Patent US5793441A successfully refreshed from Google Patents.
US5793441A
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Method and apparatus for measuring illumination uniformity of a liquid crystal light valve projector
Assignee: JVCKenwood Corp
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Filing: 1995-09-25
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Granted: 1998-08-11
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Expires: 2015-09-25
Abstract
Abstract A system for measuring the illumination uniformity of a liquid light value (LCLV) for a LCLV projector includes a projection device including a first LCLV. The projection device reflects light from the first LCLV to form an image on a screen. An image sensing device senses illumination values for a plurality portions of said image. A processor is coupled to the image sensing device and the projection device. The processor determines an optimum voltage bias which provides a maximum illumination for the plurality of image pixels. The illumination uniformity measuring system can independently measure the illumination non-uniformity of the LCLV and illumination non-uniformity resulting from other sources such as projection lens roll-off, screen gain, and other illumination non-uniformities. Using the measured illumination non-uniformity, a correction system can improve the quality of the displayed image.
Inventors
- 👤 James G. Hagerman
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 13:48
CPC Classifications
H; H04; H04N; H04N5/00; H04N5/44; H04N5/57; H04N9/00; H04N9/12; H04N9/31; H04N9/3179; H04N9/3182; H04N9/3191; H04N9/3194
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
126 words
A method of measuring the illumination uniformity of a liquid crystal light valve (LCLV) of a projector, comprising the steps of: a) reflecting light from said LCLV to form an image on a screen; b) sensing an illumination value for each of a plurality of portions of said image using an image sensing device; c) comparing the sensed illumination value with a previously sensed illumination value for said each of a plurality of portions of said image to determine if an optimum illumination value has been reached; and d) adjusting an LCLV driver, based on the step of comparing the sensed illumination value with a previously sensed illumination value, until an optimum illumination value is reached for each of said plurality of portions of said image.
Claim 2
Independent Claim
126 words
A method of measuring the illumination uniformity of a liquid crystal light valve (LCLV) of a projector, comprising the steps of: a) reflecting light from said LCLV to form an image on a screen; b) sensing an illumination value for each of a plurality of portions of said image using an image sensing device; c) comparing the sensed illumination value with a previously sensed illumination value for said each of a plurality of portions of said image to determine if an optimum illumination value has been reached; and d) adjusting an LCLV driver, based on the step of comparing the sensed illumination value with a previously sensed illumination value, until an optimum illumination value is reached for each of said plurality of portions of said image.
Claim 3
Dependent Claim
29 words
The method of claim 1 further comprising the step of: e) repeating steps a) through d) for a plurality of LCLVs each associated with a distinct color of light.
Claim 4
Dependent Claim
64 words
The method of claim 1 wherein step d) comprises the steps of: incrementing an LCLV driver voltage bias value; measuring a new illumination value for said incremented LCLV driver voltage bias level; comparing said new illumination value to said old illumination value; and setting said old illumination value equal to said new illumination value if said new illumination value exceeds said old illumination value.
Claim 5
Dependent Claim
24 words
The method of claim 3 wherein step d) further comprises repeating the steps recited in claim 4 for each remaining portion of said image.
Claim 6
Independent Claim
111 words
A system for measuring the illumination uniformity of a liquid crystal light valve (LCLV) for a LCLV projector, comprising: projection means, including a first LCLV, for reflecting light from said first LCLV to form an image on a screen, said projection means further including an LCLV driver that drives said LCLV; image sensing means for sensing an illumination value, controlled by said LCLV driver, for a plurality of portions of said image; and processing means, coupled to said image sensing means and said projection means, for determining when said image sensing means senses an optimum LCLV driver level which provides a maximum illumination for said plurality of portions of said image.
Claim 7
Independent Claim
111 words
A system for measuring the illumination uniformity of a liquid crystal light valve (LCLV) for a LCLV projector, comprising: projection means, including a first LCLV, for reflecting light from said first LCLV to form an image on a screen, said projection means further including an LCLV driver that drives said LCLV; image sensing means for sensing an illumination value, controlled by said LCLV driver, for a plurality of portions of said image; and processing means, coupled to said image sensing means and said projection means, for determining when said image sensing means senses an optimum LCLV driver level which provides a maximum illumination for said plurality of portions of said image.
Claim 8
Dependent Claim
26 words
The system of claim 5 further comprising: pointing means, associated with said processing means, for sequentially selecting each of said plurality of portions of said image.
Claim 9
Dependent Claim
21 words
The system of claim 5 wherein said projector includes a plurality of LCLVs each associated with a distinct color of light.
Claim 10
Dependent Claim
24 words
The system of claim 7 further comprising: LCLV pointing means, associated with said processing means, for sequentially identifying each of said plurality of LCLVs.
Claim 11
Dependent Claim
38 words
The system of claim 5 further comprising: voltage setting means for successively incrementing a voltage bias level on said first LCLV, wherein said image sensing means measures a new illumination value corresponding to said incremented voltage bias level.
Claim 12
Dependent Claim
25 words
The system of claim 9 wherein said processing means includes optimum locating means for identifying, for each portion of said image, a maximum illumination value.
Claim 13
Dependent Claim
20 words
The system of claim 5 wherein said image sensing means includes a charge coupled device camera directed at said screen.
Claim 14
Independent Claim
147 words
A system for measuring the illumination uniformity of a liquid crystal light valve (LCLV) for a LCLV projector comprising: projection means, including a first LCLV, for projecting light which is modulated by said first LCLV to produce an image on a screen, the light having an illumination value corresponding to a projection means voltage bias level; image sensing means for sensing an illumination value for a plurality of portions of said image; and at least one processor, coupled to said image sensing means and said projection means, that identifies a maximum illumination value sensed by said image sensing means for at least one of said plurality of portions of said image through successive comparison, via a negative feedback loop, of a present illumination value with a previously measured illumination value as said voltage vias level is increased in predetermined increments up to an optimum voltage bias level.
Claim 15
Independent Claim
147 words
A system for measuring the illumination uniformity of a liquid crystal light valve (LCLV) for a LCLV projector comprising: projection means, including a first LCLV, for projecting light which is modulated by said first LCLV to produce an image on a screen, the light having an illumination value corresponding to a projection means voltage bias level; image sensing means for sensing an illumination value for a plurality of portions of said image; and at least one processor, coupled to said image sensing means and said projection means, that identifies a maximum illumination value sensed by said image sensing means for at least one of said plurality of portions of said image through successive comparison, via a negative feedback loop, of a present illumination value with a previously measured illumination value as said voltage vias level is increased in predetermined increments up to an optimum voltage bias level.
Claim 16
Dependent Claim
32 words
The system of claim 12 further comprising: pointing means, associated with said control means and said at least one processor, for sequentially selecting each of said plurality of portions of said image.
Claim 17
Dependent Claim
21 words
The system of claim 12 wherein said projector includes a plurality of LCLVs each associated with a distinct color of light.
Claim 18
Dependent Claim
30 words
The system of claim 14 further comprising: LCLV pointing means, associated with said control means and said at least one processor, for sequentially selecting each of said plurality of LCLVs.
Claim 19
Dependent Claim
42 words
The system of claim 12 further comprising: voltage setting means, associated with said control means and said processor, for successively incrementing the projection means voltage bias level, wherein said image sensing means measures an illumination value corresponding to said voltage bias level.
Claim 20
Dependent Claim
32 words
The method of claim 1, further comprising the step of storing the optimum LCLV driver level for each of said plurality of portions of said image for overall LCLV level adjustment purposes.
Claim 21
Dependent Claim
16 words
The system of claim 5, wherein the LCLV driver level comprises an LCLV voltage bias level.
Claim 22
Dependent Claim
97 words
The method of claim 1, wherein said step of adjusting the LCLV driver comprises the steps of: successively comparing a present illumination value with a previous illumination value as said driver level is increased in predetermined increments up to an optimum driver level; and ending the successive comparisons of the present illumination values and the previous illumination values, and storing the previous illumination value for each of the plurality of portions of said image, when the sensed present illumination value is less than the previous illumination value, thereby indicating that the optimum illumination value has been achieved.
Claim 23
Independent Claim
176 words
A system for measuring the illumination uniformity of a liquid crystal light valve (LCLV) for a LCLV projector comprising: a projector, including an LCLV, that projects, at a predetermined level, light which is modulated by said LCLV to produce an image on a screen; an image sensor that senses an illumination value for a plurality of portions of said image; and at least one processor, coupled to said image sensor and said projector, that identifies a maximum illumination value sensed by said image sensor for at least one of said plurality of portions of said image through successive comparison of a present illumination value with a previous illumination value as said projector level is increased in predetermined increments up to an optimum projector level, said processor ending the successive comparisons of the present illumination values and the previous illumination values, and storing the previous illumination value for each of the plurality of portions, when the sensed present illumination value is less than the previous illumination value, thereby indicating that the optimum illumination value has been achieved.
Claim 24
Independent Claim
176 words
A system for measuring the illumination uniformity of a liquid crystal light valve (LCLV) for a LCLV projector comprising: a projector, including an LCLV, that projects, at a predetermined level, light which is modulated by said LCLV to produce an image on a screen; an image sensor that senses an illumination value for a plurality of portions of said image; and at least one processor, coupled to said image sensor and said projector, that identifies a maximum illumination value sensed by said image sensor for at least one of said plurality of portions of said image through successive comparison of a present illumination value with a previous illumination value as said projector level is increased in predetermined increments up to an optimum projector level, said processor ending the successive comparisons of the present illumination values and the previous illumination values, and storing the previous illumination value for each of the plurality of portions, when the sensed present illumination value is less than the previous illumination value, thereby indicating that the optimum illumination value has been achieved.
Claim 25
Dependent Claim
22 words
The system of claim 20, wherein said projector includes an LCLV driver that drives said LCLV at an LCLV voltage bias level.
Claim 26
Dependent Claim
34 words
The system of claim 21, wherein said processor increases the LCLV voltage bias level to increase the sensed illumination value during the successive comparison of a present illumination value with a previous illumination value.
Claim 27
Dependent Claim
35 words
The system of claim 20, wherein the processor senses and stores optimum driver level data for each image portion, and subsequently utilizes the stored data to determine an optimum overall driver level for the LCLV.
Claim 28
Dependent Claim
42 words
The system of claim 23, wherein the processor senses and stores optimum driver level data for each image portion of a plurality of LCLVs, and subsequently utilizes the stored data to determine an optimum overall driver level for each of the LCLVs.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2001-08-10 | 2002-02-09 | 2002-08-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2005-08-10 | 2006-02-09 | 2006-08-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2009-08-10 | 2010-02-09 | 2010-08-11 | $7700.00 | Window Closed / Lapsed |