JP4019099B2 - Projector with foreign object sensor circuit - Google Patents

Description

  The present invention relates to a projector that includes a projection mirror with an aperture structure and that enlarges and projects display light of an image generated on a video display element onto an external screen, and more particularly, to a projector that has a high-intensity foreign object sensor circuit.

  Projectors for enlarging and projecting display light of an image generated on a video display element onto a screen provided outside are used for various purposes. In recent years, the brightness of projectors has been increased, and the number of bright projectors with a large display light intensity has been increasing. For this reason, the temperature at the projection lens portion of the projector is also very high.

  Recently, a projector having an aperture structure and a projection mirror has been developed. As shown in the schematic side view of FIG. 5, the casing 51 of the projector 50 is provided with an opening 52, and the opening 52 has an opening lens 53 that emits display light. A projection mirror 54 is provided facing the lens 53. In use, the display light 55 of the image generated on the video display element is emitted through the aperture lens 53, reflected by the projection mirror 54, and enlarged and projected on a screen (not shown) provided outside. Note that the light source, the image display element, the optical system, and the like constituting the projector are not shown in the figure. The projection mirror may also be used as a lid for the opening, and the lid may be closed when the projector is not used.

  Conventionally, an aperture projection type projector as shown in FIGS. 6A and 6B has also been developed. That is, the light source 64, the liquid crystal display element 65, the projection mirror 63 that projects the display light modulated by the image generated on the liquid crystal display element 65 onto the external screen, and the light source 64, the liquid crystal display element 65, and the illumination optical system are accommodated. A housing 61, and an opening 62 for emitting display light from the liquid crystal display element 65 to the projection mirror 63 between the liquid crystal display element 65 and the projection mirror 63 of the housing 61. One end of the projection mirror 63 is attached to the outer wall of the housing 61 so as to be able to fall down and pull up. The projection mirror 63 constitutes a projection optical system in the raised state and functions as a lid that closes the opening 62 in the tilted state. (See Patent Document 1).

JP 11-119343 A ([0032] to [0034], FIG. 1)

  In the case of a projector having a projection mirror with such an aperture structure, the portion of the aperture lens that becomes hot is exposed. Furthermore, if foreign matter comes to this part, the display light is blocked and a rapid temperature rise occurs. In the worst case, it may be a burn or a fire, so it is necessary to take countermeasures.

  Also in the aperture projection type projector described in Patent Document 1, when the brightness is increased, the intensity of the display light in the vicinity of the reflection mirror increases and the temperature increases. However, Patent Document 1 does not describe any countermeasures against foreign matters that enter the optical path of the display light.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a projector including a foreign matter sensor circuit that can detect a wide range of small foreign matters efficiently with a simple structure in order to solve the above problems.

  The projector of the present invention is a projector having an image display element, and is based on a housing having an opening, a light emitting unit that emits sensor light, a light receiving unit that receives the sensor light, and a signal from the light receiving unit. A foreign substance detector including a control unit for controlling the projector, wherein display light of an image generated on the video display element passes through the opening, and the sensor light passes through the opening. It is characterized by crossing the optical path. Alternatively, the projector according to the invention is characterized by having a mirror that reflects the sensor light. Alternatively, the projector according to another aspect of the invention includes a plurality of mirrors that reflect the sensor light, and the plurality of mirrors are arranged to face each other so as to sandwich the display light passing through the opening. And Alternatively, in the projector of the invention, at least one of the plurality of mirrors reflects the sensor light twice or more. Alternatively, the projector according to another aspect of the invention includes two mirrors that reflect the sensor light, and the two mirrors are arranged to face each other so as to sandwich the display light passing through the opening. The light is multiple-reflected between the two mirrors. Alternatively, the projector according to the invention has a projection mirror outside the casing, and the display light that has passed through the opening is reflected by the projection mirror. Alternatively, the projector according to the invention is characterized in that the projection mirror is attached to the projector so as to be able to fall and cause, and constitutes a projection optical system in the raised state and closes the opening in the lowered state. .

  Alternatively, the projector of the present invention is characterized in that the sensor light has a peak wavelength in an infrared region. Alternatively, the projector of the invention is characterized in that the control unit turns off the lamp when the signal from the sensor light receiving unit indicates that the sensor light is not detected for a predetermined time. Alternatively, the projector according to the invention is characterized in that the control unit turns on the lamp when the signal from the sensor light receiving unit indicates detection of the sensor light. Alternatively, the projector according to the invention is characterized in that the control unit mutes the video when the signal from the sensor light receiving unit indicates that the sensor light is not detected for a predetermined time. Alternatively, in the projector according to the aspect of the invention, the control unit may mute the video and perform on-screen display when the signal from the sensor light receiving unit indicates that the sensor light is not detected for a predetermined time. It is characterized by. Alternatively, in the projector of the invention, the control unit is characterized in that at least a part of the on-screen display is gray. Alternatively, the projector according to the invention is characterized in that the predetermined time is arbitrary. The feature is the sensor part, which is configured so that the sensor light does not spread, or a sensor with a certain degree of directivity is used, and a mirror is installed between the light emission and light reception of the sensor to reflect and reflect the sensor light. It is the structure which detects interruption | blocking. A pair of sensors makes it possible to easily detect a wide range of small foreign objects with a minimum circuit scale.

  According to the present invention, in a projector that includes a projection mirror with an aperture structure, and that reflects the display light of an image generated by the video display element from the aperture lens by the projection mirror and magnifies and projects it on a screen provided outside, the aperture lens and Since the foreign matter sensor circuit for detecting the invading foreign matter is provided in the display optical path to the projection mirror, the foreign matter can be detected by using only one sensor circuit. It can be realized and is very efficient, and has the feature that the number of parts and current consumption can be reduced and the cost can be reduced. In addition, since a rapid temperature rise due to the entry of foreign matter can be prevented, a safe projector can be provided.

  Even if a foreign object is simply detected by a sensor and a protection circuit is to be added, the number of sensors is increased. The sensor unit normally requires a plurality of sensors to detect foreign substances over a wide range, and the smaller the foreign substance size to be detected, the further the number of sensors increases and the circuit scale increases. According to the present invention, such a problem can be avoided. Furthermore, the foreign substance sensor circuit of the present invention has an effect that the detection range can be arbitrarily set only by changing the size of the mirror and the number of reflections, and the size of the foreign substance to be detected can be arbitrarily set as well.

  Next, the present invention will be described in detail with reference to the drawings. FIG. 1 is a perspective view showing a first embodiment of the present invention. FIG. 2 is a plan view illustrating an arrangement example of the foreign matter sensor circuit. The housing 2 of the projector 1 is provided with an opening 3, and the opening lens 4 and the projection mirror 5 are arranged to face each other. An image display light 6 generated on a video display element (not shown) is emitted through the aperture lens 4, reflected by the projection mirror 5, and enlarged and projected on the external screen 11. Although not shown in FIG. 1, the housing 2 includes a video display element, a light source (lamp), an image, and the like, which are necessary for configuring the projector, and are composed of, for example, a liquid crystal display element and a DMD panel element. An optical system for guiding display light to the aperture lens is provided. The projection mirror 5 is installed on a lid member (not shown in FIG. 1) that can close the opening 3 of the housing 2, and when the projector is not used, the opening 3 is closed by the lid member. Also good.

  Since the display light 6 hardly spreads (is not enlarged) on the image display element side of the aperture lens 4, the intensity of the display light 6 emitted from the aperture lens 4 is very large, and the display light path. The air is heated and becomes hot. Further, when the display light 6 is blocked by a foreign substance, the temperature rises suddenly and is dangerous. Conversely, when the temperature of the portion from which the display light is emitted is to be lowered, the display light may be spread (larger than the display element), but the opening and the housing become very large. Realistic.

  In the present embodiment, in order to prevent a foreign matter from entering the high temperature portion between the aperture lens 4 and the projection mirror 5 and entering a dangerous state, a foreign matter sensor circuit is provided in the display light path in a range to be detected at a high temperature. Provided. That is, the side wall 7 of the housing 2 is provided with a sensor light emitting unit 8, a sensor light receiving unit 10, and a plurality of mirrors 9 constituting a foreign substance sensor circuit. Sensor light is emitted from the sensor light emitting unit 8 so as to cross the optical path of the display light 6, reflected by the mirror 9 a plurality of times, and received by the sensor light receiving unit 10. Although not shown in FIG. 1, as will be described later, the foreign matter sensor circuit detects that the sensor light has been shut off by the foreign matter and shuts off the lamp, or detects that the foreign matter detection has been released. The projector is equipped with an electric circuit for performing operations such as shutting off the power when the lamp projection is restarted, the display light of the image is projected, and when it is determined that the foreign object detection can be safely released. Yes.

  FIG. 2 is a plan view for explaining an arrangement example (electric circuit is not shown) of the foreign matter sensor circuit. The sensor light emitting unit 8 in FIG. 2 is configured so that the sensor light does not spread using a semiconductor light emitting element such as a semiconductor laser that emits infrared rays or a light emitting diode, or has a certain degree of directivity. For the sensor light receiving unit 10, for example, a semiconductor light receiving element such as a phototransistor or a photodiode is used. The mirror 9 is installed so as to face each other, and the sensor light 12 emitted from the sensor light emitting unit 8 is reflected by the mirror 9 and surely inputted to the sensor light receiving unit 10. The mirror 9 has an adjustment function capable of changing the angle as necessary. The sensor circuit itself may have an angle adjustment function. 1 and 2 show an example in which two mirrors are arranged so as to face each other, the number of mirrors may be increased as necessary.

  If the emission wavelength of the sensor light used in the sensor circuit is a wavelength that is not used in video display applications (not visible light) and the mirror 9 for the sensor circuit is dedicated to it, the mirror 9 is arranged without reflecting the image. As a result, contrast deterioration can be prevented.

  FIG. 3 shows a block diagram of the foreign matter sensor circuit used in the present invention. The foreign matter sensor circuit includes a sensor light emitting unit, a mirror, a sensor light receiving unit, and a sensor detection circuit which is an electric circuit, a lamp control circuit, a timer circuit, and a power supply control circuit. The sensor light from the sensor light emitting unit 8 is efficiently reflected by the mirror 9 and accurately received by the sensor light receiving unit 10. The signal received by the sensor light receiving unit 10 is sent to the sensor detection circuit 13 constituting the electric circuit 18 to detect the presence / absence of sensor light based on the H / L level. For example, if it is normal, it becomes H, and if the sensor light is blocked even at one place, it becomes L without the sensor light, and it is detected that a foreign object has entered.

  When the sensor detection circuit 13 detects that there is no sensor light, the lamp control circuit 14 determines that it is dangerous and shuts off the lamp. The lamp lighting control element is controlled to be forcibly turned off. For example, the lamp is shut off by switching the voltage of the lamp lighting control element with a switch such as a transistor. When the foreign object disappears and the detection is canceled, the lamp control circuit 14 turns on the lamp again to resume projection.

  In addition, a function for muting the image instead of turning off the lamp is also conceivable. When the image is muted, all black is displayed, and the light emitted from the aperture lens 4 disappears, so that the temperature does not rise. Operationally mutes the video output. As an example, it is a control mute for an image switching unit, an OSD (on-screen display) replacement unit, an output unit, or an IC (semiconductor). OSD display is possible by muting before the OSD replacement part.

  Further, the timer circuit 15 monitors the H / L voltage result detected by the sensor detection circuit 13 as no sensor light, such as several times in a few seconds. For example, using the counter (timer circuit function) built in the CPU (semiconductor), the voltage of the result of foreign object intrusion without sensor light is confirmed 10 times per second, and the same voltage result can be obtained for 10 seconds. Judged as dangerous. The monitoring time is arbitrary.

  The power supply control circuit 16 shuts off the power supply according to the danger judgment result of the timer circuit 15. For example, the power ON control terminal voltage is switched by a switch such as a transistor. In addition, it is controlled by an IC (semiconductor) or the like. If the foreign object detection is not canceled when the power is turned on again, the power-on operation is stopped. When a foreign object is detected, an error is displayed (such as a foreign object abnormality display) by an LED or a display panel to warn. In addition, an error display when the function of muting the image is conceivable instead of not lighting is displayed by OSD (on-screen display). Only the original video signal is muted before the OSD is replaced by a video mute caused by a foreign object. As a result, the video signal becomes all black and only the OSD can be displayed, and an error display is projected on the screen for confirmation. This error display has a small size that does not cause the display light to become hot (1/10 or less of the screen size) and brightness that does not become hot (for example, avoiding white and gray).

  As described above in detail, in the present embodiment, foreign matter can be detected by only one sensor circuit, so that it can be realized with a minimum number of parts and is very efficient. Therefore, the number of parts and current consumption can be reduced and the cost can be reduced. In addition, a projector with high brightness has a feature that a projector can be used safely because a sensor circuit is provided to prevent a sudden temperature rise due to foreign matter.

FIG. 4 is a plan view showing a second embodiment of the present invention, and shows only the foreign matter sensor circuit portion. Since the number of mirrors that reflect the sensor light from the sensor light emitting unit varies depending on the detection range and the size of the foreign matter, when the number of reflections increases, not only the number of mirrors is increased, but also as shown in FIG. It is also possible to arrange large mirrors so as to face each other and make several reflection points within one mirror. In the present embodiment, the detection range can be arbitrarily set simply by changing the size of the mirror and the number of reflections. Similarly, the size of a foreign object to be detected can be arbitrarily set.

1 is a perspective view of a projector representing a first embodiment of the present invention. It is a top view for demonstrating the foreign material sensor circuit of the projector showing the 1st Embodiment of this invention. It is a block diagram which shows the foreign material sensor circuit used for this invention. It is a top view for demonstrating the foreign material sensor circuit of the projector showing the 2nd Embodiment of this invention. It is a side view which shows the outline | summary of the projector which has a projection mirror by the conventional opening structure. (A), (b) is the top view and side view of an aperture structure projector currently disclosed by patent document 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Projector 2 Housing | casing 3 Opening part 4 Opening part lens 5 Projection mirror 6 Display light 7 Side wall 8 Sensor light emission part 9 Mirror 10 Sensor light-receiving part 11 External screen 12 Sensor light 13 Sensor detection circuit 14 Lamp control circuit 15 Timer circuit 16 Power supply control Circuit 18 Electrical circuit

Claims (14)

  A projector having an image display element,
  A housing having an opening;
  A foreign matter detector including a light emitting unit that emits sensor light, a light receiving unit that receives the sensor light, and a control unit that controls the projector based on a signal from the light receiving unit;
  The display light of the image generated in the video display element passes through the opening,
  The projector according to claim 1, wherein the sensor light crosses an optical path of the display light passing through the opening.   The projector according to claim 1, further comprising:
  A projector comprising a mirror that reflects the sensor light.   The projector according to claim 2, wherein
  A plurality of mirrors for reflecting the sensor light;
  The projector, wherein the plurality of mirrors are arranged to face each other so as to sandwich the display light passing through the opening.   The projector according to claim 3, wherein
  At least one of the plurality of mirrors reflects the sensor light twice or more.   The projector according to claim 2, wherein
  Two mirrors reflecting the sensor light;
  The two mirrors are arranged to face each other so as to sandwich the display light passing through the opening,
  The projector is characterized in that the sensor light is multiple-reflected between the two mirrors.   The projector according to any one of claims 1 to 5,
  A projection mirror outside the housing;
  The projector, wherein the display light that has passed through the opening is reflected by the projection mirror.   The projector according to claim 6, wherein
  The projection mirror is attached to the projector so as to be able to fall down and cause it, and constitutes a projection optical system in the raised state, and closes the opening in the lowered state.   The projector according to any one of claims 1 to 7,
  The projector according to claim 1, wherein the sensor light is an infrared ray emitted by a semiconductor light emitting element.   The projector according to any one of claims 1 to 8,
  The control unit turns off the lamp when the signal from the sensor light receiving unit indicates that the sensor light is not detected for a predetermined time.   The projector according to claim 9, wherein
  The control unit turns on a lamp when the signal from the sensor light receiving unit indicates detection of the sensor light.   The projector according to any one of claims 1 to 8,
  The projector, wherein the control unit mutes an image when the signal from the sensor light receiving unit indicates that the sensor light is not detected for a predetermined time.   The projector according to claim 11, wherein
  The control unit is configured to mute the video and perform on-screen display when the signal from the sensor light receiving unit indicates that the sensor light is not detected for a predetermined time.   The projector according to claim 12, wherein
  The projector is characterized in that at least a part of the on-screen display is gray.   The projector according to any one of claims 9 to 13, wherein the predetermined time is arbitrary.

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