JPH03141336A - Projection type display device - Google Patents

Abstract

PURPOSE:To match a variable magnification ratio to a prescribed screen size with an easy operation by providing a focusing means, the screen size inputting means specifying the size of a projection screen where light is projected, and a lens position control means. CONSTITUTION:A projection type display device is provided with the focusing means 1 which finds a range between projection surfaces and moves the focusing system lens of the projection lens to a focusing position, and the screen size inputting means 6 which specifies the size of the projection screen where the light is projected. Further, the projection type display device is provided with a lens position control means 7 which moves a variable power lens so as to obtain a specified screen size based on the screen size information from the screen size inputting means 6 and a range-finding information from the focusing means 1. Thus, an automatically focused screen can be obtained even if a screen is big or small, with only the easy operation of specifying the size of the screen, and a video screen, etc., are appreciated in a short time after a device is set.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a projection display device that projects an image onto a screen or the like.

[Prior Art] Conventionally, as shown in FIG.
Transmissive liquid crystal plates 10, 11, each driven by a signal.
Illumination system 19 includes an illumination lamp 12, a concave lens 18, etc.
A projection type display device is known in which the illumination system 1
9 light is green due to dichroic mirror 16.17,
Blue light is reflected, and infrared light is reflected by cold mirror 15. 13 and 14 are total reflection mirrors, and 8 is a dichroic prism.

Among such projection display devices, there is also known a projection display device in which the projection lens 20 is a variable focal length lens, and the projection screen is variable at the same projection distance.

[Problems to be Solved by the Invention] When the above-mentioned projection type display device has a projection lens with a variable focal length, when trying to project onto a projection screen of a specified size, it is necessary to measure the screen size after focusing. However, I had to go through the steps of adjusting the desired screen size by operating the variable focal length magnification control ring, which was a hassle.

An object of the present invention is to provide a projection display device whose magnification can be adjusted to a desired screen size with simple operations.

[Means for Solving the Problems] The gist of the present invention is to provide a projection type display device that projects image light onto a projection surface via a variable focal length projection lens. a focusing means for measuring the distance between the projection lenses and moving the focusing system lens of the projection lens to a focusing position; a screen size manual means for specifying the size of the projection screen to be projected onto the projection surface; The present invention is characterized by comprising a lens position control means for moving the variable magnification lens to obtain a designated screen size based on screen size information from the size input means and distance measurement information from the focusing means. Located on a projection display device.

[Operation] The projection type display device configured as described above can automatically create a focused screen from a small screen to a large screen by simply specifying the screen size.

Embodiment FIG. 1 is a diagram showing an embodiment of a projection type display device according to the present invention.

The projection optical system of the projection display device of this embodiment includes an illumination lamp 1.
The illumination light of the illumination system consisting of 9 mag.
7 and total reflection mirrors 13, 14, and 15 separate the illumination light into R and G%B and guide it to liquid crystal plates 10 and 11.12 for R2O and B, and the image on the liquid crystal plate 10, 11, and 12 is reflected by a dichroic prism 9. The images are combined and projected onto a screen (not shown) using a projection lens 20 of a variable focal length lens composed of lens groups of a focus lens 3, a variable magnification lens 4, and a convencator lens 5.

Reference numeral 6 denotes a screen size input section for inputting the screen size to be specified, and it may be configured with selection buttons such as 40 inches or 100 inches, or may be configured to allow continuous specification using a lever.

Alternatively, numbers may be entered manually using a numeric keypad.

Reference numeral 1 denotes an automatic focus detection device, which measures the distance to the screen using, for example, a triangulation method, and uses that information to drive the focus lens 3 with a focus lens drive actuator 2 to focus.

The distance information of the automatic focus detection device 1 and the information of the projection screen size inputted by the human power section 6 are inputted to the calculation section 7 consisting of a microcomputer, and the calculation section 7 calculates the variable magnification lens 4 of the projection lens 2o and the compensator 5. The position is calculated, the variable power lens 4 and the compensator 5 are driven by the variable power lens driving actuator 8, and the screen size is automatically set to a specified size.

Note that functions (1) and (2) described below may be added to this embodiment.

(1) When it is calculated that the projection screen size input at the input unit is impossible based on the focal length range of the projection lens and the distance information of the automatic focus detection device 1 (for example, if a large screen size is specified even though the distance is short, Alternatively, in order to indicate a small screen size even though it is a long distance, a signal indicating an image such as "impossible" may be added to the screen video signal using a known method.

(2) In the projection display device of the present invention, the larger the projection screen is, the darker the screen brightness becomes, and if the outside world is bright, the projected image becomes difficult to see. Therefore, a photometric device that measures the brightness of the outside world may be provided, and a limit may be set on the maximum screen size depending on the brightness of the outside world.

The operation of this embodiment described above will be explained based on the flowchart shown in FIG.

When you specify the screen size and perform distance measurement, based on the distance information,
On the one hand, it drives the focus lens and performs the focusing operation, and on the other hand, it calculates the focal length in conjunction with the screen size.
Roughly determine the positions of the variable magnification lens and compensator and drive them to set the desired screen size.

In addition, generally the object distance ms and the focal length f are S=f,
(There is a relationship of 1+.''+HH. In other words, m=L/j2.L Niscreen size, p: Liquid crystal plate size, and HH is the principal point spacing, but since HH'<S, it can be ignored.

Therefore, the focal length is calculated from S and m.

[Effects of the Invention] As explained above, according to the present invention, the screen size can be set to 50 inches, for example, by manual screen size means.
By simply specifying the screen size, you can quickly adjust the screen size and project the image, and even if you set the distance between the device and the screen arbitrarily, you can immediately obtain the desired screen size. This makes it possible to view screens such as video screens in a short time after setting up the device.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of a projection type display device according to the present invention, FIG. 2 is a diagram showing a conventional projection type display device, and FIG. 3 is a flowchart explaining the operation of the embodiment shown in FIG. 1. It is. 1... Focus detection device 2... Focus lens drive actuator 3...
-Focus lens 4...variable magnification lens 5...convenzer 6...screen size input section 7...calculation section 8...
Actuator 9 that drives the variable magnification lens and compensator...Dichroic prism 10.11.12...Liquid crystal plate 13.14.15...Mirror 16.17...Dichroic mirror 19...Illumination system 4 people Figure 2 Figure 1

Claims (1)

[Claims] 1. In a projection display device that projects image light onto a projection surface via a projection lens with a variable focal length, the distance between the projection surfaces is measured and the focusing system lens of the projection lens is a focusing means for moving the screen to a focusing position; a screen size input means for specifying the size of the projection screen to be projected onto the projection surface; and screen size information from the screen size input means and distance measurement from the focusing means. 1. A projection type display device comprising: a lens position control means for moving a variable magnification lens so that a specified screen size is achieved based on the information.