KR20140106911A

KR20140106911A - Display Device

Info

Publication number: KR20140106911A
Application number: KR1020130021185A
Authority: KR
Inventors: 이종권; 이광민
Original assignee: 엘지전자 주식회사
Priority date: 2013-02-27
Filing date: 2013-02-27
Publication date: 2014-09-04

Abstract

A light source unit for emitting light; An image projection unit for synthesizing light emitted from the light source unit with image information and projecting an image; A sensor for detecting presence or absence of an obstacle in a projection path of an image projected from the image projecting unit; A Fresnel lens coupled to an upper portion of the sensor and having a fine pattern formed therein; And a controller for reducing the intensity of the light emitted or stopped when the obstacle is detected by the sensor, the display device is not exposed to the light emitted from the display device, .

Description

[0001]

The present invention relates to a display device capable of preventing a user from being exposed to a light source.

A projector, a projection system, and the like are display devices that project an input image signal on a screen to display an image.

Such a display device is mainly used for presentation of a conference room, a projector of a theater, a home theater of a home, and the like. A recent display device is mostly a liquid crystal display (LCD), and a cathode ray tube (CRT) may be used.

Conventionally, in order to realize a large screen, an image appearing on an LCD and a CRT is enlarged by a lens and then projected onto a screen.

In recent years, a display device using a digital micro-mirror display (DMD) panel and a laser is used for a clear image quality.

An object of the present invention is to provide a display device capable of detecting the presence of an obstacle in the emission direction of light emitted from a display device and controlling the light not to be directly incident on the obstacle.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, unless further departing from the spirit and scope of the invention as defined by the appended claims. It will be possible.

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, An image projection unit for synthesizing light emitted from the light source unit with image information and projecting an image; A sensor for detecting presence or absence of an obstacle in a projection path of an image projected from the image projecting unit; A Fresnel lens coupled to an upper portion of the sensor and having a fine pattern formed therein; And a control unit for reducing the intensity of light emitted or emitted from the light source when an obstacle is sensed by the sensor.

The sensor is one, and the horizontal center axis of the detection range of the sensor can coincide with the horizontal center axis of the image projection area of the image projection unit.

One of the sensors may be provided on the left or right of the image projecting unit, and the horizontal center axis of the sensing range of the sensor may be inclined toward the center.

The angle sensed by the sensor may range from 110 degrees to 180 degrees in the horizontal direction.

The sensor may include a pair of elements spaced apart in a direction parallel to the screen, and a Fresnel lens divided into a plurality of sections in a direction parallel to the screen may be used.

The sensor may use a PIR sensor (Pyro-electric Infra-red sensor).

Wherein the image projecting unit comprises: a micro device for synthesizing light and image information; And a reflector for reflecting the image emitted from the micro device toward the screen.

The reflective portion may be in the form of a concave mirror.

The sensors may be positioned on the left and right of the image projection unit, respectively.

The horizontal center axis of the detection range of each of the sensors may be arranged on both sides of the horizontal center axis of the image projection unit of the image projection unit and may not intersect with each other.

According to at least one embodiment of the present invention, a user is not exposed to light emitted from a display device, thereby preventing a problem such as a reduction in visual acuity due to light.

Since the infrared sensor has a wide sensing range, it is possible to prevent the user from being exposed to light even if only one sensor is provided, thereby minimizing the cost added by the sensor.

The effects obtained by the present invention are not limited to the above-mentioned effects, and other effects not mentioned can be clearly understood by those skilled in the art from the following description will be.

1 is a perspective view showing an embodiment of a display device of the present invention.
2 is a conceptual diagram showing an internal configuration of a display device of the present invention.
3 is a perspective view showing the use state of one embodiment of the display device of the present invention.
4 is a plan view showing one embodiment of the display device of the present invention.
5 is a side view showing one embodiment of the display device of the present invention.
6 is a plan view showing another embodiment of the display device of the present invention.
7 is a side view showing another embodiment of the display device of the present invention.
8 is a plan view showing still another embodiment of the display device of the present invention.
9 is an exploded perspective view showing an embodiment of a sensor unit of a display device of the present invention.
10 is a perspective view showing a Fresnel lens of a display device of the present invention.

Hereinafter, a mobile terminal related to the present invention will be described in detail with reference to the drawings. The suffix "module" and " part "for the components used in the following description are given or mixed in consideration of ease of specification, and do not have their own meaning or role.

1 is a perspective view schematically illustrating a configuration of the display device 100 according to an embodiment of the present invention. FIG. 2 is a plan view schematically illustrating the configuration of the inside of FIG. 1, An image projection unit 120 for synthesizing the received light and image information and projecting the image, a sensor 140 for detecting the presence of an obstacle, and a control unit (not shown). Display device 125

The light source 110 is composed of a plurality of lamps 111 and emits light generated from the lamps 111. The lamp 111 may be a light emitting diode (LED) or the like. In order to increase the intensity and intensity of light, a laser diode (LD) Can be used as a light source.

The laser used as a light source has good monochromaticity, directivity and light condensing property, and is a useful light source for display devices due to its high luminance. By transferring image information by laser, a high-brightness, clear image can be realized even on a large screen. Thanks to this technique, the size of the laser display device can be greatly reduced.

The light emitted from the lamp 111 is selectively reflected through the anisotropic mirror 112 and is emitted to the image projection unit 120.

The image projection unit 120 may include an image synthesis unit 124 and a reflection unit 125 including a micro device 121, a prism 122, and a projection lens 123. The microdevice 121 may reflect the supplied light in units of pixels to realize a different color for each pixel.

As the micro device 121, a digital micromirror display, a liquid crystal display (LCD), and a liquid crystal on silicon (LCoS) that operate in a digital manner can be used.

Digital micromirror displays are capable of obtaining high-resolution, clear images by allowing fine mirrors to switch more than a thousand times per second to selectively reflect or not reflect light. Because it is 100% digitally controlled, there is no need to convert the gamma signal or pass the processed digital signal through the digital / analog converter like an analog display device.

A liquid crystal display device is a device that injects liquid crystal between two thin glass substrates and applies a voltage to each pixel to change the arrangement of liquid crystal molecules to selectively transmit or reflect light to synthesize light and image information.

A silicon liquid crystal display device is a display device in which a glass substrate of a liquid crystal display device is replaced with a silicon wafer and a circuit is formed thereon. It is possible to realize a brighter picture with the same light quantity as that of the liquid crystal display device and has a fast response speed. A prism 122 may be used to distinguish the light supplied to the micro device 121 from the path of the emitted light. The prism 122 differs in refractive index from air to transmit light supplied from the outside but reflects light emitted from the micro device 121 to change the path of light. The projection lens 123 may be used to adjust the sharpness, size, focus, and image quality of an image projected from the micro device 121. [

The light synthesized by the image synthesizing unit 124 and the image information may be directly supplied to the screen 200, but may be supplied to the reflection unit 125. The reflecting portion 125 may be a flat mirror shape, but a hemispherical concave mirror as shown in Fig. 2 may be used. The light reflected by the reflective portion 125 is emitted toward the screen 200 as shown in FIG.

As shown in FIG. 3, in recent years, a monochromatic display device 100 capable of realizing a large screen by projecting from a short distance is widely used. Since the single focus display device 100 realizes a large screen at a short distance, the image projection area A has a wider projection angle? As compared with the conventional display device 100, as shown in FIG.

Since the short focus display device 100 can realize a large screen at a short distance, a user can stand at a position more distant from the display device 100 on the screen 200 in a conventional method, You do not have to look.

Since the user is not directly exposed to light, a laser can be used as the light source 110. The laser is a high-density light, which can achieve a clearer color and longer life than conventional LED light sources. However, the user may approach the screen 200 during the image projection or may mistakenly enter the image projection area A.

In this case, when a person is exposed to light, there is a problem such as deterioration in visual acuity. Particularly, when a laser is used, the wavelength is shorter than that of a general light source 110 and may have a bad influence on the human body because it is a high energy light source . Accordingly, if it is detected that the user enters the image projection area A, the operation of the light source 110 may be interrupted to stop the supply of light or weaken the intensity of the light emitted from the light source 110, or It is possible to switch to a light source 110 which is safe for a person.

In the present invention, it is possible to detect whether or not an obstacle has entered the projection area using the sensor 140. In the present invention, an infrared sensor may be used as the sensor 140, and a Pyro-electric Infrared (PIR) sensor 140 capable of sensing a human body temperature may be used.

Since the PIR sensor 140 detects motion of an object at a predetermined temperature or higher, it can only detect obstacles such as a person or an animal, and the display device 100 operates normally when another object enters the image projection area A.

9 is an exploded perspective view of the PIR sensor 140. Inside the metal case 143 having the window 144 serving as a polarization filter, there is at least one element 141 for detecting infrared rays. If there is only one element 141, there is a large error, and if there is a difference between the values detected by one or more elements 141, it is judged that a person or an animal moves.

When two elements 141 are used, they can be arranged in a direction parallel to the screen 200 in this embodiment. This is because it is easy to sense horizontal movement and the image projection area A is larger in horizontal direction.

The sensor 140 may include one or more sensors 140.

4 and 5 show an embodiment of a display device 100 having two sensors 140 and FIGS. 6, 7 and 8 show an embodiment of a display device 100 having a sensor 140 to be. As the number of the sensors 140 increases, the detection range increases. However, since the cost increases as the number of the sensors 140 increases, it is possible to detect all of the image projection areas A with as few sensors 140 as possible .

A hemispherical Fresnel lens 145 may be used on the front surface of the sensor 140 to sufficiently sense the image projection area A with a small number of sensors 140. [ The Fresnel lens 145 can be made into a large-diameter lens without making the thickness thinner. And a plurality of circles having different diameters in the center of one are formed in the shape of a band 146. The center of the circle band 146 may be provided in a single Fresnel lens 145.

The Fresnel lens 145 enlarges the sensing distance, improves the sensitivity of the sensor 140, and further protects the sensor 140 to block the influence of outside wind and external light.

10 is a perspective view showing one embodiment of the Fresnel lens 145. The Fresnel lens 145 has a plurality of circular bands 146 formed therein. In particular, the Fresnel lens 145 of the present invention is partitioned into a plurality of regions 147. The partitioned area 147 of the Fresnel lens 145 is also divided in the direction parallel to the screen 200 when the element 141 is disposed in a direction parallel to the screen 200. [ That is, the line partitioning each region 147 is perpendicular to the screen 200 (y-axis direction). The Fresnel lens 145 having such a structure divides an area sensed by the two elements 141 to extend the sensing range B.

The sensing range B sensed by the sensor 140 to which the Fresnel lens 145 is attached to the PIR sensor 140 can sense a wide area of about 120 degrees or more in the horizontal direction.

Figs. 4 and 5 are a plan view and a side view, respectively, of an embodiment having two sensors 140, Figs. 6 and 7 are a plan view and a side view of an embodiment having one sensor 140, Lt; RTI ID = 0.0 > 140 < / RTI >

When two sensors 140 are provided, one sensor may be disposed on the reflective portion 125 in the x-axis direction so that all the obstacles located in the image projection area A spread widely in the lateral direction can be detected. In this embodiment, since the reflection unit 125 is included, the sensors 140 can be disposed on the left and right sides of the reflection unit, respectively.

4, the horizontal center axis of the sensing range B of each of the sensors 140 is disposed in parallel to the left and right of the image projection horizontal center axis of the reflection unit 125 so as to be parallel or at least not intersect with each other.

When two or more sensors 140 are used, most obstacles in the image projection area A can be detected. However, when the angles of the two or more sensors 140 are changed or when the angles of the two or more sensors 140 are largely different from each other, the sensing range B becomes wider than the image projection area A, There is a problem that the light source 110 is controlled until it is positioned.

Therefore, as shown in FIG. 4, it is preferable for horizontally arranging the sensor 140 to horizontally align the image projection area A so that the image projection area A and the sensing range B substantially coincide with each other.

The sensor 140 may also be oriented upward so that the image sensing area A and the sensing area B substantially coincide with each other as in the case of the vertical direction as shown in FIG. .

When the sensor 140 is mounted on the screen 200 so that the sensor 140 and the reflecting portion 125 are positioned on the same line in the vertical direction on the screen 200, It is possible to arrange it on the rear side of the reflecting portion 125 as a reference.

Even if the horizontal range? Of the sensing range B is smaller than the horizontal range? Of the image projection area A when the sensor 140 is disposed behind the reflective portion 125, Similarly, the sensing range B can cover most of the image projection area A.

The sensing range B can sense more than 80% of the image projection area A with only one sensor 140 although there is a difference depending on the distance between the reflection part 125 and the sensor 140. [

6, the horizontal center axis of the sensing range B of the sensor 140 is parallel to the horizontal axis of the image projection area A of the reflection part 125, Coincides with the central axis. Since the sensor 140 is provided at a position spaced apart from the screen than the reflective portion 125, the sensing range B can be arranged to face downward than the embodiment of FIG. 5 in order to cover most of the image projection area A. have.

Alternatively, the sensor 140 may be provided on only one side of the reflective portion 125 as in the embodiment shown in FIG. In this case, the sensing range of the sensor is shifted to one side, so that the sensor 140 is preferably arranged such that the horizontal central axis of the sensing area B is inclined toward the center of the image projection area A in the horizontal direction.

By tilting to one side, both sides of the image projection area A can be detected. Although not shown in the drawing, if the sensor 140 is disposed behind the reflection unit 125 as shown in FIG. 6, the detection range can be extended. Since the sensing area B on the side of the present embodiment is the same as the embodiment of FIG. 5, a detailed description thereof will be omitted.

As described above, according to at least one embodiment of the present invention, the user is not exposed to the light emitted from the display device 100, thereby preventing a problem such as a decrease in visual acuity due to light.

The infrared sensor 140 can prevent the user from being exposed to light even if the detection range B is wide and only one is provided, thereby minimizing the additional expense of having the sensor 140.

It will be apparent to those skilled in the art that the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof.

Accordingly, the above description should not be construed in a limiting sense in all respects and should be considered illustrative. The scope of the present invention should be determined by rational interpretation of the appended claims, and all changes within the scope of equivalents of the present invention are included in the scope of the present invention.

100: display device 105: case
110: light source 111: lamp
112: anisotropic mirror 120: image projection section
121: Micro device 122: Prism
123: projection lens 125:
140: sensor 143: metal case
141: Element 145: Fresnel lens
146: fine pattern 200: screen
A: Image projection area B: Detection area

Claims

A light source unit for emitting light;
An image projection unit for synthesizing light emitted from the light source unit with image information and projecting an image; A sensor for detecting presence or absence of an obstacle in a projection path of an image projected from the image projecting unit;
A Fresnel lens coupled to an upper portion of the sensor and having a fine pattern formed therein; And
And a controller for decreasing the intensity of light emitted or emitted from the light source when an obstacle is detected by the sensor.

The method according to claim 1,
The sensor is one,
Wherein a horizontal center axis of the detection range of the sensor coincides with a horizontal center axis of the image projection area of the image projection unit.

The method according to claim 1,
The sensor is provided on the left or right side of the image projecting unit,
And the horizontal center axis of the detection range of the sensor is inclined toward the center.

The method according to claim 1,
Wherein the angle detected by the sensor is not less than 110 DEG and not more than 180 DEG in a horizontal direction.

The method according to claim 1,
The sensor comprising a pair of elements spaced apart in a direction parallel to the screen,
Wherein the Fresnel lens is divided into a plurality of sections in a direction parallel to the screen.

The method according to claim 1,
Wherein the sensor is an infrared sensor (PIR sensor: Pyro-electric InfraRed seonsor).

The method according to claim 1,
Wherein the image projecting unit comprises:
A micro device for synthesizing light and image information; And
And a reflector for reflecting the image emitted from the micro device toward the screen.

8. The method of claim 7,
Wherein the reflective portion has a concave mirror shape.

The method according to claim 1,
Wherein the sensors are positioned on the left and right sides of the image projection unit, respectively.

10. The method of claim 9,
Wherein the horizontal center axis of the detection range of each of the sensors is arranged on both sides of the horizontal center axis of the image projection unit of the image projection unit so as not to intersect with each other.

The method according to claim 1,
Wherein the light source unit includes a laser diode emitting laser light.