JP2006146048A - Projection type projector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection type projector equipped with a DVI-I or HDMI interface having a lamp light source and a hot plug detection function. <P>SOLUTION: In a display device including the DVI-I or HDMI interface having the hot plug detection function, a hot plug detection signal can be controlled by a control means, such as a microcomputer, and the display device has a function of previously keeping a hot plug detection signal for a previously specified time turned off after the startup of a power source, and turning on the hot plug detection signal when the previously specified time elapses. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a projection type projector having a DVI-I or HDMI interface having a lamp light source and a hot plug detect function.

  The DVI (Digital Visual Interface) is a digital interface for which the standard of the DDWG (Digital Display Working Group) has been established. The digital data transfer system consists of 3 channel image data transmission lines (red, green, blue) and 1 channel clock transmission line, a total of 4 channels, and the serial signal of each transmission line is single-ended differential TMDS (Transition Minimized Differential Signaling), which is a signal transmission method, is employed.

  The hot plug detect function is a function for realizing an automatic environment setting function, a so-called plug and play method, on a computer system. When a display device such as a projector is connected to a computer, the computer obtains information (hereinafter referred to as EDID) related to the display device necessary for plug and play from the display device by DDC communication with the display device, and the display device is based on the EDID. The image output corresponding to is performed.

  Conventionally, an analog interface represented by the D-Sub connector specification has been used as the interface of the display device. When a display device is connected to a computer having an output of the D-Sub specification via an analog interface, there is a concern about deterioration in display quality due to analog / digital conversion of a video signal and an increase in the cost of the device. With the spread of flat displays such as liquid crystal displays (LCDs), the expectation for standardization of digital interfaces is increasing based on the fact that many digital projectors have become common.

  FIG. 2 is a diagram showing a connector of DVI specification. By driving the hot plug detect pin on the display device side, it is possible to determine whether or not the display device is in a connected state on the image output device side such as a computer.

When the 16th pin (hot plug detect) of the DVI connector is driven to a high state (+2.4 V or higher) on the display device side, the image output device side such as a computer detects that the display device is in a connected state. Further, when the Low state (+0.4 V or less) is set, it is determined that the display device is not connected. When it is detected that the display device is in a connected state, an image output device such as a PC outputs a display image, but a normal display device represented by a display such as an LCD or CRT is connected if the power is on. Needless to say, the state is a displayable state.
JP 2001-109577 A

  However, in a display device such as an LCD display or a plasma display (hereinafter referred to as PDP) that takes time from start to display, or a display device having a lamp light source such as a projector, the brightness of the lamp is weak immediately after the power is turned on. It is very difficult to confirm.

  As shown in FIG. 3, a light source such as a lamp gradually increases in brightness after activation and reaches a brightness at which an image can be recognized only after a certain time has elapsed. In the meantime, the image output device naturally assumes the display device connection state and performs the image output operation. An image output device such as a computer displays important information such as initial settings at startup. However, since the brightness of the lamp light source is not sufficient, the user may not be able to check these initial screens. Even if the lamp is not activated, if the computer is connected, the computer operates assuming that the display device can display.

  SUMMARY An advantage of some aspects of the invention is that it provides a projection projector including a lamp light source and a DVI-I or HDMI interface having a hot plug detect function.

  In order to achieve the above object, an image display apparatus according to the present invention is a display apparatus having a DVI-I or HDMI interface having a hot plug detect function, and a hot plug detect signal is obtained by a control means such as a microcomputer. It has a function of turning off the hot plug detect signal for a predetermined time after the power is turned on and turning on the hot plug detect signal after the predetermined time has elapsed. .

  Further, the image display device is a projector having a lamp light source and a DVI-I or HDMI interface having a hot plug detect function, and can control a hot plug detect signal by a control means such as a microcomputer when the power is turned on. A function of generating a lamp ON signal, turning off the hot plug detect signal for a predetermined time, and turning on the hot plug detect signal when the predetermined time has elapsed.

  According to the present invention, it is possible to provide a projection type projector that can confirm important information output from a computer even if the brightness is insufficient immediately after the power is turned on.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a schematic configuration that is the basis of a liquid crystal projector as an example of a display device corresponding to the present invention.

  In the projector apparatus shown in FIG. 1, reference numeral 102 denotes an input unit including a DVI-I, HDMI, DVI-D, or HDMI interface connector (not shown), and a composite color is input from the input unit 102 to the DVI decoder 10 or the A / D converter 11. A video signal is supplied. The supplied composite color video signal is sent to the resolution conversion unit 14, performs resolution conversion processing, gamma correction, scaling processing, and the like, and is sent to the color correction processing unit 15. The color correction processing unit 15 performs VT (transmittance-voltage) correction corresponding to the structure of the optical system and the structure of the liquid crystal panel, and the video signal is sent to a liquid crystal display (LCD) drive unit 16. The LCD driving circuit 16 drives to display the three liquid crystal display panels 17R, 17G, and 17B corresponding to the respective colors. In these liquid crystal display panels 17R, 17G, and 17B, images of the respective colors R, G, and B obtained by transmitting light from a light source such as the lamp 101 are projected onto the screen surface via the projection lens 100.

  The input unit 12 is a command data input interface unit including RS-232, USB, and the like, includes an interface driver (not shown), and is connected to the CPU 18. The EEPROM 20 is a rewritable nonvolatile memory and has a function of storing a specified measurement time, other operation initial values, and the like.

  In FIG. 4, differential data is transmitted to the DVI-I or HDMI interface 41 from an image output device such as a computer (not shown) via the TMDS transmission line. In the DVI decoder 10, a 3-channel image data transmission path (red, green, blue) and a 1-channel clock are restored to digital data and transmitted to the resolution converter, and the color corrector 15 and the liquid crystal shown in FIG. An image is displayed on the liquid crystal unit 17 via the drive unit 16. The 16-pin hot plug detect signal pin of the DVI-I or HDMI interface 41 can be controlled by the CPU 18 and further has a function of transmitting a lamp ON signal to the lamp ballast 13 for driving the lamp light source. The CPU 18 has a time measurement function (not shown), measures a predetermined time T1 after generating the lamp ON signal, and turns on the hot plug detect signal after the time T1 has elapsed. The specified time T1 is set so that the setting of the specified time T1 stored in the EEPROM 20 can be changed via the input unit 12 or the operation panel 19, and the time for the projected image to reach a brightness that can be recognized by the user after the lamp is turned on is set. Alternatively, the computer image may be adjusted so that it can be appropriately displayed when the display can be recognized.

  Next, the operation of the present invention will be described with reference to a flowchart shown in FIG.

  In S1, the power is turned on, and the user presses the power button on the operation panel or a remote control (not shown) to activate the image display device. In S2, the apparatus system is activated, the measurement time is cleared, each initial value is set, and the hot plug detect signal is turned off. In S <b> 3, the CPU 18 transmits a lamp ON signal to the lamp ballast 13. In S4, a prescribed measurement time T1 stored in the EEPROM 20 is set. Time measurement started in S5. Whether or not T1 time has elapsed is monitored in S6, and if T1 time has not elapsed, the process returns to S6, and if it has elapsed, the process proceeds to S7. In S7, the hot plug detect signal is turned ON. Signal input start and image display start in S8. In S9, the lamp is turned off and the hot plug detect signal is turned off at the same time as the power is turned off. The operation ends in S10.

  Note that the present invention is not limited to a projector and is not in the embodiment, but other display devices such as PDPs, LCDs, and the like that take a long time from being turned on to being able to display can be generally supported. .

It is a block diagram which shows schematic structure of an image display apparatus. Diagram showing DVI specification connector Image diagram showing the operating status of conventional image display devices 1 is a block diagram showing a schematic configuration of an image display device according to the present invention. The flowchart which shows operation | movement of the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Liquid crystal projector 100 Projection lens 101 Lamp 102 Input part 103 I2C bus 10 Video decoder 11 A / D converter 12 Input part 13 Lamp ballast 14 Resolution conversion part 15 Color correction process part 16 Liquid crystal drive part 17 Liquid crystal display part 18 CPU
19 Operation panel 20 EEPROM
41 DVI-I or HDMI interface

Claims (4)

A light source;
Switching means for turning on and off the light source;
An image input connection terminal;
Display means for displaying an image input from an image input connection terminal using the light source;
Detecting means for detecting that an external device is connected to the image input means,
An image display device, wherein the detection means prohibits detection for a predetermined time after the light source is switched on.   The image display device according to claim 1, wherein a predetermined time from when the switching unit is switched to when the detection unit is released can be adjusted.   An image display device comprising: an image input interface having a connection detection function; and a light source for image projection or image display, and a function of enabling a connection detection signal after a predetermined time from the start of lighting of the light source. The image display apparatus according to claim 3, further comprising a function capable of adjusting a time from when the light source is turned on until a connection detection signal is validated.

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