Prior art

As a senior technical patent analyst, I have identified and analyzed the prior art references cited during the prosecution of US patent 9,900,569. The analysis focuses on the potential for these references to anticipate the independent claim (Claim 1) under 35 U.S.C. § 102.

Claim 1 of US patent 9,900,569 describes a projector that compensates for age-related lamp dimming by using a control unit that adjusts the image signal based on two specific inputs: the detected lamp voltage and the accumulated lamp usage period. The novelty of the claim rests on the combination of these specific inputs to control the image correction process, thereby avoiding the need for a separate optical sensor to measure brightness directly.

Below are the most relevant prior art references considered by the USPTO examiner and an analysis of their relevance to Claim 1.

Analysis of Cited Prior Art

The following references were cited by the examiner during the patent's prosecution.

1. Japanese Patent Application Laid-Open No. 2004-39563 (JP2004-39563A)

• Full Citation: JP2004-39563A, "Discharge Lamp Lighting Device And Projector," published February 12, 2004.
• Description: This reference, identified as "Patent Literature 1" in the '569 patent text, discloses a system that detects lamp voltage to identify an arc failure in a discharge lamp. The purpose of this detection is to control the lamp drive circuit to stabilize the discharge, restrain image flicker, and improve light distribution uniformity.
• Anticipation Analysis (Claim 1): This reference does not anticipate Claim 1. While it teaches the detection of a lamp voltage (an element of Claim 1), its stated purpose is to manage immediate operational issues like arc failure, not to compensate for long-term, gradual deterioration in illumination. The '569 patent explicitly distinguishes itself by stating this prior art "does not cope with a deterioration over time in intensity of illumination due to an accumulated usage period" (Description, col. 1, lines 42-45). It fails to teach using lamp voltage in combination with the lamp usage period to control an image correction processing unit.

2. Japanese Patent Application Laid-Open No. 2010-210742 (JP2010-210742A)

• Full Citation: JP2010-210742A, "Projector And Method For Adjusting Projected State Of Image," published September 24, 2010.
• Description: This reference, identified as "Patent Literature 2," describes a projector that uses a dedicated optical sensor to directly detect the deterioration of the lamp's illuminating light. Based on the sensor's readings, the system can issue a lamp exchange warning or perform image processing for color correction if the color balance degrades.
• Anticipation Analysis (Claim 1): This reference does not anticipate Claim 1. The core inventive concept of the '569 patent is the use of lamp voltage as an indirect indicator of lamp health, specifically to avoid the cost and potential mounting errors associated with a separate optical sensor. As the '569 patent notes, "The configuration that detects the deterioration in illuminating light of the lamp by the optical sensor causes the following problems. Since the optical sensor is newly disposed, a cost increases" (Description, col. 2, lines 6-9). Because JP2010-210742A teaches using an optical sensor and not a lamp voltage detection unit for this purpose, it does not teach a key element of Claim 1.

3. United States Patent 7,538,503 B2 (US7538503B2)

• Full Citation: US 7,538,503 B2, "Lamp driving device and projector," assigned to Seiko Epson Corp., issued May 26, 2009 (filed Apr 4, 2006).
• Description: This patent describes a lamp driving device that monitors lamp parameters, including lamp voltage and cumulative lighting time. It uses this information primarily to adjust the lamp power to maintain a constant level of brightness as the lamp ages, or to prevent the lamp from operating under damaging conditions.
• Anticipation Analysis (Claim 1): This reference does not anticipate Claim 1. Although it teaches monitoring both lamp voltage and usage time, its control mechanism is different. US 7,538,503 B2 adjusts the power supplied to the lamp to counteract dimming. In contrast, the '569 patent adjusts the image signal sent to the display element (e.g., brightness, contrast, gamma) while the lamp power is controlled separately to remain constant. Therefore, US 7,538,503 B2 does not teach controlling an "image correction processing unit" in the manner claimed.

4. United States Patent 8,638,393 B2 (US8638393B2)

• Full Citation: US 8,638,393 B2, "Projector and method of controlling the same," assigned to Seiko Epson Corp., issued January 28, 2014 (filed Dec 27, 2010).
• Description: This patent discloses a projector that aims to maintain image quality over time. It measures the accumulated lighting time of the light source and, based on this duration, selects a corresponding set of image adjustment parameters (e.g., for gradation, color balance) from a stored table to correct the image data.
• Anticipation Analysis (Claim 1): This reference does not anticipate Claim 1. It teaches using the lamp usage period to control image correction, which covers some elements of Claim 1. However, it fails to teach the use of the detected lamp voltage as a second input for the control unit. The '569 patent's invention relies on the combination of both usage time and real-time lamp voltage to create a more accurate and individualized correction profile, accounting for variations between individual lamps. Because US 8,638,393 B2 omits the lamp voltage input for this purpose, it does not disclose all elements of the claim.