Projection type image display apparatus

• US 9,010,944 B2
• Filed: 03/17/2009
• Issued: 04/21/2015
• Est. Priority Date: 03/18/2008
• Status: Active Grant

• Current Assignee: Konica Minolta Inc.
• Original Assignee: Konica Minolta OPTO Incorporated (Konica Minolta Inc.)
• Inventors: Wataru, Kohei, Inoue, Kazuhiko, Terada, Masahiro, Sawai, Yasumasa, Maeda, Norio, Ohta, Takashi
• Primary Examiner(s): Dowling, William C
• Assistant Examiner(s): BROOKS, JERRY L.
• Application Number:
  US12/922,657
• Publication Number:
  US 20110019109A1
• Time in Patent Office: 2,226 Days
• Field of Search: 353/101, 353/69
• US Class Current: 353/101
• CPC Class Codes: G03B 21/00 Projectors or projection-type viewers; Accessories therefor devices for changing pictures G03B23/00
• CPC Class Codes: G03B 21/005 Projectors using an electronic spatial light modulator but not peculiar thereto
• CPC Class Codes: G03B 21/53 Means for automatic focusing, e.g. to compensate thermal effects
• CPC Class Codes: H04N 9/317 Convergence or focusing systems electronic adjustment of convergence H04N9/3185; convergence or focusing arrangements for cathode ray tubes H04N9/28; means for automatic focusing of projectors not peculiar to the presence of an electronic spatial light modulator G03B21/53

Abstract

A projection type image display apparatus (1) comprises a focus correction system (30). The system includes a temperature detection mechanism (16) for measuring temperature in the vicinity of a projection lens group (13), a correction amount calculation unit (18) for calculating a correction amount for correcting the focus shift caused by a temperature change, and a driving signal generation unit (19) for generating, based on the correction amount, a driving signal for driving a focus adjustment mechanism (15). If the user performs a focus adjustment using a focus operation input unit (23), a focus operation determination unit (21) determines that a focus adjustment has occurred independently of the focus correction system and changes a correction condition stored in a memory (20).

Claims

1. A projection type image display apparatus comprising:

a projection optical system having a focus lens whose position is movable along an optical axis;

a temperature sensor configured to measure a temperature of the projection optical system;

a memory configured to store therein correction information in a correction table, for correcting a position of the focus lens in accordance with the measured temperature;

a focus lens control portion configured to perform control for correcting the position of the focus lens to be placed, based on the measured temperature and the correction information, the correction information stored in advance in the correction table in the memory, before control is performed by the focus lens control portion;

an input portion through which a user manually adjusts the position of the focus lens, wherein control for correcting the position of the focus lens is performed prior to a manual adjustment of the focus lens by the user;

a determination portion that determines if there is an operation of the input portion by the user; and

a correction portion configured to correct and rewrite at least a portion of the correction information in the correction table in the memory, based on an amount of movement of the focus lens caused by the input portion if the determination portion determines that there is an operation of the input portion after the focus lens control portion starts to perform control for correcting the position of the focus lens, and to store the corrected correction information in the correction table as rewritten correction information in the memory.

2. The projection type image display apparatus according to claim 1, wherein

if the determination portion determines that there is an operation of the input portion after the focus lens control portion starts to perform control for correcting the position of the focus lens, a temperature and a position of the focus lens immediately after the focus lens is moved by the input portion are stored in the memory;

and

the correction portion, immediately before turning-off a power supply of the apparatus, further corrects the correction information based on the measured temperature and the position of the focus lens that are stored in the memory.

3. The projection type image display apparatus according to claim 1, wherein the correction information comprises:

a predetermined function table, and

wherein the correction portion corrects the predetermined function table based on the amount of movement of the focus lens moved by use of the input portion.

4. The projection type image display apparatus according to claim 3, wherein

the correction portion corrects the predetermined function table using the following formula: