JP2000019637A - Projection type display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a projection type display device which is capable of controlling projected images without causing complication of the structure in the device and may be immediately reset after the control of the projected images. SOLUTION: The projection type display device 1 has an object detecting means 50 which is disposed to face a projection screen 100 and a projected image control means 70 which controls the projected image on the projection surface 100 according to the output of this object detecting means 50. This projected image control means 70 has a signal switching circuit 71 which switches the image signal constituting image information to an image control signal to the extent of displaying the prescribed image when the signal to the extent that the object P is detected from the object detecting means 50 is inputted thereto. Since the projected image is changed to the dark and displayed by switching of the image signal, the simple resetting of the device is made possible without causing the complication of its structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light source lamp, an optical system for optically processing a light beam emitted from the light source lamp to form an optical image in accordance with image information, and an optical system for displaying the optical image on a projection surface. The present invention relates to a projection display device provided with a projection lens that performs enlarged projection.

[0002]

2. Description of the Related Art Conventionally, a light source lamp, an optical system for optically processing a light beam emitted from the light source lamp to form an optical image according to image information, and a projection for enlarging and projecting the optical image on a projection surface A projection display device having a lens is used. According to such a projection display device, a display screen of a computer or the like can be displayed on a large screen on the projection surface, and a multi-presentation for a large number of people can be performed. In the projection display device described above, since the image is enlarged and projected on the projection surface, it is preferable to increase the light amount of the light source lamp in order to display a clear image.
However, in a projection display device that emits such a strong light beam, looking into the projection lens while a projected image is being displayed may damage the eyes due to the strong light beam.

For this reason, an object detecting means is provided on the side surface of the outer case facing the projection surface, and when the object detecting means detects that an object has entered the area of the projected image, the projected image control means causes the object to be projected on the projection surface. (Japanese Utility Model Application Laid-Open No. 3-94888) has been proposed.

[0004]

However, the conventional projection display device having such an object detecting means and a projected image control means has the following problems.

The above-mentioned conventional projection image control means includes:
When an object is detected by the object detection means, a shutter is operated via a drive circuit to block an optical path inside the projection display device with the shutter. But,
If the projection image is blocked by such a shutter, a shutter, a shutter drive circuit, and the like must be separately provided inside the apparatus, which leads to a complicated structure inside the apparatus.
There is a problem that the size of the projection display device cannot be sufficiently reduced. Also, while the projection image is blocked by such a shutter, there is a problem that the shutter is heated by the light beam emitted from the light source lamp, and the temperature inside the projection display device increases.

Further, as the above-mentioned conventional projection image control means, there is also a projection image control means which shuts off the power supply to the light source lamp and turns off the light source lamp when an object is detected by the object detection means. Proposed. However, the projection display device is generally configured such that once the light source lamp is turned off, it cannot be turned on again until the light source lamp is cooled. Accordingly, in the projection image control means for turning off the light source lamp, even after removing the object in the projection area immediately after the operation of the projection image control means, the light source lamp is not sufficiently cooled because the light source lamp is not sufficiently cooled, and the projection image is restored. You may not be able to.

An object of the present invention is to provide a light source lamp, an optical system which optically processes a light beam emitted from the light source lamp to form an optical image according to image information, and enlarges the optical image on a projection surface. In a projection display device having a projection lens for projecting, a projection display device that can control a projection image without complicating the internal structure of the device and that can immediately return after controlling the projection image. It is to provide a device.

[0008]

A projection display apparatus according to the first invention of the present application forms a light source lamp and an optical image according to image information by optically processing a light beam emitted from the light source lamp. An optical system, and a projection display device provided with a projection lens for enlarging and projecting this optical image on a projection surface, an object detection means provided to face the projection surface,
A projection image control unit that controls a projection image displayed on the projection surface according to an output of the object detection unit,
The projection image control means, when a signal indicating that an object is detected is input from the object detection means, a signal for switching an image signal constituting the image information to an image control signal for displaying a predetermined image. It is characterized by comprising a switching circuit.

Here, the object detecting means is a concept including all means capable of outputting a warning signal to the effect that an object has entered the projection area of a projected image. In particular,
The object detecting means transmits an ultrasonic signal from an optical sensor for distance measurement including a light emitting unit and a light receiving unit, a pyroelectric infrared sensor for detecting a human body temperature of a person who has entered the projection area, and a transmitting element, It can be configured to include any of an ultrasonic sensor or the like that receives the reflected wave with the receiving element.

According to the present invention, since the projection image control means includes the signal switching circuit, a warning signal indicating that an object has entered the projection area is input from the object detection means. Then, the projection image is immediately switched to a predetermined image, for example, a black image, and the display on the projection surface is darkened. Therefore, without providing a dedicated member for controlling the projected image such as a shutter and a shutter driving circuit, the image signal processing circuit for processing an image signal input from a video terminal or the like is simply provided with a simple signal switching circuit to perform projection. Since the image control means can be configured, the structure inside the device is not complicated. Further, since the normal projection image is switched to a predetermined image such as a black image by the signal switching circuit, the temperature inside the apparatus does not increase due to the heating of the shutter unlike the conventional projection image control means. Further, since the projection image is switched by the signal switching circuit, the switching between the projection image and the black image can be easily and quickly performed, and even after the projection image is controlled by the projection image control means, the switching is quick. The image can be returned to the normal projection image.

In the above, the above-mentioned projection image control means is provided with a control state display circuit for displaying, when the object detection means detects that an object has entered the projection area of the projection image, a message to that effect. preferable.

That is, since the projection display device has the control state display circuit, the state in which the projection image control means is executed is confirmed, and the projection image display device is controlled to display the projection image. Discrimination with control can be easily performed.

A projection display apparatus according to a second aspect of the present invention includes a light source lamp, an optical system for optically processing a light beam emitted from the light source lamp to form an optical image according to image information, And a projection display device having a projection lens for enlarging and projecting the optical image on a projection surface, wherein the object detection means is provided to face the projection surface, and according to an output of the object detection means, Projection image control means for controlling a projection image displayed on a projection surface, wherein the projection image control means, when a signal indicating that an object is detected is input from the object detection means, And a lamp brightness changing circuit for lowering the brightness of the lamp.

According to the second aspect of the invention, since the projection image control means includes the lamp luminance changing circuit, when the object detection means detects that a person or the like has entered the projection area of the projection image, the lamp luminance is changed. And the intense luminous flux acting on the eyes of a person who has entered the projection area can be prevented. Further, since the projection image control means only changes the brightness of the light source lamp, the brightness of the light source lamp can be restored to an appropriate brightness immediately after the object detecting means detects that the intruding object has disappeared.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

(1) Overall Configuration of Apparatus FIG. 1 is a block diagram showing the structure of a projection display apparatus according to a first embodiment of the present invention.

The projection display device 1 includes a light source lamp 81
The light flux emitted from the light source is separated into three primary colors of red (R), green (G), and blue (B), and the light flux of each of these colors is modulated according to image information through a modulation element such as a light valve. It is of a type that is enlarged and displayed on the projection plane 100 through the display. The projection display device 1 electrically connects the light source lamp 81 and the optical unit 10 housed inside the outer case 2, the projection lens 6 provided to protrude forward of the outer case 2, and the light source lamp 81 and the optical unit 10. It is configured to include a circuit board to be controlled, a light source lamp 81, an optical unit 10, and a power supply unit (not shown) for supplying power to the circuit board. The projection display apparatus 1 includes an object detection unit 50 that detects an object P in the projection area A of the projection surface 100, a detection start determination unit 60 that determines the start of the detection by the object detection unit 50, and a projection image. Control means 70 is provided.

The light source lamp 81 constitutes a light source portion of the projection display device 1 and is integrated with a reflector by a lamp housing to constitute a light source lamp unit 8 (described later). Although not shown in FIG. 1, the light source lamp unit 8 is configured to be detachable from a lamp replacement lid provided on the bottom surface of the outer case 2. Everything can be replaced.

The optical unit 10 is a unit for optically processing a light beam emitted from the light source lamp 81 to form an optical image corresponding to image information.
Color separation optical system 924, light modulation system 925, color synthesis optical system 9
10. The illumination optical system 923 and the color separation optical system 924 are housed inside upper and lower light guides where a predetermined optical path is secured. It is sandwiched and held by the light guide. On the other hand, the light modulation system 925 and the color combining optical system 910 are arranged behind the optical path of the color separation optical system 924, and are mounted and fixed on a head body (not shown) to which the projection lens 6 is fixed.

(2) Structure of Optical System Next, the structure of the optical system of the projection display device 1 will be described with reference to the schematic diagram shown in FIG.

The illumination optical system 923 includes a reflection mirror 931 that bends the optical axis 1a of the light beam W emitted from the light source lamp unit 8 toward the front of the apparatus, and a first lens plate 921 that is disposed with the reflection mirror 931 interposed therebetween. And a second lens plate 922. The first lens plate 921 has a plurality of rectangular lenses arranged in a matrix, and divides a light beam emitted from a light source into a plurality of partial light beams. Then, each partial light beam is collected near the second lens plate 922.

The second lens plate 922 has a plurality of rectangular lenses arranged in a matrix, and converts each partial light beam emitted from the first lens plate 921 into a light modulation system 925.
Of liquid crystal light valves 925R, 925G, 92
5B (described later).

As described above, in the projection display apparatus 1 of the present embodiment, the liquid crystal light valve 925 is
Since the R, 925G, and 925B can be illuminated with light having substantially uniform illuminance, a projection image without illuminance unevenness can be obtained.

The color separation optical system 924 includes a blue-green reflecting dichroic mirror 941 and a green reflecting dichroic mirror 9.
42 and a reflection mirror 943. First, in the blue-green reflecting dichroic mirror 941, the blue light beam B included in the light beam W emitted from the illumination optical system 923 is used.
The green light flux G is reflected at a right angle, and travels toward the green reflection dichroic mirror 942.

The red light beam R passes through the blue-green reflecting dichroic mirror 941, is reflected at a right angle by the rear reflecting mirror 943, and is emitted from the emission unit 944 of the red light beam R to the prism unit 910 side. Next, of the blue and green luminous fluxes B and G reflected by the blue-green reflecting dichroic mirror 941, the green reflecting dichroic mirror 94
In 2, only the green light flux G is reflected at a right angle, and is emitted from the emission part 945 of the green light flux G to the color combining optical system side. The blue light beam B that has passed through the green reflection dichroic mirror 942 is transmitted from the light emitting system 946 of the blue light beam B to the light guide system 9.
The light is emitted to the side 27. In this example, the distances from the light emitting portion of the light beam W of the illumination optical system 923 to the light emitting portions 944, 945, and 946 of the color light beams in the color separation optical system 924 are all set to be equal.

The red and green luminous flux R of the color separation optical system 924,
Condensing lenses 951 and 952 are arranged on the emission sides of the G emission sections 944 and 945, respectively. Therefore,
The red and green luminous fluxes R and G emitted from the respective emission sections are incident on these condenser lenses 951 and 952 and are parallelized.

The red and green luminous fluxes R and G thus collimated pass through the incident side polarizing plates 960R and 960G, enter the liquid crystal light valves 925R and 925G, are modulated, and image information corresponding to each color light is modulated. Will be added. That is, the switching of these liquid crystal light valves is controlled by driving means (not shown) according to the image information, whereby each color light passing therethrough is modulated. As such a driving means, a known means can be used as it is. On the other hand, the blue light flux B is guided to the corresponding liquid crystal light valve 925B via the light guide system 927, where it is similarly modulated according to image information. In addition, as the liquid crystal light valves 925R, 925G, and 925B of this example, for example, those using a polysilicon TFT as a switching element can be adopted.

The light guide system 927 is a light emitting section 94 for the blue light flux B.
6, a condenser lens 954 disposed on the exit side of the light-receiving element 6, an incident-side reflection mirror 971, an exit-side reflection mirror 972, an intermediate lens 973 disposed between these reflection mirrors, and disposed on the front side of the liquid crystal light valve 925B. Condensing lens 95
The blue light flux B emitted from the condenser lens 953 passes through the incident-side polarizing plate 960B, enters the liquid crystal light valve 925B, and is modulated. The length of the optical path of each color light beam, that is, the distance from the light source lamp 81 to each liquid crystal panel is the longest for the blue light beam B, and therefore, the light amount loss of this light beam is the largest. However, by interposing the light guide system 927, the light amount loss can be suppressed.

Next, each liquid crystal light valve 925R, 92
R, G, and B light beams modulated through 5G and 925B, respectively.
Are incident on the prism unit 910 through the exit-side polarizing plates 961R, 961G, and 961B, and are synthesized there. The color image synthesized by the prism unit 910 is enlarged and projected on the projection surface 100 at a predetermined position via the projection lens 6.

(3) Configuration of Circuit Board As shown in FIG. 1, a circuit board for electrically controlling the light source lamp 81 and the optical unit 10 includes a control circuit 31, a lamp drive circuit 32, an image signal processing circuit, and the like. 33,
And a modulation element drive circuit 34.

The control circuit 31 includes a lamp drive circuit 32 and an image signal processing circuit 33 based on signal outputs from the object detection means 50, a power switch (not shown), an image adjustment button, and the like.
To output a control signal to the object detecting means 5
0 is also configured to be able to exchange signals with the sensor drive processing circuit 54.

The lamp driving circuit 32 is a circuit for turning on / off the light source lamp 81, adjusting the brightness, and the like. The image signal processing circuit 33 is a circuit that outputs a video signal input from an RGB input terminal and a video input terminal (not shown) to the modulation element driving circuit 34 according to a control signal of the control circuit 31. The modulation element driving circuit 34 is a circuit that drives the liquid crystal light valves 925R, 925G, and 925B constituting the light modulation system 925 based on the video signal input from the image signal processing circuit 33. It should be noted that known circuits suitable for controlling the light source lamp 81 and the optical unit 10 are employed as these circuits.

(4) Configurations of Object Detecting Means 50 and Detection Start Determination Means 60 Configurations of Transmitting Element 51 and Receiving Element 52 In FIG. 1, the object detecting means 50 includes a transmitting element 51 and a receiving element 52. And a sensor drive processing circuit 54 for driving the transmitting element 51 and the receiving element 52 of the ultrasonic sensor 53. The transmitting element 51 is an element for transmitting an ultrasonic signal, the receiving element 52 is an element for receiving a reflected wave of the ultrasonic signal transmitted from the transmitting element 51, and these elements 51 and 52 are similar to each other. It has a configuration. In particular,
The transmitting element 51 and the receiving element 52 are a bimorph vibrator in which a piezoelectric ceramic and a metal plate are bonded,
And a funnel-shaped resonator provided at the center of the bimorph vibrator. When a voltage is applied to the piezoelectric ceramic in an element having such a configuration,
Since a mechanical vibration corresponding to the voltage and the frequency is generated, the ultrasonic wave can be radiated into the air via the resonator and can be used as the transmitting element 51. On the other hand, when the piezoelectric ceramics receives an ultrasonic wave and vibrates, an electric charge is generated. Therefore, the ultrasonic wave detected via the resonator can be converted into an electric signal, and can be used as the receiving element 52.

The ultrasonic sensor 53 is provided on the front side of the outer case 2, that is, adjacent to the projection lens 6. The transmitting element 51 is provided so as to be immersed about 6 cm from the front side surface of the outer case 2, and the receiving element 52 is provided.
Are provided flush with the front side surface. Further, a conical tapered portion whose diameter is reduced toward the back is formed near the front side opening of the immersed portion, and the wide angle of the tapered portion is set according to the detection range of the ultrasonic sensor 53. Is done. Specifically, as shown in FIG. 1, the detection range of the transmitting element 51 is set so as to cover substantially the entire projection area A of the projection image by the projection lens 6 in FIG.

Configuration of Sensor Drive Processing Circuit 54 The sensor drive processing circuit 54 is a circuit that controls the output of an ultrasonic signal from the transmitting element 51 and converts an electric signal input from the receiving element 52. The sensor drive processing circuit 54 has a different structure depending on the detection method of the ultrasonic sensor 53, and the object detection means 50 according to the first embodiment
In this case, the ultrasonic sensor 53 employs a pulse reflection time detection method.

In the pulse reflection time detection method, as shown in the graph of FIG. 3, the pulse signal S1 is output intermittently at a predetermined time T from the transmitting element 51, and the pulse signal S1 hits the object. Element 5 for receiving the reflected wave R1
2 and a method of detecting a time difference t between transmission and reception.
Therefore, in order to transmit the pulse signal S1 from the transmitting element 51 every time T and to detect the transmission / reception time difference t when the receiving element 52 receives the reflected wave R1, the sensor drive processing circuit 54 is provided with a timer circuit ( (Not shown in FIG. 1). In this timer circuit, the transmission time interval T of the pulse signal S1 can be changed by the control circuit 31, and the transmission time interval T is set according to the threshold value of retinal damage to the eye due to the thermal action of the light beam emitted from the projection lens. In the case of this example, it is set to 3 seconds.

Structure of Detection Start Determining Unit 60 The projection display apparatus 1 is provided with a detection start determining unit 60 for determining the start of the object detection by the above-described object detecting unit 50. When the operator of the projection display device 1 adjusts the zoom and focus of the projection lens 6, the detection start determination unit 60 detects the object detection unit 5.
0 is not operated, and a known circuit for detecting the adjustment state of the projection lens 6 is provided. Then, upon detecting that the zoom and focus adjustments by the operator have been completed, the detection start determination means 60 outputs a control signal to start detection to the object detection means 50.

(5) Configuration of Projected Image Control Means 70 The projected image control means 70, when a warning signal indicating that the object P has been detected in the projection area A in FIG. 100, a signal switching circuit 71 and a control state display circuit 7
2 is provided.

The signal switching circuit 71 includes the image signal processing circuit 3
A well-known circuit for switching the image signal input to 3 is adopted, and is configured to output an image control signal to the image signal processing circuit 33 in response to a warning signal from the object detection means 50. Specifically, the object detection unit 50 determines that the projection area A
When the object P is detected as having entered the inside, and a warning signal to that effect is input from the object detection means 50 to the signal switching circuit 71,
The signal switching circuit 71 outputs an image control signal for displaying a black image to the image signal processing circuit 33 and the control state display circuit 7.
Output to 2. In response to the input of the image control signal, the control state display circuit 72 recognizes that the projected image is being controlled because the object has entered the projection area A, and displays on the projection screen that “an object has entered the current projection area and Therefore, a message display signal for causing the image signal processing circuit 33 to display a message “The projection image is being controlled.” The image signal processing circuit 33 switches a normal image signal input from an input terminal such as a video terminal or an RGB terminal to a black image based on the image control signal and displays the black image. The message blinks in the upper right corner. Further, the control state display circuit 72
Is an LE provided on the outer case 2 of the projection display device 1.
By outputting a control signal to the D indicator and blinking the LED indicator, it is known that the projected image is in the control state.

(6) Operation of Projection Display Apparatus 1 Next, the operation of the projection display apparatus 1 including the above-described object detection means 50 and projection image control means 70 will be described with reference to the block diagram of FIG. 1 and the flowchart of FIG. It will be described based on the following.

When the power switch is turned on and the projection display apparatus 1 is started, the detection of an object in the projection area by the object detection means 50 is started (STEP 1). When the operator touches the projection lens 6 to adjust the zoom and focus of the projection lens 6, the detection start determination means 60 determines that the screen of the projection display 1 is set (STE).
P2) Output a control signal to control object detection by the object detection means 50 (STEP 3).

When the operator zooms the projection lens 6,
When the hand is released from the focus adjustment portion, the detection start determining means 60 determines that the screen setting by the operator has been completed (STEP 4), and outputs a control signal for canceling the control state of the object detecting means 50. , Object detection means 5
0 returns to the object detection state (STEP 5).

The transmitting element 51 of the object detecting means 50
Is the transmission time interval T (3 in this example) in the graph of FIG.
(Seconds) to transmit an ultrasonic signal S1 to scan the projection area A (STEP 6). During this time, the receiving element 52 receives the reflected wave R1 of the ultrasonic signal S1 and
Detects the transmission / reception time difference t. If the transmission / reception time difference t is detected as a constant value, the sensor drive processing circuit 5
4 determines that the reflected wave R1 is from the projection surface 100 and that no object has entered the projection area A.

When it is detected that a change has occurred in the transmission / reception time difference t, that is, when it is detected that the time difference t has decreased, the sensor drive processing circuit 54 sets the projection area A
It is determined that the object P has entered the inside (STEP 7), and a warning signal to that effect is output to the projection image control means 70.

The signal switching circuit 71 constituting the projection image control means 70 converts a control signal for switching a normal image signal to an image control signal composed of a black image based on the warning signal to the image signal processing circuit 33. Output to Further, the control state display circuit 72 outputs a message display signal to the image signal processing circuit 33, and further outputs a control signal for blinking display to the LED indicator (STE).
P8).

The image signal processing circuit 33 is based on control signals from the signal switching circuit 71 and the control state display circuit 72, and replaces a video signal input from a video input terminal or the like with a video signal composed of a black screen. Is output to the modulation element drive circuit 34. The modulation element drive circuit 34 modulates the liquid crystal light valves 925R, 925G, 925B based on the image control signal and the message display signal. As a result, a black projection image is displayed on the projection surface 100 (STEP 9). At the upper right of the projection screen, "The projection image is currently being controlled because an object has entered the projection area." Is displayed (STE
P10).

When there is no more object P in the projection area A (STEP 11), the transmission / reception time difference t returns to the original state, and the sensor drive processing circuit 54 that has detected this returns the signal to that effect to the signal switching circuit 71 and the control unit. Status display circuit 72
Output to The signal switching circuit 71 and the control state display circuit 72 output a control signal to the image signal processing circuit 33 based on the signal, and transmit a video signal from the video input terminal to the modulation element driving circuit 34 based on the control signal. Output,
The projection image is restored (STEP 12). Further, the control circuit 31 outputs a control signal for canceling the blinking state of the LED indicator, and returns the LED indicator to the display of the standard state (STEP 13).

The scanning of the projection area A by the object detection means 50 as described above is continued until the power supply of the projection display device 1 is shut off (STEP 14).

(7) Effects of the First Embodiment According to the above-described first embodiment, the following effects can be obtained.

That is, since the projection image control unit 70 includes the signal switching circuit 71, when a warning signal indicating that an object has entered the projection area A is input from the object detection unit 50, the projection image Is immediately switched to a black screen, which darkens the display on the projection surface. Therefore, it is possible to provide a simple signal switching circuit to the image signal processing circuit 33 that processes an image signal input from a video terminal or the like without providing a dedicated member for controlling a projected image such as a shutter and a shutter driving circuit. The projection image control means 70 can be configured, and the structure inside the apparatus is not complicated. Further, since the normal projection image is switched to the black image by the signal switching circuit 71, the temperature inside the apparatus does not rise due to the heating of the shutter unlike the conventional projection image control means. Further, since the projected image is switched by the signal switching circuit 71, the switching between the projected image and the black image can be easily and quickly performed.
Even after the projection image is controlled by 0, it is possible to quickly return to the normal projection image.

Further, since the projection display apparatus 1 includes the control state display circuit 72, the state in which the projection image control means 70 is being executed is confirmed, and failure of other parts of the projection display apparatus 1 or the like is confirmed. Discrimination with the control of the accompanying projection image can be easily performed. In particular, in the case of this example, since the control state display circuit 72 displays a message indicating that the control state is on the screen, the control state of the projection image control means 70 can be easily grasped, and the projection type LED of display device 1
Since the indicator is displayed blinking, it is possible to more easily confirm the control state.

Further, since the object detecting means 50 includes the ultrasonic sensor 53, the object can be detected over a wide range in the projection area A by one ultrasonic sensor 53. Further, since the sensor drive processing circuit 54 employs the pulse reflection time detection method, when the object P enters the projection area A, the time difference t changes clearly, and the object detection can be performed with high accuracy. it can.

(8) Configuration and Effect of Projection Display Device According to Second Embodiment Next, a projection display device according to a second embodiment of the present invention will be described. In the following description, the description of the same or similar members or parts as those already described will be omitted or simplified.

In the projection type display device 1 according to the first embodiment, the projection image control means 70 includes a signal switching circuit 71, and the control signal of the signal switching circuit 71
By switching the normal image signal output from the image signal processing circuit 33 to an image control signal for displaying a predetermined image such as a black image, the projected image is darkened.

On the other hand, as shown in FIG. 5, in the projection display device 201 according to the second embodiment, the projection image control means 270 includes a lamp luminance changing circuit 271 for lowering the luminance of the light source lamp 81. Is different.

In the projection display device 1 according to the first embodiment, the object detecting means 50 is configured to include the ultrasonic sensor 53 having the transmitting element 51 and the receiving element 52. On the other hand, the projection display device 201 according to the second embodiment is different in that the object detection means 250 includes two infrared sensors 253 for distance measurement.

The object detecting means 250 includes an infrared sensor 253 for distance measurement and a sensor drive processing circuit 54.
When the infrared sensor 253 detects that an object has entered the projection area A, a warning signal to that effect is output from the sensor drive processing circuit 54. The infrared sensor 253 includes a light emitting unit and a light receiving unit, and is provided on a front side surface of the outer case 2 and is arranged on both sides of the projection lens 6 as shown in FIG. The light emitting section of the infrared sensor 253 is configured to emit infrared rays along the vicinity of the outer periphery of the light beam in accordance with the spread of the light beam in the projection area A. In such an infrared sensor 253, when an object attempts to enter the projection area A, the light receiving section of the infrared sensor 253 detects that the object has entered near the outer periphery of the projection area A, and a warning is issued from the sensor drive processing circuit 54. A signal is output.

The lamp luminance changing circuit 271 is composed of a known circuit that outputs a control signal for lowering the luminance of the light source lamp 81 to the lamp driving circuit 32 in response to a warning signal from the object detecting means 250. Lamp drive circuit 32
Reduces the luminance of the light source lamp 81 based on the control signal from the lamp luminance changing circuit 271. In particular,
An impedance element that can be switched by a switching element or the like is interposed between the light source lamp 81 and a power supply unit (not shown) that supplies power to the light source lamp 81, and the connection state of the impedance element is changed by the control signal. Thereby, the brightness of the light source lamp 81 can be changed. On the other hand, when the infrared sensor 253 of the object detecting means 250 detects that the object has been removed, a signal to that effect is output from the sensor drive processing circuit 54 and the lamp luminance changing circuit 2
71 outputs a control signal to the lamp driving circuit 32, and the lamp driving circuit 32 outputs a light source lamp 81 based on this signal.
Is restored to the original state.

The other parts are the same as in the first embodiment, and the description thereof will be omitted.

According to the second embodiment, the following effects are obtained in addition to the effects described in the first embodiment.

That is, since the projection image control means 270 includes the lamp luminance changing circuit 271, when the object detection means 250 detects that a person or the like has entered the projection area A of the projection image, the luminance of the light source lamp 81 is reduced. It is possible to prevent the intense light flux from acting on the eyes of a person who has lowered the light and entered the projection area.

Further, since the projection image control means 270 only changes the luminance of the light source lamp 81, the object detection means 25
If 0 detects that the intruding object has disappeared, the brightness of the light source lamp can be immediately restored to an appropriate value.

Further, since only the lamp brightness is changed by the operation of the projection image control means 270, a viewer who views the projection image can view the projection image as it is even if an object enters the projection area A.

(9) Modifications of Embodiment The present invention is not limited to the above-described embodiments, but includes the following modifications.

In the first embodiment, the signal switching circuit 71 is configured to output an image control signal for displaying a projected image to a black image to the image signal processing circuit 33; however, the present invention is not limited to this. . That is, the signal switching circuit
The image signal processing circuit may be configured to output an image control signal for displaying a gray screen. The image signal input from an RGB terminal or the like may be image-processed to darken a projected image. It may be configured to output a simple image control signal. In the case where the projected image is displayed dark, the signal switching circuit may be configured to output an image control signal that makes the signal amplitude of the input signal smaller than the original signal to the image signal processing circuit.

In the first embodiment, the ultrasonic sensor 53 performs the object detection by the pulse reflection time detection method, but the present invention is not limited to this. That is, by changing the structure of the sensor drive processing circuit 54 constituting the object detection means 50, the ultrasonic sensor 53 can be of a continuous signal level detection type or a Doppler effect detection type. Here, the continuous signal level detection method is a method of continuously outputting a signal from a transmitting element, receiving the signal continuously by a receiving element, and detecting a change in the signal level of the signal. In addition, the Doppler effect utilization detection method is a method in which a signal continuously output from a transmitting element is received by a receiving element and a change in the frequency of this signal is detected, and when an object approaches or moves away. And that the reflected wave of the ultrasonic wave is modulated by the Doppler effect. If the ultrasonic sensor 53 is a sensor of such a detection system, since the signal is continuously output from the transmitting element, the object can be always detected while the projection image is displayed. .

In the first embodiment, the object detecting means 50 is configured to include the ultrasonic sensor 53, but the present invention is not limited to this. That is, the object detecting means may include a pyroelectric infrared sensor for detecting a human body temperature. If such a pyroelectric infrared sensor is adopted,
Since the pyroelectric infrared sensor detects the temperature of the human body, even if an object other than the human body enters, the projection image control means does not operate, and the control of the projection image by the projection image control means is minimized. can do.

In the first embodiment, the detection start determination means 60 is an adjustment part interlocking type that automatically controls the object detection by the object detection means 50 when the operator touches an adjustment part such as zoom and focus. Although configured as the determination means, it is not limited to this. That is, the detection start determining means is a timer type determining means for controlling the object detection by the object detecting means for a predetermined time set by the operator when the power of the projection type display device is turned on, and the operation of the projection type display device. And an operation start switch for controlling the object detection by the object detection means after the operator confirms the safety state. Further, the object detection start determination means may be configured to include a detection determination function operation switch exclusively set by the operator to start / stop the operation of the object detection means each time.

In the first embodiment, the object detection unit 50 is provided integrally with the projection display device 1.
Not limited to this. That is, the object detection means and the detection start determination means may be prepared as accessories, and may be configured such that they can be connected to a control circuit for controlling the projection display device by a cable as necessary.

In the second embodiment, the object detecting means 250 is configured to include the infrared sensors 253 arranged on both sides of the projection lens 6, but the present invention is not limited to this. That is, the infrared sensor for distance measurement may be provided not only near the outer periphery of the projection area but also inside the projection area. Specifically, if a plurality of infrared sensors are arranged in a fan shape in accordance with the spread of the light beam in the projection area, an object can be detected over a wide range near the outer periphery and inside the projection area. Therefore, even if a person or the like enters the projection area and stays there, a person can be detected by any of the infrared sensors that scan the inside of the projection area, and the object detection can be performed with high accuracy.

In addition, specific structures, shapes, and the like when the present invention is implemented may be other structures and the like as long as the object of the present invention can be achieved.

[0072]

According to the present invention as described above, since the projection image control means of the projection display device includes a signal switching circuit or a lamp luminance changing circuit, the internal structure of the device is complicated. It is possible to control the projection image without inviting, and to immediately return after controlling the projection image.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a projection display device according to a first embodiment of the invention.

FIG. 2 is a schematic diagram for explaining a structure of an optical system according to the embodiment.

FIG. 3 is a graph showing temporal timing of a transmission signal by a transmission element and a reception signal by a reception element of the ultrasonic sensor of the embodiment.

FIG. 4 is a flowchart illustrating an operation of the projection display apparatus according to the embodiment.

FIG. 5 is a block diagram illustrating a projection display device according to a second embodiment of the present invention.

FIG. 6 is a partial front view showing an arrangement of an infrared sensor constituting the object detecting means of the embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 201 Projection display apparatus 6 Projection lens 10 Optical system 50 Object detection means 70 Projection image control means 71 Signal switching circuit 72 Control state display circuit 81 Light source lamp 271 Lamp brightness change circuit A Projection area

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Claims (4)

[Claims] An optical system for optically processing a light beam emitted from a light source lamp to form an optical image according to image information, and a projection lens for enlarging and projecting the optical image on a projection surface. A projection display device comprising: an object detection unit provided to face the projection surface; and a projection image for controlling a projection image displayed on the projection surface according to an output of the object detection unit. Control means, and when a signal indicating that an object is detected is input from the object detection means, the projection image control means displays an image signal constituting the image information to display a predetermined image. And a signal switching circuit for switching to the image control signal. 2. The projection display device according to claim 1, wherein said projection image control means, when said object detection means detects that an object has entered a projection area of said projection image, notifies the fact. A projection type display device comprising a control state display circuit for displaying. 3. A light source lamp, an optical system for optically processing a light beam emitted from the light source lamp to form an optical image in accordance with image information, and a projection lens for enlarging and projecting the optical image on a projection surface. A projection display device comprising: an object detection unit provided to face the projection surface; and a projection image for controlling a projection image displayed on the projection surface according to an output of the object detection unit. Control means, and wherein the projection image control means is configured to include a lamp luminance changing circuit that reduces the luminance of the light source lamp when a signal indicating that an object is detected is input from the object detection means. Projection type display device characterized by the above-mentioned. 4. The projection display apparatus according to claim 3, wherein the projection image control means, when the object detection means detects that an object has entered the projection area of the projection image, notifies that fact. A projection type display device comprising a control state display circuit for displaying.