change detection unit including a photoelectronic sensor, the photoelectronic sensor outputting a signal representative of a strength of a light flux of one of the projection lamps of the plurality of projection image display apparatuses which is regularly sampled, and when a current sample of the signal representative of the strength of the light flux shows a great increase from the latest sample of the signal representative of the strength of the light flux, the lamp change detection unit detects that the one projection lamp of the plurality of projection image display apparatuses has been replaced with another projection lamp, wherein upon detection by the lamp change detection unit, that the one projection lamp of the plurality of projection image display apparatuses has been replaced with the another projection lamp, then the first memory unit resets the lighting hours stored therein for the one projection lamp of the plurality of projection image display apparatuses; and

a correction coefficient obtaining unit configured to obtain a correction coefficient for correcting the estimated brightness, in accordance with the brightness adjustment received from the user,

wherein the correction coefficient is Ya/Yb, where Ya is a brightness before the adjustment by the user, and Yb is a brightness after the adjustment by the user and further wherein the brightness estimate unit corrects the estimated brightness of the projection lamp based on the correction coefficient and the estimated brightness of the projection lamp based on the lighting hours.