Projection apparatus

Abstract

To prevent the light of a projection device from entering the eyes of a person and dazzling the person when the person enters a projection range or the projection device is moved in the projection device capable of performing projection in an optional direction.SOLUTION: A projection device includes a projection unit that projects image light 204 onto a projection surface 205, a distance detection unit that can measure distances to the projection surface 205 at a plurality of positions, and a luminance adjustment unit that adjusts luminance of the projection unit on the basis of measurement values of the distance detection unit, wherein a measurement range of the distance detection unit is wider than a projection range of the image light 204.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to an anti-dazzle feature for a projection device. [Background technology]

[0002] Conventionally, stationary projection devices that have been sold have extendable legs on the bottom surface of the projection lens side, and by adjusting these legs, the projection angle can be adjusted.

[0003] However, the legs are not designed to be easily adjustable, and there is a limit to the angle of adjustment, so while this is not a problem when used in a fixed location such as a conference room, it is difficult to use in an ordinary home as it provides limited flexibility.

[0004] To solve the above problems, projection devices for general household use have been designed with various ideas, such as providing a tripod screw hole on the bottom so that any tripod can be attached, or making the product shape itself circular so that it can project at any angle.

[0005] As described above, projection devices for general home use are constructed so that projection can be easily performed in any direction. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2015-43010 Summary of the Invention [Problem to be solved by the invention]

[0007] However, since projection devices project images using reflections from walls, extremely strong light is projected from the lens of the projection device, and looking directly at this light can cause visual impairment or blindness.

[0008] Stationary projection devices are often fixed to the ceiling of a conference room, and in such cases, the seats are also set up to face the projection direction, so there is little chance of being dazzled unless one intentionally tries to look directly into the lens.

[0009] However, projection devices for general households are small, can be installed freely, and are not limited to certain users, so there is a risk that a child may look into the lens or be accidentally projected into their eyes when the projection device is turned around, causing dazzling.

[0010] To prevent this, prior art has proposed a technology that uses a distance sensor or camera to measure the distance to the projection surface, and if that distance suddenly changes and falls below a threshold, it is determined that a person has entered the area and the projection brightness is reduced (for example, Patent Document 1).

[0011] However, since it takes some time for the sensor to react and reduce the projection brightness after a person enters the projection range, there is a risk of dazzling the person during that time.

[0012] To prevent this, some prior art technologies set a distance measurement range so that the sensor responds over a wider range than the projection range, but because the sensor can only acquire one distance, if, for example, a desk is placed near the projection range, it is not possible to determine whether the distance acquired by the sensor is for the projection surface, the desk, or a person. [Means for solving the problem]

[0013] In view of the above, a projection device according to the present invention comprises: a projection unit that projects image light onto a projection surface; a distance detection unit capable of measuring distances to the projection surface at a plurality of points; a brightness adjustment unit that adjusts the brightness of the projection unit based on the measurement value of the distance detection unit, The distance detection unit has a measurement range wider than a projection range of the image light. [Effects of the Invention]

[0014] According to the present invention, in a projection device that allows projection in any direction, it is possible to prevent light from the projection device from entering people's eyes and causing dazzle. [Brief explanation of the drawings]

[0015] [Figure 1] 1 illustrates an embodiment of the present invention. [Figure 2] FIG. 1 is a block diagram showing a configuration of the present invention. [Figure 3] FIG. 1 is a diagram illustrating a multi-zone distance measuring sensor. [Figure 4] FIG. 10 is a diagram illustrating a method for detecting a person. [Figure 5] FIG. 10 is a diagram illustrating an example in which the measurement zone is placed outside the projection range. [Figure 6] 10A and 10B are diagrams illustrating a method for preventing dazzle when a person enters the room. [Figure 7] FIG. 10 is a diagram illustrating an example in which an obstacle is present in the measurement zone. [Figure 8] 10A and 10B are diagrams illustrating a method for preventing glare when the projection device is moved. [Figure 9] 10 is a flowchart illustrating a process for increasing the detection speed during rotation. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. As an example, the distance detection unit is a distance measurement sensor 103, and the acceleration detection unit and rotation detection unit are an acceleration sensor 201, but the detection method is not limited thereto.

[0017] FIG. 1 is a diagram illustrating an embodiment of the present invention.

[0018] Reference numeral 100 denotes a projection device. Reference numeral 101 denotes a rotation mechanism, which allows the orientation of the projection device 100 to be changed in the pitch direction (up and down direction) from the ceiling direction to the placement surface direction. The projection device 100 is equipped with a projection lens 102 for projecting light and a distance measurement sensor 103.

[0019] FIG. 2 is a block diagram showing the configuration of the present invention, specifically illustrating the internal configuration of the projection device 100. As shown in FIG.

[0020] The projection device 100 includes a substrate 200. An acceleration sensor 201 and a brightness adjustment unit 202 are mounted on the substrate 200. Data measured by the distance measurement sensor 103 and the acceleration sensor 201 is input to the brightness adjustment unit 202, which adjusts the output brightness of a projection unit 203, which is a projection unit, based on the data. The projection unit 203 projects light of the adjusted brightness from the projection lens 102. The image light 204 projected from the projection lens 102 is projected onto a projection surface 205. Lowering (reducing) the output brightness of the projection unit 203 or stopping projection by the brightness adjustment unit 202 is referred to as adjusting the brightness of the projection unit by the brightness adjustment unit 202.

[0021] The distance measurement sensor 103 provided in the projection device 100 is a multi-zone sensor that can measure distances at multiple locations as a product, and Figure 3 is a diagram illustrating an example of a multi-zone distance measurement sensor with a 2x2 measurement zone.

[0022] 3 has four measurement zones 300, A, B, C, and D, relative to the projection surface 205, and is capable of measuring a measurement distance 301 relative to the projection surface 205 for each of the measurement zones 300, A to D. Because it is possible to measure the distance at multiple points relative to the projection surface 205, it is possible to calculate the inclination of the projection surface 205 relative to the projection device 100 by using each measurement value. By using the calculated inclination value, it is possible to automatically perform keystone correction.

[0023] FIG. 4 illustrates a method for detecting a person using the distance measurement sensor 103 illustrated in FIG.

[0024] 4, when a person 400 enters in front of measurement zone 300 D out of the four measurement zones 300, the measured distance 401 to the person 400 who has entered in front of measurement zone 300 D becomes extremely shorter than the measured distances 301 to the projection surface 205 of the other measurement zones 300 A to C. In this way, when the distance measuring sensor 103 detects that the measured value has become lower (shorter) than the threshold value, it can be determined that a person has entered in front of the projection device 100.

[0025] FIG. 5 is a diagram illustrating an example in which the measurement zone (measurement range) is disposed outside the projection range.

[0026] 5 uses a multi-zone distance measuring sensor with a 5x5 measurement zone. Projection range 500 indicates the range projected by projection unit 203 onto projection surface 205. Measurement zone 300 located outside projection range 500 is indicated as measurement zone 501.

[0027] Although the measurement zone is set to 5×5 in this example, it is not limited thereto and may be, for example, 10×10 or 50×50.

[0028] FIG. 6 is a diagram illustrating a method for preventing dazzle when a person enters the area when the above-mentioned 5×5 measurement zone is used.

[0029] When person 400 approaches projection range 500, person 400 enters measurement zone 501 outside projection range 500, shortening the measurement distance to measurement zone 501, and the measurement distance to measurement zone 501 becomes measurement distance 401 to person 400. This makes it possible to detect that person 400 is approaching projection range 500. At this point, projection unit 203 can reduce the projection brightness or stop projection before person 400 enters projection range 500, making it possible to prevent dazzling of person 400 who has entered.

[0030] However, simply stopping the projection would result in a sudden halt in projection, which would be unhelpful for usability. To prevent this, for example, two-stage glare prevention processing may be performed, such that the projection brightness is reduced when person 400 enters measurement zone 501 outside projection range 500, and projection is stopped when person 400 moves further in (when about to enter projection range 500).

[0031] Furthermore, since there may be cases where a person intentionally enters the projection range 500 during a presentation or the like, the mode of the anti-dazzle function may be switched depending on the orientation of the rotation mechanism 101, such as by using a normal mode that does not prevent dazzle when projecting onto a wall and a safety mode that prevents dazzle when projecting onto a ceiling. The orientation of the rotation mechanism 101 can be detected by using the acceleration sensor 201 mounted on the projection device 100 as a rotation detection unit.

[0032] As described above, the rotation detection unit does not have to be limited to the acceleration sensor 201 as long as it can detect the movement and orientation of the rotation mechanism unit 101, such as the angle and tilt.

[0033] FIG. 7 is a diagram illustrating a case where an obstacle is present in the measurement zone.

[0034] In the prior art, if an obstacle 700 was placed within the measurement zone 300, it was not possible to determine whether the measured distance was the distance to the obstacle 700, the distance to the person 400, or the distance to the projection surface 205.

[0035] By using a multi-zone distance measuring sensor as proposed in this invention, it is possible to measure the distance for each zone, so that the measured distance for obstacle 700 is shown as measured distance 701, the measured distance for person 400 as measured distance 401, and the measured distance for projection surface 205 as measured distance 301, thereby preventing false detection.

[0036] Note that obstacle 700 is an object such as a desk, flowerpot, or box that is originally placed in a room, etc., and is not moving, so the distance does not change during projection. On the other hand, person 400 is a moving object, so the measured distance changes as the person moves in and out of projection range 500 during projection. Therefore, by checking whether there is a change in the measured distance from the initial projection state, it is possible to determine whether the object for which the distance is being measured is obstacle 700 or person 400, and prevent dazzle only for person 400.

[0037] In addition to making the determination based on the change in the measured distance as described above, it is also possible to determine whether the object is a person 400 or an obstacle 700 based on the time during which the distance is measured.

[0038] FIG. 8 is a diagram illustrating a method for preventing dazzle when the projection device 100 is moving.

[0039] Since the projection range 500 moves in accordance with the projection device 100, if the projection device 100 is moved or tilted, there is a risk that the projection will be directed at a person 400 and that the person 400 will enter the projection range 500 as shown in FIG.

[0040] The acceleration sensor 201 mounted on the projection device 100 is used as an acceleration detection unit to determine whether the projection device 100 is moving, and if the projection device 100 is moving, it is determined that the acceleration has exceeded a threshold value, and the projection brightness is reduced, thereby preventing dazzle in advance.

[0041] As mentioned above, the projection brightness is reduced when person 400 enters the projection range 800 or when projection device 100 moves, but this does not limit the glare prevention method, and any method that can prevent glare, such as stopping the projection, will suffice.

[0042] The user can change the projection direction by rotating the rotation mechanism 101 shown in Fig. 1, but because the rotation mechanism 101 can change the projection direction instantaneously compared to when the main body is moved, there is a higher possibility of dazzle when rotating. Therefore, when the rotation mechanism 101 is rotating, it is necessary to prevent dazzle more quickly than usual.

[0043] To achieve the above, a process for suppressing power consumption by increasing the detection speed only while the rotation mechanism 101 is rotating will be described with reference to the flowchart shown in FIG.

[0044] When the projection device 100 starts projection operation, it first starts normal operation (S900). During normal operation (S900), low power mode processing (S902) is performed to suppress the detection speed of the distance measurement sensor 103 and reduce current consumption. At this time, the acceleration sensor 201 provided in the projection device 100 constantly monitors the rotation of the rotation mechanism unit 101, and determines whether the rotation mechanism unit 101 has operated (rotated) through rotation detection processing (S903). If operation (rotation) of the rotation mechanism unit 101 is detected (S903: YES), the projection device 100 transitions to high-speed operation (S901).

[0045] If rotation of the rotation mechanism 101 is not detected (S903: NO), the process remains in the low power mode (S902) in which the detection speed of the distance measurement sensor 103 is reduced during normal operation (S900).

[0046] When the operation of the rotation mechanism unit 101 is detected (S903: YES), the system transitions to high-speed operation mode (S901), where a high-speed detection mode (S904) is executed to increase the detection speed of the distance measurement sensor 103 so that anti-dazzle processing can be performed quickly. After the high-speed detection mode processing (S904) is executed, a determination is made in rotation detection processing as to whether the rotation mechanism unit 101 has stopped (S905). If it is determined that the rotation mechanism unit 101 has stopped (S905: YES), a wait processing (S906) is executed, and the rotation detection processing is executed again to determine whether the rotation mechanism unit 101 has stopped (S907).

[0047] In the rotation detection process, it is determined whether the rotation mechanism 101 has stopped (S905), and if it has not stopped (S905: NO), the detection speed of the distance measuring sensor 103 is kept increased in the high-speed detection mode process.

[0048] After the wait process (S906), the rotation detection process determines whether the rotation mechanism unit 101 has stopped (S907), and if it is determined that rotation has stopped for a certain period of time (S907: YES), it is determined that the rotation mechanism unit 101 is not rotating and is stably placed, and the process returns to normal operation (S900), and the detection speed of the distance measurement sensor 103 is reduced.

[0049] After the wait process (S906), if it is determined that the operation has not stopped (S907: NO), the rotation mechanism unit 101 is considered to be rotating again, and the detection speed of the distance measurement sensor 103 is kept increased while maintaining high-speed operation (S901).

[0050] The above process makes it possible to prevent sudden dazzling when rotating while suppressing current consumption.

[0051] Furthermore, normal operation (S900) and high-speed operation (S901) may be switched depending on the projection direction. When the projection surface is facing forward, such as a wall, normal operation (S900) is performed, but when the projection direction is facing upward, such as a ceiling, there is a possibility of someone looking into the projection from close range, so high-speed operation (S901) is performed as a safety mode to prevent dazzle, as described above.

[0052] Therefore, the rotation direction of the rotation mechanism unit 101 may be determined in steps S903, S905, and S907, and if the projection direction is toward the ceiling or a direction at a certain angle or more, high-speed operation (S901) may be performed.

[0053] Furthermore, instead of switching between normal operation (S900) and high-speed operation (S901) upon detecting the rotation direction or rotational operation of the rotation mechanism unit 101, the operation processing may also be switched upon detecting movement of the projection device 100 itself, as described above.

[0054] As a result, it is possible to provide a product that is excellent in usability while preventing glare. [Explanation of symbols]

[0055] 100 Projection device 101 Rotation mechanism 102 Projection lens 103 Distance Sensor 200 boards 201 Acceleration sensor 202 Brightness adjustment section 203 Projection Unit 204 Image Light 205 Projection surface 300 measurement zones 301 Measurement distance 400 people 401 Measurement distance to a person 500 Projection Range 501 Measurement zone outside the projection range 700 Obstacles 701 Measurement distance to obstacle 700

Claims

1. a projection unit that projects image light onto a projection surface; a distance detection unit capable of measuring distances to the projection surface at a plurality of points; a brightness adjustment unit that adjusts the brightness of the projection unit based on the measurement value of the distance detection unit, A projection device, characterized in that the measurement range of the distance detection unit is wider than the projection range of the image light.

2. 2. The projection device according to claim 1, wherein the brightness adjustment unit adjusts the brightness of the projection unit when the measurement value by the distance detection unit is lower than a threshold value.

3. An acceleration detection unit is provided, 2. The projection device according to claim 1, wherein the brightness adjustment unit adjusts the brightness of the projection unit when a value measured by the acceleration detection unit exceeds a threshold value.

4. A rotation detection unit; a rotation mechanism for changing the projection direction, 2. The projection device according to claim 1, wherein the rotation detection unit detects the rotation of the rotation mechanism unit, and when the rotation of the rotation mechanism unit is detected, the detection speed of the distance detection unit increases.

5. The projection device according to claim 1, wherein the brightness adjustment unit adjusts the brightness for a person within the measurement range of the distance detection unit, but does not adjust the brightness for an obstacle within the measurement range of the distance detection unit.

6. The projection device according to claim 1 , wherein the detection speed of the distance detection unit is changed depending on the projection direction of the projection unit.

7. 2. The projection device according to claim 1, further comprising an acceleration detection unit, and wherein the detection speed of the distance detection unit is switched in accordance with a measurement value of the acceleration detection unit.

Images