JP4867148B2 - Projection apparatus, projection control method, and program - Google Patents

Description

  The present invention relates to a projection apparatus using a high-pressure mercury lamp or the like as a light source, a projection control method, and a program.

Conventionally, in a projector generally called a liquid crystal projector using a liquid crystal panel that projects and displays an input image, when a person enters the path of the projection light, it is detected and the emitted light flux of the projection light is suppressed. Therefore, a technique was devised to prevent the dazzling thoughts by irradiating the entering person with high-intensity projection light. (For example, Patent Document 1)
This is because a lamp that emits light with high brightness, such as a high-pressure mercury lamp used as a light source, shortens its life remarkably if it is repeatedly turned on / off in a short time due to physical characteristics, and an expensive lamp can be used in a short cycle. The response speed is higher when the luminous flux of the projection light is suppressed depending on the display content of the liquid crystal panel than turning off the lamp of the light source and the point that it must be replaced, which is an economic burden on the user From the point of view, it is considered an effective technology.
JP 2001-305650 A

  However, although the technique of Patent Document 1 described above suppresses the luminous flux emitted from the liquid crystal panel that forms the optical image, it prevents the person entering the path of the projection light from being dazzled, Then, the same projection operation as in normal projection is continued, and the inside of the apparatus including the liquid crystal panel is heated by the amount of the suppressed light flux.

  For this reason, if the state in which the emitted light beam is suppressed continues, the inside of the apparatus of the projector is abnormally heated, and the inside of the apparatus such as a light source lamp or a liquid crystal panel may be significantly damaged.

  The present invention has been made in view of the above circumstances, and its purpose is to block immediate projection in response to an obstacle that blocks projection in front of the apparatus. Another object of the present invention is to provide a projection apparatus, a projection control method, and a program capable of preventing damage to each part by preventing heating inside the apparatus.

According to a first aspect of the present invention, there is provided a light source lamp, a projection unit including an optical lens that forms and emits an optical image from light projected from the light source lamp, and a cooling fan that blows and cools the light source lamp. Detecting means for detecting when an obstacle approaches within a predetermined distance from the projection means, and blocking the light image emitted from the optical lens when the proximity of the obstacle is detected by the detecting means. And a shutoff control means for increasing the rotational speed of the cooling fan.

According to a second aspect of the present invention, in the first aspect of the invention, the blocking control unit projects a black or similar dark color light image instead of the light image to be originally projected by the projection unit. Features.

According to a third aspect of the present invention, in the first aspect of the present invention, the blocking control means uses a shutter mechanism disposed on an optical path axis from the light source lamp to the optical lens.

According to a fourth aspect of the present invention, in the first aspect of the invention, the projection unit further includes a distance measuring unit that measures a distance to the projection target, and the detection unit is a distance measuring unit of the distance measuring unit. It is characterized in that the proximity of an obstacle is detected from the result.

The invention according to claim 5 is the invention according to claim 4 , wherein the detection means is a predetermined distance that serves as a detection reference for proximity of an obstacle according to the distance to the projection target obtained by the distance measurement means. The value is variably set.

The invention described in claim 6 is the invention described in claim 1 , further comprising a time measuring means for measuring the time after the proximity of the obstacle is detected by the detecting means, and the shut-off control means comprises the detection The light source emitted from the optical lens by detecting the proximity of the obstacle by the means, and after increasing the rotation speed of the cooling fan, the light source at the time when the time value of the time measuring means becomes a constant value The lamp is turned off.

A seventh aspect of the invention is characterized in that, in the sixth aspect of the invention, a constant value which is measured by the timing means until the light source lamp is extinguished can be arbitrarily set.

The invention according to claim 8 is the invention according to claim 6 , wherein the timing means further measures the time after the light source lamp is turned off, and the shut-off control means turns off the light source lamp. The rotation of the cooling fan is stopped when the time value of the time measuring means reaches a constant value.

According to a ninth aspect of the present invention, there is provided a projection apparatus comprising: a projection unit including an optical lens that forms and emits a light image by light projection from a light source lamp; and a cooling fan that blows and cools the light source lamp. And a detection step of detecting an obstacle when it approaches within a predetermined distance from the projection unit, and an emission from the optical lens when the proximity of the obstacle is detected in this detection step. And a blocking control step of blocking the light image to be increased and increasing the rotational speed of the cooling fan.

According to a tenth aspect of the present invention, there is provided a projection apparatus comprising: a projection unit including an optical lens that forms and emits a light image by light projection from a light source lamp; and a cooling fan that blows and cools the light source lamp. Is a program to be executed by a computer built in, and a detection step for detecting when an obstacle comes within a predetermined distance from the projection unit, and a detection step for detecting the proximity of the obstacle in this detection step. The computer executes a blocking control step of blocking a light image emitted from the optical lens and increasing the rotation speed of the cooling fan.

According to the first aspect of the present invention, since the obstacle is detected in the projection direction and at the same time the projection of the image is interrupted, and the rotation speed of the cooling fan is increased to cool the light source lamp, the user and other safety It is possible to reliably avoid an abnormally high temperature inside the apparatus due to heat generated by the light source lamp.

According to the invention described in claim 2 , in addition to the effect of the invention described in claim 1 , the projection is interrupted by projecting a black or similar dark light image instead of the light image to be originally projected. As a result, high-speed response is possible by the electronic circuit of the image projection system.

According to the third aspect of the invention, in addition to the effect of the first aspect of the invention, since the projection is interrupted by the mechanical shutter mechanism, a high-speed response by the mechanism of the image projection system is possible. .

According to the invention described in claim 4 , in addition to the effect of the invention described in claim 1 above, by using a distance measuring mechanism for automatic focusing of the projected image and automatic keystone correction, other obstacle detection can be performed. Therefore, the device configuration can be simplified without requiring a special configuration.

According to the invention described in claim 5 , in addition to the effect of the invention described in claim 4 above, since the detection reference of the proximity of the obstacle is variably set according to the distance projected at that time, it is more realistic. Realistic and accurate obstacle detection can be realized.

According to the sixth aspect of the invention, in addition to the effect of the first aspect of the invention, the proximity of an obstacle is detected to block the light image emitted from the optical lens, and the rotational speed of the cooling fan is increased. After that, the light source lamp is turned off after a certain period of time, so if the projection display is not necessary so that the proximity of the obstacle is maintained to some extent, the light source lamp is turned off and the influence of the heat generation is fundamentally affected. Can be excluded from.

According to the invention described in claim 7 , in addition to the effect of the invention described in claim 1 or 6, it is possible to arbitrarily set the time until the light source lamp is turned off. Can be improved.

According to the invention described in claim 8 , in addition to the effect of the invention described in claim 1 or 6 , the cooling fan is stopped when the light source lamp is further turned off and a predetermined time has elapsed. It is possible to avoid unnecessary power consumption and reduce noise caused by the cooling fan.

According to the ninth aspect of the present invention, since the obstacle is detected in the projection direction and at the same time the projection of the image is interrupted and the rotation speed of the cooling fan is increased to cool the light source lamp, the user and other safety It is possible to reliably avoid an abnormally high temperature inside the apparatus due to heat generated by the light source lamp.

According to the tenth aspect of the present invention, the obstacle is detected in the projection direction and the projection of the image is interrupted at the same time, and the rotation speed of the cooling fan is increased to further cool the light source lamp. It is possible to reliably avoid an abnormally high temperature inside the apparatus due to heat generated by the light source lamp.

  Hereinafter, an embodiment in which the present invention is applied to a projector apparatus will be described with reference to the drawings.

FIG. 1 shows the external configuration of the projector apparatus 10 according to the embodiment, and mainly shows the configuration of the front and top surfaces of the housing. As shown in the figure, a part of the front surface of a rectangular parallelepiped main body casing 11, a projection lens 12 on the right side, and a one-dimensional PSD (Position Sensitive Detector: semiconductor position detecting element) centering on the projection lens 12 are used. Three pairs of distance sensors 13a to 13c were buried. An Ir receiver 14 is disposed on the front and left end sides of the main casing 11.
The projection lens 12 is for projecting a light image formed by a spatial light modulation element such as a micromirror element, which will be described later, onto an object such as a screen, and here, a focus position and a zoom position (projection angle of view). Is arbitrarily variable.

  The distance sensors 13a to 13c each measure the distance to the projection direction along the optical axis parallel to the projection optical axis of the projection lens 12 based on the principle of triangulation, and the projection lens 12 is the center. Two pairs of distance sensors 13a and 13b are arranged in the horizontal direction, and two pairs of distance sensors 13a and 13c (13a are overlapped) are arranged in the vertical direction. It is possible to detect the inclination with respect to the projection optical axis.

  The Ir receiver 14 receives an infrared light (Ir) signal on which a key operation signal from a remote controller of the projector device 10 (not shown) is superimposed.

A switch unit 15 and a speaker 16 are disposed on the upper surface of the main body casing 11.
The switch unit 15 includes various key switches for instructing power on / off of the apparatus, input switching, automatic focusing, automatic keystone correction, and the like.

  The speaker 16 emits a sound of the input audio signal and a beep sound during operation.

Although not shown, an input / output connector section, an Ir receiving section similar to the Ir receiving section 14 and an AC adapter connecting section are disposed on the back surface of the main casing 11.
The input / output connector unit includes, for example, a USB terminal for connection to an external device such as a personal computer, a mini D-SUB terminal for video input, an S terminal, an RCA terminal, a stereo mini terminal for audio input, and the like. .

  The AC adapter connection unit connects a cable from an AC adapter (not shown) serving as a power source.

Next, a detailed configuration of the projection optical system will be described with reference to FIG.
The projector device 10 uses a micromirror element 21 which is one of reflective display elements as a spatial light modulation element that forms a light image. First, the light emitted from the light source lamp 23, which is a high-pressure mercury lamp disposed in the reflector 22, is integrated as, for example, R, G, or B primary color light via a color wheel 25 that is rotationally driven by a motor 24 at a constant speed. 26 is incident.

  A light source system lens 27 configured by combining a plurality of light source lenses in order to reduce lens aberration is disposed on the output side of the integrator 26, and the primary color light emitted from the integrator 26 is the light source system lens. Then, the light is totally reflected by the mirror 28 and enters the micromirror element 21.

  Thus, the primary color light image formed by reflecting the primary color light on the micromirror element 21 is formed by a plurality of lens groups having a zoom function and a focusing function via the mechanical shutter 29. The light is emitted from the projection lens 12 and projected and displayed on a screen (not shown).

  The mechanical shutter 29 is normally opened during a normal projection operation, and is immediately closed when an obstacle crosses a projection direction to be described later, thereby blocking the projected image.

  As shown in the figure, the distance measuring optical axes DA1 to DA3 of the distance sensors 13a to 13c are parallel to the projection optical axis PA of the projection lens 12.

  To be precise, the distance sensor 13a (13b, 13c) measures the distance to the object by measuring the position of the reflected light on the light receiving element based on the principle of triangulation by infrared projection. The LED which projects the light and the PSD which is the light receiving element are each composed of a unit formed adjacent to the optical lens directed in the distance measuring direction.

Next, the functional configuration of the electronic circuit of the projector apparatus 10 will be described with reference to FIG.
In the figure, image signals of various standards input from the input / output connector unit 31 are unified into image signals of a predetermined format by the image conversion unit 33 via the input / output interface (I / F) 32 and the system bus SB. Later, it is sent to the projection encoder 34.

  The projection encoder 34 develops and stores the transmitted image signal in the video RAM 35, generates a video signal from the stored contents of the video RAM 35, and outputs the video signal to the projection drive unit 36.

  This projection drive unit 36 is a spatial light modulation element (high-speed time-division drive) (multiplying a frame rate, for example, 30 [frames / second] and a gray scale display number) corresponding to the transmitted image signal. The micromirror element 21, which is a SOM), is driven for display. High-luminance white light emitted from the light source lamp 23 disposed in the reflector 22 is transmitted to the micromirror element 21 via the color wheel 25. By appropriately coloring the primary color and irradiating it through the mirror 28, an optical image is formed by the reflected light, and projected and displayed on the screen (not shown) through the mechanical shutter 29 and the projection lens 12.

However, the projection lens 12 is driven by a lens motor (M) 37 to appropriately move the zoom position and the focus position.
The fan motor (M) 39 that rotates and drives the light source lamp 23 and the cooling fan 38 that cools the reflector 22 that forms the light source lamp 23 are both based on the supply voltage value from the light source drive unit 40. Works.

  The control unit 41 controls all the operations of the above circuits. The control unit 41 includes a CPU, a non-volatile memory that stores an operation program executed by the CPU including processing for temporarily stopping a projection operation, which will be described later, and a work memory.

  The control unit 41 is also connected to a time measuring unit 42, an audio processing unit 43, and a distance measurement processing unit 44 via a system bus SB.

  The timer 42 measures control times t1 and t2, which will be described later, under the control of the controller 41.

The sound processing unit 43 includes a sound source circuit such as a PCM sound source, converts the sound data given during the projection operation into an analog signal, drives the speaker 16 to emit a loud sound, or generates a beep sound if necessary.
The distance measurement processing unit 48 drives the distance sensors 13a to 13c and measures the distances of three points to the projection target.

  Each key operation signal in the switch unit 15 is directly input to the control unit 41, and a signal from the Ir receiving unit 45 is also directly input. The Ir receiving unit 45 includes an Ir receiving unit provided on the back side of the Ir receiving unit 14 and the main body casing 11, converts the infrared light reception signal into a code signal, and transmits the code signal to the control unit 41.

Next, the operation of the above embodiment will be described.
FIG. 4 mainly shows the contents of control by the control unit 41 when an operation of projecting an image input from an external device (not shown) connected to the input / output connector unit 19 is performed when the power is turned on.

  During the initial normal operation, the light source driving unit 40 applies a rated voltage, for example, 200 [V] to the light source lamp 23 to drive light emission (step S01), and at the same time, a cooling fan 38 for cooling the light source lamp 23. The lower one of the two rated voltages, for example, 9 [V], is applied to the fan motor 39 that rotates the motor, and is rotated (step S02).

  At this time, the image displayed for projection by the micromirror element 21 is gradation driven based on the contents converted by the image conversion unit 33 for each of the RGB primary color components (step S03).

  Incidentally, each one-pixel mirror element forming the micromirror element 21 can display only a binary image by one ON or OFF operation.

Therefore, when one frame of an image is divided into a plurality of fields by time division driving, for example, when the number of gradation bits of the image signal of each primary color component is 4 bits, one frame is divided into 48 (= 2 ⁴ × 3) fields and each pixel is divided. By controlling the number of on / off times in a time-sharing manner in accordance with the gradation of the primary color component every time, it is possible to display the gradation of an image for one pixel of each primary color component.

  In the process of executing the normal projection operation as described above, it is determined whether or not an obstacle has been detected (step S04). This is a distance measurement process to determine whether at least one of the distance values to the projection target obtained from the distance sensors 13a to 13c at that time is within a preset value, for example, 1 [m]. The determination is made based on the signal from the unit 44. If no obstacle is detected, the process returns to step S01 and the normal projection operation is continued.

  In this way, the processing in steps S01 to S04 is repeated to execute a normal projection operation, and at the same time, waiting for an obstacle to be detected is waited for.

  Thus, for example, when a person crosses in front of the projector device 10 or when an obstacle is detected by the user of the projector device 10 performing settings, this is determined in step S04, and the projection operation is performed. Transition to the pause state.

  Specifically, after the timer 42 is reset and the timing operation is newly started (step S05), all the gradation values for each primary color component of the image displayed for projection by the micromirror element 21 are “ “0 (zero)”, and the micromirror element 21 performs display in which the entire screen is black (step S06).

  In this case, since the light from the light source lamp 23 is totally reflected by the micromirror element 21 to a place other than the optical path to the mechanical shutter 29 and the projection lens 12, the light quantity emitted from the projection lens 12 is “0 (zero)”. Nothing is displayed on the screen or the like to be projected, and even if the obstacle is a human including the user of the projector device 10, there is no dazzling feeling (projection state of a black image).

  By doing so, the light emission of the light source lamp 23 and the display drive of the micromirror element 21 are maintained, and the light emission luminance of the light source lamp 23 decreases when the projection is resumed later, and the display drive by the micromirror element 21 is delayed. It is possible to avoid such a situation.

  However, as described above, the light emitted from the light source lamp 23 is totally reflected by the micromirror element 21 and is irradiated to a fixed position other than the mechanical shutter 29 and the projection lens 12, so that the main body casing of the projector device 10 is kept as it is. 11, more heat will be trapped.

  Accordingly, in addition to the black display on the micromirror element 21, the fan motor 39 that rotates the cooling fan 38 for cooling the light source lamp 23 also has a higher one of the two rated voltages, for example, 15 [V ] Is driven to rotate at a higher speed (step S07).

  In this state, whether or not an obstacle is still detected is determined based on a signal from the distance measurement processing unit 44 based on the same criterion as in step S04 (step S08), and the obstacle is still detected. In this case, it is further determined whether or not the time measured by the time measuring unit 42 that has started time measurement in step S05 has reached a preset first time t1, for example, 60 [seconds] (step S09).

  If it is determined in step 08 that no obstacle has been detected, the process returns to step S01 again, the black image projection state is stopped, and the normal projection operation is resumed.

  On the other hand, if it is determined in step S09 that the time measured by the time measuring unit 42 has not reached the first time t1, the process returns to step S06 to maintain the black image projection state.

  If the state of projecting a black image by detecting the obstacle continues for a certain time, for example, 60 [seconds], this is determined in step S09, and the time measuring unit 42 is reset again to newly start the time measuring operation. (Step S10), the light source lamp 23 is turned off (Step S11), and the fan motor 39 that rotationally drives the cooling fan 38 for cooling the light source lamp 23 is driven by the lower of the two rated voltages. For example, 9 [V] is applied and rotationally driven at the same speed as in a normal projection operation (step S12).

  In this state, whether or not an obstacle is still detected is determined based on a signal from the distance measurement processing unit 44 based on the same criterion as in step S04 (step S13), and the obstacle is still detected. In this case, it is further determined whether or not the time measured by the time measuring unit 42 that has started time measurement in step S10 has reached a preset second time t2, for example, 300 [seconds] (step S14).

  If it is determined in step 13 that no obstacle has been detected, the process returns to step S01 again, the light source lamp 23 is turned off, and the normal projection operation is resumed.

  On the other hand, if it is determined in step S14 that the time measured by the time measuring unit 42 has not reached the second time t2, the light source lamp 23 is turned off to maintain the state where projection is stopped. Return to processing.

  However, if the state where the projection is stopped due to the detection of the obstacle continues for a certain time, for example, 300 [seconds], this is determined in step S14, and the power is automatically turned off to perform all operations. Stop.

  As described above, the light emission by the light source lamp 23 and the display driving of the micromirror element 21 are continued immediately after the first predetermined time t1, for example, 60 [seconds] has elapsed after the obstacle is detected. While maintaining the state in which the original projection state can be restored, the rotational speed of the cooling fan 38 is also increased as compared with the normal projection operation so far so that heat is not trapped in the projector device 10 as much as possible. did.

  Therefore, the light source lamp 23 is not repeatedly turned on / off in a short time, and the deterioration of the expensive light source lamp 23 is prevented, and the inside of the apparatus is reliably heated to an abnormally high temperature due to the heat generated by the light source lamp. This can be avoided and can easily be restored to the original projection operation.

  Further, when the first predetermined time elapses after the obstacle is detected, the light source lamp 23 is turned off and the light source is cooled by the cooling fan 38 until the second predetermined time t2, for example, 300 [seconds] elapses. The light source lamp 23 is cooled by rotating the lamp 23 at the same speed as in the normal projection operation.

  Therefore, until the second predetermined time t2 elapses, useless power consumption due to the lighting drive of the light source lamp 23 is avoided and the cooling fan 38 is sufficiently cooled, and the second predetermined time t2 elapses. Instant power can be automatically turned off at the moment.

  In the above embodiment, all the gradation values for each primary color component are “0 (zero)” by the micromirror element 21 until the first predetermined time elapses after the obstacle is first detected. The projection state of the black image to be set is set, but it is not particularly limited to the “black” image, and the black image such as dark blue is not felt when the obstacle is a human being. An approximate dark color and slightly bright color may be projected and displayed.

  Further, instead of controlling the content of the projected image as described above, the micromirror element 21 performs normal display drive as before, while mechanically blocking the projected light beam by the mechanical shutter 29 in the projection optical path. It is good also as what to do.

  By using the mechanical shutter 29 in this way, a high-speed response in the projection system is possible without changing the processing content in the circuit of the display system of the image data for driving the display of the micromirror element 21.

  Furthermore, in the above-described embodiment, the distance sensors 13a to 13c and the distance measurement processing unit 44 that measure the distance to a plurality of positions to the projection target are originally used in order to perform automatic focusing and automatic keystone correction of the image. Thus, when a distance value within a certain distance value that is considered too close as a projection target is detected, it is detected that there is an obstacle.

  Thereby, it is not necessary to provide a distance measuring mechanism for detecting obstacles in particular, and the apparatus configuration can be simplified.

  In the embodiment, the distance value serving as a reference for obstacle detection is set to 1 [m], for example, but the reference distance value is a projection already obtained by automatic focusing and automatic keystone correction at that time. In conjunction with the distance value to the target, for example, if the distance value is within half of the distance value to the projection target, it may be determined that the object is an obstacle, and may be variably set corresponding to the projection state. By doing so, it is possible to realize more accurate obstacle detection that is more realistic.

  Further, if the first and second predetermined times t1 and t2 associated with the obstacle detection are not fixed values but can be variably set by the user of the projector device 10, the user uses the projector device 10. In accordance with the content of the presentation to be performed, the usability can be further improved, wasteful power consumption can be avoided by the setting method, and noise from the cooling fan can be reduced.

  In this embodiment, a micromirror element is used as an element for forming an optical image. However, the present invention is not limited to this, and other optical images such as those using a transmissive color liquid crystal panel are used. The same can be applied to a projection apparatus using a forming element.

  In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  Further, the above embodiments include inventions at various stages, and various inventions can be extracted by appropriately combining a plurality of disclosed constituent elements. For example, even if some constituent elements are deleted from all the constituent elements shown in the embodiment, at least one of the problems described in the column of the problem to be solved by the invention can be solved, and described in the column of the effect of the invention. In a case where at least one of the obtained effects can be obtained, a configuration in which this configuration requirement is deleted can be extracted as an invention.

1 is a perspective view showing an external configuration of a projector apparatus according to an embodiment of the present invention. The perspective view which extracts and shows the mechanism of the projection system which concerns on the same embodiment. 2 is a block diagram showing a functional configuration of the electronic circuit according to the embodiment. FIG. The flowchart which shows the processing content of the obstacle detection from the time of power-on and the control of a light source concerning the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Projector apparatus, 11 ... Main body casing, 12 ... Projection lens, 13a-13c ... Distance sensor, 14 ... Ir receiving part, 15 ... Switch part, 16 ... Speaker (SP), 21 ... Micromirror element, 22 ... Reflector, DESCRIPTION OF SYMBOLS 23 ... Light source lamp, 24 ... Motor, 25 ... Color wheel, 26 ... Integrator, 27 ... Light source system lens, 28 ... Mirror, 29 ... Mechanical shutter, 31 ... Input / output connector part, 32 ... Input / output interface (I / F) 33 ... Image conversion unit, 34 ... Projection encoder, 35 ... Video RAM, 36 ... Projection drive unit, 37 ... Lens motor (M), 38 ... Cooling fan, 39 ... Fan motor (M), 40 ... Light source drive unit, DESCRIPTION OF SYMBOLS 41 ... Control part, 42 ... Time measuring part, 43 ... Audio | voice processing part, 44 ... Distance measuring process part, PA ... Projection optical axis, DA1-DA3 ... Distance measuring optical axis, B ... system bus.

Claims (10)

A light source lamp,
Projection means including an optical lens that forms and emits an optical image from light projection from the light source lamp,
A cooling fan that blows and cools the light source lamp;
Detecting means for detecting an obstacle when approaching within a predetermined distance from the projection means;
A projection apparatus comprising: a blocking control unit that blocks a light image emitted from the optical lens when the proximity of an obstacle is detected by the detection unit and increases a rotation speed of the cooling fan.   2. The projection apparatus according to claim 1, wherein the blocking control unit projects a black or similar dark light image instead of the light image originally projected by the projection unit.   2. The projection apparatus according to claim 1, wherein the blocking control means uses a shutter mechanism disposed on an optical path axis from the light source lamp to the optical lens. The projection means further includes a distance measurement means for measuring a distance to the projection target,
The projection apparatus according to claim 1, wherein the detection unit detects the proximity of an obstacle from a distance measurement result of the distance measurement unit.   5. The projection apparatus according to claim 4, wherein the detection unit variably sets a predetermined distance value serving as a detection reference for the proximity of an obstacle according to the distance to the projection target obtained by the distance measurement unit. . It further comprises time measuring means for measuring the time since the detection means detects the proximity of the obstacle,
The blocking control means detects the proximity of an obstacle by the detecting means, blocks the light image emitted from the optical lens, increases the rotation speed of the cooling fan, and then keeps the time value of the time measuring means constant. The projection apparatus according to claim 1, wherein the light source lamp is turned off when the value is reached. 7. The projection apparatus according to claim 6, wherein a constant value measured by the time measuring means until the light source lamp is extinguished can be arbitrarily set. The time measuring means further measures the time after the light source lamp is turned off,
The projection apparatus according to claim 6 , wherein the shut-off control unit stops the rotation of the cooling fan at a time point when the time measured by the time measuring unit becomes a constant value after the light source lamp is turned off. A projection control method of a projection apparatus comprising: a projection unit including an optical lens that forms and emits an optical image from light projection from a light source lamp; and a cooling fan that blows and cools the light source lamp,
A detection step of detecting an obstacle when approaching within a predetermined distance from the projection unit;
A projection control method comprising: a blocking control step of blocking a light image emitted from the optical lens and increasing a rotation speed of the cooling fan when proximity of an obstacle is detected in the detection step. A program executed by a computer built in a projection device including a projection unit including an optical lens that forms and emits an optical image from light projection from a light source lamp, and a cooling fan that blows and cools the light source lamp Because
A detection step of detecting an obstacle when approaching within a predetermined distance from the projection unit;
A program for causing a computer to execute a blocking control step of blocking a light image emitted from the optical lens and increasing a rotation speed of the cooling fan when proximity of an obstacle is detected in this detection step.

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