JP2020020818A - Light source device and projection display device using the same - Google Patents

Abstract

To solve the problem that positional shift tends to arise between a capture position of a camera and a projection image depending on a projection distance when capturing a projection image and actions on the image with a camera, or capturing an image on the projection image, and performing corresponding processes, the problem being especially significant with ultra wide-angle projectors.SOLUTION: A projection display device is provided, comprising at least a projection optical system, and an image capturing unit. The projection optical system has a reflective surface having a finite focal length, and the image capturing unit is disposed on a side opposite the reflective surface when viewed from a projection surface.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a projector. In particular, it relates to a projector with an imaging device.

  In recent years, a projector that captures light from a screen and has additional functions such as a pointing device function and a photographing function based on the image information has been proposed. As such a projector, for example, there is a projector as disclosed in Patent Document 1.

JP 2012-234149 A

  Particularly in recent years, such projectors have been increasingly used in educational sites. In such a case, it is common to use a wide-angle, high-shift projection form in order to make effective use of the space around the narrow teaching platform and to prevent the faculty from dazzling the presentation.

  However, as shown in Patent Literature 1, when a technique of independently arranging the projection optical system and the imaging optical system is used, when the projection distance is changed, the range of projection and imaging greatly shifts depending on the distance. However, there is a problem that it is necessary to perform a calibration operation every time the device is re-installed.

In order to solve the above problems, the projection display device according to the present invention is,
An image display element,
A projection optical system for enlarging and projecting the image of the image display element on the projection surface,
An imaging device;
A projection display device comprising at least
The projection optical system has a reflecting surface having a finite focal length,
The imaging device is disposed on the opposite side of the reflection surface when viewed from the projection surface,
The reflection surface has a characteristic of reflecting projection light and transmitting imaging light.

  According to the present invention, it is possible to provide a projector that does not require calibration even if the projection distance changes and has an imaging system with a uniform resolution over the entire screen.

Configuration explanatory view of a projection imaging integrated optical system shown in an embodiment of the present invention Explanatory drawing of the optical characteristic of the reflective optical surface used in the embodiment of the present invention Explanatory drawing of the optical characteristic of the reflective optical surface used in the embodiment of the present invention Explanatory drawing of the optical characteristic of the reflective optical surface used in the embodiment of the present invention Explanatory drawing of the optical characteristic of the reflective optical surface used in the embodiment of the present invention FIG. 4 is an explanatory diagram of wavelength characteristics of a light source used in the embodiment of the present invention.

  Hereinafter, embodiments for implementing the present invention will be described with reference to the drawings.

(Example)
FIG. 1 is a schematic diagram illustrating a configuration of an embodiment of a projector with an imaging device according to the present invention.

  Reference numeral 1 denotes an image display element, which is illuminated by a light source and an illumination optical system (not shown), converts illumination light into image light corresponding to an image signal, and guides it to a projection optical system.

  The refracting optical system 2 and the reflecting optical surface 3 together form a projection optical system. The image light emitted from the image display device 1 enters the reflection optical surface 3 through the refraction optical system 2 and is reflected and projects an enlarged image of the image display device on a screen (not shown). In the present embodiment, the refractive optical system 2 is a lens having an intermediate image inside the lens, and achieves good aberration correction with a small-diameter lens while having a wide angle.

  On the other hand, the reflection optical surface 3 is a convex mirror, and the light after exiting the refraction optical system is further reflected at an increased angle of view to enhance the wide angle. With such a configuration, a wide-angle projection projector can be realized with a small size and high performance.

  On the other hand, an imaging lens 4 is arranged on the opposite side of the reflective optical surface 3 from the refractive optical system 2. The imaging lens 4 is installed so that its shooting direction substantially matches the projection direction of the projection optical system reflected by the refraction optical system 3. The reflecting optical surface 3 has such a property that a light beam emitted from the projection optical system is reflected, and light taken in by the imaging optical system is transmitted.

  2 and 3 show the reflection characteristics of the reflection optical surface 3 which realizes such a configuration.

  FIG. 2A shows a first example of the reflection characteristic of the reflection optical surface 3, which transmits infrared light and reflects visible light. The configuration of the present invention can be realized by setting the projection light beam to visible light and setting the sensitivity of the imaging device to infrared light. Although this configuration cannot image visible light, any polarization and wavelength can be used as projection light.

  FIG. 2B is a second example of the reflection characteristics of the reflection optical surface 3, and has a so-called polarization beam splitter characteristic of reflecting s-polarized light and transmitting p-polarized light. The configuration of the present invention can be realized by using s-polarized light for the projection light beam and p-polarized light for the imaging light. It is suitable when the projection light beam is polarized, such as in a liquid crystal projector.

  FIG. 2C shows a third example of the reflection characteristic of the reflection optical surface 3, which has a characteristic of a reflectance of about 50% in the entire visible region. Thus, it is possible to capture the imaging light while reflecting the projection light flux. This configuration has an advantage that the projection light flux and the imaging light flux do not need to depend on the wavelength or the polarization, and both can use the entire visible range.

  FIG. 3 shows a fourth example of the reflection characteristic of the reflection optical surface 3, which has a comb-shaped reflection characteristic in which the three primary colors of red, green, and blue are respectively divided into a transmission region and a reflection region. In this case, it is preferable that the light source of the projection optical system has a spectrum as shown in FIG. Specifically, such characteristics can be realized by using a laser light source or an LED light source. With such a configuration, light of three primary colors can be used for both the projection light and the imaging light.

  These are limited examples of the characteristics of the reflective optical surface 3. Naturally, the present invention is not limited to the above as long as it has characteristics of transmitting imaging light and reflecting projection light. Further, a characteristic such as a combination of the above examples is also possible.

  Now, in this embodiment, the reflecting optical surface 3 is configured as one surface of the concave meniscus lens 6. The concave meniscus lens 6 is an aspheric lens and forms a part of the optical system of the imaging optical system 4. That is, the reflecting optical surface 3 functions as a convex mirror as a projection optical system to exhibit the effect of expanding and reflecting light rays, and as an imaging optical system, realizes a wide angle as one surface of a concave meniscus lens. In other words, the projection optical system and the imaging optical system are shared via a surface having a refractive power, rather than simply combining them with a plane reflecting surface, thereby realizing a significant reduction in the number of components and space saving. Things.

  In the configuration of the present embodiment, since the imaging optical system and the projection optical system share the same axis, the imaging optical system always observes the same position even when the projection distance is changed, and the calibration is performed every time the camera is installed. You don't have to.

  The preferred embodiments of the present invention have been described above. However, it goes without saying that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist. For example, in this embodiment, the projection optical system and the imaging optical system are shared through the convex mirror, but by using different types of lens configurations, the projection optical system and the imaging optical system are shared with the concave surface as a mirror surface. It is possible to

1 image display element, 2 refraction optical system, 3 reflection optical system, 4 imaging optical system,
5 image sensor, 6 concave meniscus lens

Claims (11)

An image display element, a projection optical system for enlarging and projecting an image of the image display element onto a projection surface, and an imaging device, a projection display device including at least:
The projection optical system has a reflecting surface having a finite focal length,
The imaging device is disposed on the opposite side of the reflection surface when viewed from the projection surface,
The projection type display device, wherein the reflection surface has a characteristic of reflecting projection light and transmitting imaging light. The reflection surface is a mirror surface formed on one side of the lens element,
The surface opposite the reflection surface is a refraction surface,
A projection display device, wherein an imaging optical system of the imaging device includes the lens element. EP, the distance from the reflecting surface to the entrance pupil of the projection optical system,
When the distance from the reflecting surface to the entrance pupil of the imaging optical system is EC,
0.2 <EP / EC <2.0
A projection type display device characterized by the following.   The projection type display device, wherein the reflection surface has a property of transmitting infrared light and reflecting visible light.   The projection display device, wherein the reflection surface has a characteristic of reflecting s-polarized light and transmitting p-polarized light.   The projection type display device, wherein the reflection surface is a half mirror. The reflecting surface has both transmission characteristics and reflection characteristics in each of the three primary colors,
A projection display device, wherein a projection optical system uses a light source including a wavelength band having reflection characteristics.   The projection type display device, wherein the lens element is a concave meniscus lens having a convex reflecting surface.   The projection type display device, wherein the lens element is a lens having a concave reflecting surface.   The projection type display device, wherein the imaging optical system is an imaging lens including a concave meniscus lens closest to an object. An image display element, a projection optical system for enlarging and projecting an image of the image display element onto a projection surface, and an imaging device, a projection display device including at least:
The projection optical system and the imaging device share at least an optical element,
The imaging device is disposed on the opposite side of the optical element as viewed from the projection surface,
A projection display device, wherein the optical element has a characteristic of reflecting projection light and transmitting imaging light, and has a different effect on the projection light and the imaging light.