JP2006184359A - Projection display device and projection display method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a projection display device wherein a focusing mechanism is simplified. <P>SOLUTION: An image is projected to a screen through a projection lens 31. A control part 11 controls a projecting means to project a range-finding image scanning in a 1st direction to the screen. As the result of this projection, the range-finding image light reflected by the screen is received by an optical sensor 16. The optical sensor 16 is arranged in parallel to the optical axis of the projecting light, and also, in the 1st direction. A distance up to the screen is calculated by the control part 11 by introducing triangular range-finding on the basis of the output signal from the optical sensor 16, then, focusing is performed on the basis of the calculated distance. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a projection display apparatus and a projection display method for projecting and displaying an image on a screen.

In a projection display apparatus that has a transmissive display device or a reflective display device and projects an image displayed on the display device on a screen in an enlarged manner, a pair of line sensors is used as a mechanism for adjusting the focal length of the projection unit. There is a focal length adjusting mechanism using a modular passive sensor.
JP 05-188282 A JP 2004-125770 A

  The focal length adjustment mechanism using the above-described passive sensor needs to include two sets of a line sensor and an optical system for forming an image on the line sensor, so that the apparatus becomes complicated, large, and expensive. There was a problem of inviting.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a projection display apparatus and a focus adjustment method for the same, in which a focal length adjustment mechanism is simplified.

  In order to achieve the above object, in the present invention, a projection means for projecting an image on a screen, an image output means for projecting a distance measurement image to be scanned in the first direction from the projection means to the screen, A light receiving means provided on the screen in parallel with the projection optical axis of the image output means and receiving the distance measuring image light projected on the screen by the image output means and reflected by the screen; A processing unit that calculates a distance from the projection unit to the screen by triangulation based on an output signal of the light receiving unit and outputs a control signal based on the calculated distance; and a control output by the processing unit Provided is a projection display device comprising a driving unit for adjusting a focus of the projection unit based on a signal.

The present invention relating to the apparatus is also established as an invention relating to a method, and the present invention relating to a method is also established as an invention relating to an apparatus.
Further, the present invention relating to an apparatus or a method has a function for causing a computer to execute a procedure corresponding to the invention (or for causing a computer to function as a means corresponding to the invention, or for a computer to have a function corresponding to the invention. It can also be realized as a program (for realizing the program), and can also be realized as a computer-readable recording medium on which the program is recorded.

  In a projection display device using a transmissive display device or a reflective display device, the focus adjustment mechanism can be simplified.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
Embodiments of the present invention will be described below with reference to the drawings.
A configuration of a projection display device according to an embodiment of the present invention is shown in FIG.
A projection display device 10 according to an embodiment of the present invention includes a control unit 11, a memory 12, a video signal switching circuit 13, a video signal output circuit 14, a display element 15, an optical sensor 16, a temperature sensor 17, a motor drive circuit 18, It has components such as a motor 19, a focus ring 20, an operation unit 21, a projection lens 31, and a light receiving light guide 32.

  The control unit 11 is responsible for overall control of the projection display device 10, and is realized here using a microprocessor, according to a program stored in the memory 12, according to a processing procedure as shown in FIG. Using the principle of triangulation as shown, focus adjustment processing is executed by the output signal of one optical sensor 16.

  The memory 12 stores various data including a program executed by the control unit 11 and display image data. Here, in addition to the program including the focus adjustment processing routine of the processing procedure as shown in FIG. 5 and display image data, focus adjustment image data 12 a is stored in the memory 12.

  The video signal switching circuit 13 selects an image to be projected on the screen under the control of the control unit 11, and in accordance with the switching control signal (SEL) output from the control unit 11, the video signal generated inside the apparatus and the outside The supplied video signal (EXVD) is switched and output.

  The video signal output circuit 14 generates display drive image data based on the video signal output from the video signal switching circuit 13 and sends the generated image data to the display element 15.

  The display element 15 constitutes a projection unit together with the projection lens 31, and is a transmissive (for example, liquid crystal) or reflective (for example, DMD) display device that displays and outputs image data received from the video signal output circuit 14. .

  The optical sensor 16 constitutes a light receiving unit together with the light receiving light guide 32, and is provided after the elongated light receiving light guide 32 provided in parallel to the projection optical axis as shown in FIG. The light receiving light guide path 32 is provided with a light absorbing material or coating.

  At the time of focus adjustment, the control unit 11 projects a distance measurement image as shown in FIG. 4 from the display element 15 onto the screen from the projection lens 31. The projected image at this time is an image in which a vertical line-shaped distance measuring image is displayed on the screen and the vertical line is scanned left and right.

  Note that the present invention is not limited to this vertical line-shaped distance measuring image. For example, the same effect can be obtained even when the full screen is a white image and the full screen is a black image alternately appearing and flowing to the right side.

  The optical sensor 16 receives the distance measuring image light reflected by the screen by the light receiving element and outputs a signal according to the light reception to the control unit 11. Specifically, since the output of the signal increases when the vertical line is detected, it can be detected that the vertical line has reached the light receiving axis of the optical sensor 16.

  The control unit 11 has a scanning width Δx of the display element 15 when the optical sensor 16 detects a vertical line, a focal length f of the projection lens 31, and a baseline length B corresponding to the space between the projection lens 31 and the light inlet of the optical sensor 16. 2 is used to calculate the distance between the projection base point of the projection lens 31 and the point where the projection optical axis on the screen 40 intersects the screen surface by the triangulation shown in FIG. 2, and based on this calculated distance. A motor drive signal (MD) is generated, the motor 19 is driven, the rotational position of the focus ring 20 is controlled, and the focus of the projection lens 31 is adjusted.

  The temperature sensor 17 monitors the temperature of the optical sensor 16 having temperature characteristics, and sends this temperature detection signal to the control unit 11. The control unit 11 corrects the position signal output from the optical sensor 16 based on the temperature detection signal received from the temperature sensor 17.

  The motor drive circuit 18 drives and controls the motor 19 by the motor drive signal (MD) output from the control unit 11 to rotationally drive the focus ring 20, and controls the rotational position of the focus ring 20 to adjust the focus of the projection lens 31. I do. The control unit 11 calculates a table in which a focal length prepared in advance and a motor rotation number are associated with each other based on distance measurement data obtained by distance calculation described later, derives the motor rotation number, and a motor according to the rotation number A drive signal (MD) is generated, and the generated motor drive signal (MD) is sent to the motor drive circuit 18.

  The operation unit 21 has operation buttons operated by the user, and sends various instruction signals to the control unit 11 according to the operation of the operation buttons. Here, the controller 11 is notified of the start and end signals of focus adjustment according to the operation of the operation buttons.

As shown in FIG. 2, the projection lens 31 and the light inlet of the optical sensor 16 are arranged at a predetermined distance on the front surface of the housing of the projection display device 10.
FIG. 2 shows the distance measuring principle of the distance measuring mechanism using one optical sensor 16 in the embodiment of the present invention.
The optical sensor 16 and the optical path tube from the light intake port of the optical sensor 16 to the optical sensor 16 are modularized, placed parallel to the projection optical axis of the projection lens 31, and their relative positions are determined. This measurement principle is derived from triangulation, and there is a relationship of L: B = f: Δx because the two triangles in the shaded area are similar.

Therefore,
L = Bf / Δx (Formula 1)
It is.
here,
L is the distance between the light receiving axis from the light inlet of the optical sensor 16 to the optical sensor 16 and the point (A) where the screen surface intersects,
B is a distance corresponding to the distance between the projection lens 31 and the light receiving axis of the optical sensor 16;
f is the focal length of the projection lens 31,
Δx is a scanning width distance Δx when the optical sensor 16 detects a vertical line.
It is.
Δx can be obtained from the pixel density of the display element 15. Note that when the projection display device 10 is manufactured, the position of the center pixel of the display element 15 and the projection axis must be matched. Thus, an accurate value of Δx can be obtained.

  The distance L between the projection optical axis on the screen 40 and the point (A) where the screen surface intersects can be obtained from the distance B, the distance f, and the distance Δx. Using this distance measuring means, a distance measuring mechanism using only one line sensor is realized.

  In order to perform accurate distance measurement with this distance measuring mechanism, two triangles indicated by hatching in FIG. 2 must be two-dimensionally arranged. Therefore, in this embodiment, as shown in FIG. 3, a sensor module obtained by modularizing the light receiving light guide path 32 and the optical sensor 16 is arranged in accordance with the reference plane (s) based on the optical axis of the projection lens 31. Yes.

  Distance measurement by this distance measurement mechanism is performed using a distance measurement image. An example of this distance measurement image is shown in FIG. Here, a distance measuring image (Pv) having a vertical line shape is projected onto the center of the screen surface of the screen 40. This projected image is an image in which a vertical line-shaped distance measuring image is displayed on the screen and the vertical line is scanned left and right.

  The control unit 11 calculates the distance L shown in FIG. 2 according to the timing at which the optical sensor 16 receives the distance measuring image light reflected from the screen surface via the light receiving light guide 32, and calculates the calculated distance. Based on L, the focus of the projection lens 31 is adjusted.

The processing procedure of the projection display device 10 in the above embodiment is shown in FIG.
When power for operation is supplied to the projection display device 10, the control unit 11 follows the processing procedure shown in FIG. 5 according to the program stored in the memory 12, and the principle of triangulation as shown in FIG. The focus adjustment processing is executed by using the output signal of one photosensor 16.

  When the system power is turned on (power-on), the control unit 11 reads the focus adjustment image data 12a from the memory 12, and based on the focus adjustment image data 12a, the vertical line-shaped distance measurement as shown in FIG. The moving image (Pv) is projected onto the screen surface of the screen 40 (step S501).

  By projecting the vertical line-shaped distance measuring image (Pv) onto the screen 40, the distance measuring image light reflected from the screen surface enters the light receiving light guide path 32 and is received by the optical sensor 16.

The control unit 11
B: Distance corresponding to the distance between the projection lens 31 and the light receiving axis of the optical sensor 16;
f: the focal length of the projection lens 31;
Δx: scanning width distance Δx when the optical sensor 16 detects a vertical line
2, the distance between the projection base point of the projection lens 31 and the point where the projection optical axis on the screen 40 intersects the screen surface is calculated by the triangulation shown in FIG. 2, and the motor drive based on the calculated distance is performed. A signal (MD) is sent to the motor drive circuit 18, the motor 19 is driven to control the rotational position of the focus ring 20, and the focus of the projection lens 31 is adjusted (step S502).

  After the focus adjustment is completed (step S503), the control unit 11 follows the instruction operation from the operation unit 21 and outputs a video signal stored in the memory 12 or a video signal (EXVD) supplied from the outside to a video signal output circuit. The image displayed on the display element 15 based on this video signal is enlarged and displayed on the screen surface of the screen 40 (step S504). When an image display end instruction is received from the operation unit 21, the image display process ends (step S505), and the system power supply is shut off (powered off).

  According to the above-described embodiment, since only one optical system and a line sensor for distance measurement are provided, the overall configuration of the projection display device 10 can be simplified, thereby providing an autofocus function. The projection display device can be reduced in size, weight, and cost.

The block diagram which shows the structure of the projection type display apparatus which concerns on embodiment of this invention. The figure for demonstrating the ranging principle of the ranging mechanism which concerns on embodiment of this invention. The figure which shows the arrangement | positioning relationship of the projection lens and line sensor of the projection type display apparatus which concern on embodiment of this invention. The figure which shows an example of the moving image for ranging which concerns on embodiment of this invention. The flowchart which shows the process sequence of the projection type display apparatus which concerns on embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Projection type display apparatus, 11 ... Control part, 12 ... Memory, 13 ... Video signal switching circuit, 14 ... Video signal output circuit, 15 ... Display element, 16 ... Optical sensor, 17 ... Temperature sensor, 18 ... Motor drive circuit , 19 ... a motor, 20 ... a focus ring, 21 ... an operation unit, 31 ... a projection lens, 32 ... a light guide for light reception.

Claims (5)

Projection means for projecting an image on the screen;
Image output means for projecting a distance measuring image scanned in the first direction from the projection means to the screen;
A light receiving means provided on the screen in parallel with the projection optical axis of the image output means and receiving the distance measuring image light projected on the screen by the image output means and reflected by the screen; ,
Processing means for calculating a distance from the projection means to the screen by triangulation based on an output signal of the light receiving means, and outputting a control signal based on the calculated distance;
A projection type display apparatus comprising: a drive unit that adjusts a focus of the projection unit based on a control signal output from the processing unit.   The projection type display device according to claim 1, wherein the projection unit includes a display device that displays an image and a projection lens that enlarges and projects the image displayed on the display device onto the screen.   The light receiving means includes a light guide tube that is arranged side by side with the projection lens and guides distance measuring image light reflected by the screen, and an optical sensor that photoelectrically converts light from the light guide tube. 2. The projection display device according to 2.   The processing means calculates a distance corresponding to the distance between the image output means and the light receiving axis of the light receiving means, the focal length of the projection lens, and the distance of the scanning width on the light receiving means when the light receiving means detects the vertical line. The projection type display device according to claim 3, further comprising: Project the image on the screen by the projection means,
The image output means causes the projection means to project a distance measuring image to be scanned in the horizontal direction on the screen,
Ranging image light projected on the screen by the image output means and reflected by the screen is received by a light receiving means provided in parallel with the projection optical axis of the image output means,
The processing means calculates the distance from the projection means to the screen by triangulation based on the output signal of the light receiving means, and outputs a control signal based on the calculated distance,
A projection type display method comprising: adjusting a focus of the projection unit based on a control signal output from the processing unit by a driving unit.

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