JP2003270563A - Optical scanning device and optical scanning type image display device - Google Patents

Abstract

(57) [Problem] To provide a small-sized and high-definition optical scanning device which can cope with an increase in size of a screen and greatly improves the degree of freedom of mounting. SOLUTION: A light source 1 finally outputs a scanning light beam for scanning a screen. A light source 2 provided separately from the light source 1 outputs synchronization detection light for controlling the timing of starting and ending scanning. The scanning light beam reflected from the polygon mirror 7 is reflected by the reflection mirror on which the dielectric film is formed. Since a dielectric reflection film having a reflection characteristic of reflecting incident light at a predetermined reflectance is formed on the surface layer of the reflection mirror, the light of the light source 1 and the light of the light source 2 are simultaneously the same from the mirror surface of the polygon mirror 7. Even if it is configured to be reflected on the optical path, the two light beams are separated, that is, the scanning light beam is reflected and transmitted to the galvanometer mirror 6, and the synchronization detection light is transmitted and transmitted to the light receiving unit 5. can do. Thereby, the degree of freedom of mounting around the light sources 1 and 2 and the light receiving section 5 is greatly improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser printer,
The present invention relates to an optical writing device of a laser printer, an optical scanning device used in an optical measuring device, and an optical scanning type image display device, in particular, applying a directional light beam such as a laser beam to a movable mirror surface such as a rotating polygon mirror. The present invention relates to an optical scanning device for reflection scanning and an optical scanning type image display device using the optical scanning device.

[0002]

2. Description of the Related Art Conventionally, an optical scanning device for reflecting and scanning a light beam having a directivity such as a laser beam on a movable mirror surface such as a rotary polygon mirror is used in an optical writing system such as a laser printer or
It is used in a wide range of fields such as optical measuring devices for measuring surface shape and optical scanning image display devices. In such an optical scanning device, it is necessary to synchronously control the relationship between the mirror surface and the light beam in order to perform beam scanning under desired conditions. Therefore, a method is generally known in which the detection light is applied to a mirror surface and the reflected light is received by a light receiving device at a predetermined position to generate a synchronization signal.
In the case of generating the synchronization signal in this way, conventionally, the scanning light beam used for the original scanning is generally used also as the detection light for the synchronization detection. For example, JP-A-200
The "projection display device" of Japanese Unexamined Patent Publication No. 0-194302 discloses, as an invention relating to an optical scanning type image display device, a laser beam modulated by combining two rotary polygon mirrors (polygon mirrors) is horizontally and vertically scanned. When displaying an image by using an optical sensor for each polygon mirror near the position where the laser beam passes, the actual position of the laser beam is detected and the timing of laser emission is synchronized with the rotation of the polygon mirror. The technique to do is shown.

However, the above-mentioned conventional technique has a difficult problem of increasing the size of the device as described later. In recent years, there has been a rapid increase in needs for large screens and high definition of image display devices (displays), and in particular, projection type image display devices (projectors) suitable for large screen display have become rapidly popular. . The optical scanning type image display device is one of such projection type image display devices, and its features are: (1) A clear image can be obtained because a laser beam having a strong directivity is used for drawing. (2) Since the laser light source has an ideal single wavelength spectrum distribution, the color rendering property is excellent, and the like, which makes it possible to display a color image of extremely high quality.

[0004]

By the way, in order to meet the needs for a large screen and high definition of the image display device, the optical scanning image display device is provided with polygon mirrors as many as possible. At the same time, it is required that the effective range used for displaying images on each surface be as wide as possible. However, in the technique disclosed in the above-mentioned Japanese Patent Laid-Open No. 2000-194302, if an attempt is made to perform synchronous detection with a scanning beam at the same time, a certain fixed range of the available effective range within one mirror surface is synchronously detected. Therefore, there is a problem that the range that can be used only for actual scanning (in the case of this conventional technique, image display) is limited and narrowed. Therefore, in order to obtain a sufficient scanning angle, it is necessary to lengthen the projection distance and enlarge the mirror, which causes a problem that the device becomes large and the power for driving the mirror increases. there were. The problem of restriction on the increase in size and the problem of increasing power are particularly important in the image display device.

By the way, the present applicant previously has a plurality of movable mirror surfaces that move relative to the scanning light beam output from the light beam generating means, and sequentially scans the plurality of mirror surfaces to perform the scanning. In an optical scanning device that repeatedly scans a light beam, a synchronization detection light generation unit for generating synchronization detection light is provided separately from the light beam generation unit, and the synchronization detection output from the synchronization detection light generation unit is provided. Light is applied to the same mirror surface as the mirror surface on which the scanning light beam output from the light beam generation means is applied, and the light beam generation means is controlled by the reflected light of the synchronous detection light from the mirror surface. The invention is characterized in that it is configured to obtain a synchronization signal for
597 (hereinafter referred to as "first application").

In the case of the "optical scanning device and the optical scanning type image display device" described in the specification of this prior application, synchronous detection is started on the same mirror surface as the light beam scanning surface to start scanning due to surface error. Although it is intended to prevent a position shift, that is, a synchronization detection error, in the case of miniaturization, the synchronization detection light generation means or the like may block the optical path of the scanning light beam or may be reversed due to system restrictions or the like. In addition, there is a problem that the optical path of the synchronous detection light is blocked, so that there is a problem that the size cannot be sufficiently reduced. FIG. 15 and FIG. 16 show a configuration of a main part when the optical scanning device described in the specification of the prior application is embodied. FIG. 15 is a view of the apparatus seen from the direction of the rotation axis of the polygon mirror, and FIG.
Shows a view as seen from a direction parallel to the rotation surface of the polygon mirror and in which the rotation axis of the vibration of the galvano mirror is perpendicular to the paper surface.

FIGS. 15 and 16 show a reflection mirror 93 for reflecting a scanning light beam from a light source 91 which is a scanning light beam generating means.
The two-dimensional beam is obtained by irradiating the rotating polygon mirror 97 through the mirror and irradiating the reflected light through the reflecting mirror 94 to the galvanometer mirror 96 that vibrates in the direction orthogonal to the rotating surface of the polygon mirror 97. Scanning is performed. In an apparatus having such a configuration, generally, when the galvanometer mirror 96 is to be vibrated at a high speed, a large motor with large power consumption is required as the galvanometer mirror 96 becomes larger. It is required to make the mirror 96 as small as possible. However, for that purpose, it is necessary to shorten the optical path length from the polygon mirror 97 to the galvano mirror 96 as much as possible.
Miniaturization by high-density mounting is required. However,
Light source 92 for synchronous detection when attempting high-density mounting
It becomes difficult to mount the light receiving unit 95 and the light receiving unit 95, and as a result, it has not been possible to achieve a sufficient miniaturization.

For example, strictly speaking, a scanning light beam,
If the incident light path to the mirror surface is different from the synchronous detection light,
Even if the irradiation positions of both sides are the same in a normal surface shape, if there is a shape error on the mirror surface, the irradiation positions of both will be different, so the surface shape error will be reflected in the reflected light path from the mirror surface. Differences will occur. As a result, a scan start position shift occurs, and in some cases, there is a problem that high-precision scanning cannot be performed. Hereinafter, this problem will be described in more detail. FIG. 17 is an optical path diagram showing an optical path of a light beam (scanning beam or synchronous detection light) of the optical scanning device. Specifically, the state where the light beam (incident beam) is incident on the mirror surface A and the virtual mirror surface B provided with a distance d (error) is shown in a superimposed manner. The optical path difference Δx of the reflected light is Δx = 2d
-Sin θ, which depends on the incident angle θ of the beam. That is, when the incident angles θ of the scanning beam and the synchronous detection light on the mirror surface are different, the above equation (Δ
Therefore, the optical path difference Δx calculated from (x = 2d · sin θ) is generated, and Δx generated in the scanning beam cannot be sufficiently compensated by Δx obtained by the synchronous detection. A scan start position shift will occur.

Such a problem also becomes a serious problem in an optical scanning type image display device which displays an image by scanning a modulated scanning light beam horizontally and vertically. For example, when a start position is deviated between scanning lines in horizontal scanning by a polygon mirror, the result appears as image distortion in the vertical direction, resulting in deterioration of image quality. The present invention has been made to solve the above-mentioned problems of the prior art and the invention of the prior application, and it is possible to widen the effective range that contributes to the scanning of each surface of the movable mirror surface and maximize the use of the scanning surface. At the same time, it is possible to prevent the scanning start position from being displaced due to the distortion of the movable mirror surface or the surface-to-surface error, and further to provide a small-sized, low-power-consumption optical scanning image display device. It is an object.

The object of claim 1 of the present invention is, in particular, in an optical scanning device which reflects and scans a light beam on a movable mirror surface such as a Bolgon mirror or a galvanometer mirror, in which an optical path of the synchronous detection light and an optical path of the scanning light beam are provided. Even in the case of overlapping, the synchronization signal generation means or the like performs synchronization detection without blocking the optical path of the scanning light beam, and separates the scanning light beam reflected from the mirror surface from the synchronization detection light. To greatly improve the degree of freedom in mounting a light source and a light-receiving unit that form the light beam generating means and the synchronous detection light generating means, and to provide a compact and high-performance optical scanning device that enables high-density mounting. It is in. Claim 2 of the present invention
The purpose of is to significantly improve the degree of freedom in mounting the light source and the light receiving section that constitute the light beam generating means and the synchronous detection light generating means, which enables high-density mounting and a compact, high-performance optical system. It is to provide a scanning device. It is an object of claim 3 of the present invention to provide, in particular, a concrete means for realizing the light separating means, and the degree of freedom in mounting the light source and the light receiving portion which constitute the light beam generating means and the synchronous detection light generating means. To
It is intended to provide a small-sized and high-performance optical scanning device which enables a high-density mounting by greatly improving the use of the wavelength separating means.

The object of claim 4 of the present invention is to significantly improve the mounting flexibility of the light source and the light receiving part by using the reflection film made of a dielectric material as a concrete means for realizing the light separating means. Another object of the present invention is to provide a compact and high-performance optical scanning device that enables high-density mounting. It is an object of a fifth aspect of the present invention to provide an optical scanning device which further expands the degree of freedom of mounting, achieves size reduction and power consumption reduction, and can be simply manufactured without increasing the number of parts. is there. It is an object of claim 6 of the present invention to provide, in particular, further different concrete implementation means of the light separating means,
(EN) A degree of freedom in mounting a light source and a light receiving section which constitute a light beam generating means and a synchronous detection light generating means is significantly improved, thereby providing a compact and high-performance optical scanning device capable of high-density mounting. It is in.

The object of claim 7 of the present invention is, in particular, to use the optical combining means for making the incident optical path of the synchronous detection light on the mirror surface coincident with the incident optical path of the light beam. The incident light path to the mirror surface of the is made to coincide with the incident light path of the light beam, so that when the scanning light beam and the incident light path to the mirror surface of the synchronous detection light are different, both irradiation positions in the normal surface shape. Even if they match, if there is a shape error or the like on the mirror surface, there will be a difference according to the surface shape error in the reflected light path from the mirror surface due to the difference in the irradiation positions of the two, for example, as described in the specification relating to the aforementioned prior application. The present invention is to provide a small-sized and high-performance optical scanning device that prevents the occurrence of a theoretical inconvenience as seen in the existing optical scanning device, and in principle does not cause a scanning start position shift. In particular, the object of claim 8 of the present invention is to start the light beam scanning at the time when the reception of the synchronous detection light is detected at its leading edge, that is, the incident optical paths of the synchronous detection light and the light beam coincide with each other. If you need to
It is an object of the present invention to provide an optical scanning device which realizes the start of scanning at the earliest possible timing after the synchronization detection and thereby ensures the effective scanning range which is the original purpose.

It is an object of claim 9 of the present invention to set an optical path length of an optical path from the synchronous detection light generating means to the synchronous signal generating means to be equal to or more than an optical path length of an optical path of the light beam. The synchronization detection light beam diameter and the synchronization detection light receiving portion of the synchronization signal generating means have a certain size, and the synchronization detection light intensity changes with time due to such factors as the synchronization detection light. Accuracy depends on the optical path length until the synchronous detection light is reflected from the mirror surface and received by the light receiving section, that is, the synchronization detection accuracy is sufficient if the optical path length is short. It is an object of the present invention to provide a light scanning device provided with a synchronization signal generating means according to required accuracy by solving the problem that cannot be obtained.

An object of claim 10 of the present invention is to provide the above-mentioned optical scanning device so that image distortion does not occur even if there is an error in the movable mirror surface, and high-quality, high-resolution and high-density mounting is achieved. An object of the present invention is to provide an optical scanning type image display device that can be further miniaturized. The object of claim 11 of the present invention is, in particular, the three primary colors of red (R), green (G) and blue (B) which are scanning light beams which are generally used for the wavelength of the synchronous detection light of the optical scanning device. Wavelength required to form a color image using light (that is, R: 620 to 640 nm, G: 520 to 540 nm, B: 440 to 480 nm)
An object of the present invention is to provide an optical scanning type image display device provided with a synchronous detection light generation means capable of detecting a wavelength outside the range. An object of claim 12 of the present invention is, in particular, an optical scanning type image display device provided with a compact and low-priced synchronous detection light generating means,
More specifically, an optical scanning type image display device equipped with a synchronous detection light generation means using a small and inexpensive long-wavelength semiconductor laser diode (LD) that is generally commercially available for communication or for excitation of a solid-state laser. To provide.

[0015]

In order to achieve the above-mentioned object, an optical scanning device according to the present invention sets a light beam output from a light beam generating means relative to the light beam. In a light scanning device that uses a reflected light of the light beam as a scanning light beam when irradiating a moving mirror surface, a synchronization for generating a synchronization detection light provided as a means separate from the light beam generation means. Detection light generation means, synchronization signal generation means for generating a synchronization signal for controlling the light beam generation means by reflected light of the synchronous detection light from the mirror surface, and the scanning light beam reflected from the mirror surface It is characterized by comprising an optical separation means for separating the synchronous detection light. Further, the synchronous detection light generating means of the optical scanning device according to the present invention according to claim 2 generates the synchronous detection light as light having a wavelength different from that of the scanning light beam, and the light separating means is It is characterized in that it has a wavelength separating means for separating the light beam and the synchronous detection light based on the difference in the wavelength of the incident light.

Further, the wavelength separating means of the optical scanning device according to the present invention according to claim 3 has a transmission characteristic of transmitting incident light with a predetermined transmittance and a reflection characteristic of reflecting the incident light with a predetermined reflectance. It is characterized by having a reflective film having both characteristics. An optical scanning device according to a fourth aspect of the present invention is characterized in that the reflection film is a dielectric reflection film. Further, in the optical scanning device according to the present invention described in claim 5, the mirror surface is formed of the reflective film according to claim 3 or 4, and the mirror surface also functions as the light separating means. It is characterized by being configured. Further, the synchronous detection light generating means and the light beam generating means of the optical scanning device according to the present invention described in claim 6 generate polarized beams having different polarizations, and the light separating means is incident. It is characterized in that it is polarization separation means for separating the scanning light beam and the synchronous detection light based on the polarization characteristic of light.

An optical scanning device according to a seventh aspect of the present invention has an optical combining means for making an incident light path of the synchronous detection light on the mirror surface coincide with an incident light path of the light beam. I am trying. Further, the optical scanning device according to the present invention described in claim 8 captures the synchronization signal, and the synchronization signal detects a transition of the synchronization detection light from a “no light reception” state to a “light reception present” state. However, it is characterized by further comprising scanning start timing control means for starting the light beam scanning in synchronization with the transition detection. Further, in the optical scanning device according to the present invention described in claim 9, the optical path length from the synchronous detection light generating means to the synchronous signal generating means is set to be equal to or more than the optical path length of the optical path of the light beam. Is characterized by.

The optical scanning type image display device according to the present invention described in claim 10 is any one of claims 1 to 9.
The image is displayed by modulating the optical beam on the basis of an image signal extracted from an image to be displayed, and displaying the image. Further, in the optical scanning type image display device according to the present invention described in claim 11, the wavelength of the synchronous detection light of the optical scanning device is 420.
It is characterized in that it is less than or equal to nm or greater than or equal to 660 nm. Further, in the optical scanning type image display device according to the present invention described in claim 12, the synchronous detection light generating means of the optical scanning device is provided with a semiconductor laser emitting a synchronous detection light having a wavelength of more than 660 nm. It has a feature.

[0019]

That is, in the optical scanning device according to claim 1 of the present invention, the reflected light of the light beam when the light beam output from the light beam generating means is applied to a mirror surface that moves relatively to the light beam. In the optical scanning device using a scanning light beam as a scanning light beam, a synchronization detection light generation unit for generating synchronization detection light provided as a unit separate from the light beam generation unit, and a reflection of the synchronization detection light from the mirror surface. By providing a synchronization signal generation means for generating a synchronization signal for controlling the light beam generation means by light, and a light separation means for separating the scanning light beam reflected from the mirror surface and the synchronization detection light The degree of freedom in mounting the light source and the light-receiving section that constitute the light beam generating means and the synchronous detection light generating means is significantly improved, which enables high-density mounting and enables a compact and high-performance optical scanning device. And it represents.

An optical scanning device according to a second aspect of the present invention is provided with the synchronous detection light generating means for generating the synchronous detection light as light having a wavelength different from that of the scanning light beam, and the light separating means is provided. By providing a wavelength separation means for separating the light beam and the synchronous detection light on the basis of the difference in the wavelength of the incident light, the mounting of the light source and the light receiving portion constituting the light beam generation means and the synchronous detection light generation means The degree of freedom is greatly improved by a concrete method of the light separating means, which enables high-density mounting and realizes a compact and high-performance optical scanning device. Further, the optical scanning device according to claim 3 of the present invention has a reflection film having both a transmission characteristic for transmitting incident light with a predetermined transmittance and a reflection characteristic for reflecting the incident light with a predetermined reflectance. By providing the wavelength separation means, the degree of freedom in mounting the light source and the light-receiving part that constitute the light beam generation means and the synchronous detection light generation means is greatly improved, which enables high-density mounting and is small in size and high in performance. Optical scanning device.

Further, in the optical scanning device according to a fourth aspect of the present invention, the reflection film is a dielectric reflection film, so that a light source and a light receiving section which constitute the light beam generation means and the synchronization detection light generation means are mounted. The degree of freedom is greatly improved, which enables high-density mounting and realizes a compact and high-performance optical scanning device. An optical scanning device according to claim 5 of the present invention is configured such that the mirror surface is formed of the reflective film according to claim 3 or 4, and the mirror surface also functions as the light separating means. An optical scanning device has been realized which further expands the degree of freedom of mounting, achieves size reduction and power consumption reduction, and can be easily manufactured without increasing the number of components. An optical scanning device according to claim 6 of the present invention is
The synchronous detection light generation means and the light beam generation means,
By configuring to generate polarized beams having different polarizations, and the light separating means is configured to separate the light beam and the synchronous detection light based on the polarization characteristics of the incident light, The degree of freedom in mounting the light source and the light receiving section that make up the beam generating means and the synchronous detection light generating means is greatly improved by using the light separating means based on the polarization characteristics of the incident light, which enables high-density mounting. As a result, a compact and high-performance optical scanning device has been realized.

Further, the optical scanning device according to a seventh aspect of the present invention is provided with an optical combining means for making the incident optical path of the synchronous detection light on the mirror surface coincide with the incident optical path of the light beam, whereby the scanning light is provided. If the incident light paths of the beam and the synchronous detection light to the mirror surface are different, even if the irradiation positions of both are the same in the normal surface shape, if there is a shape error on the mirror surface, the irradiation positions of the two will be different and The occurrence of a difference in accordance with the surface shape error in the reflected optical path of, for example, to prevent the occurrence of a theoretical inconvenience such as seen in the optical scanning device described in the specification of the prior application,
As a result, in principle, a compact and high-performance optical scanning device that does not cause a scanning start position shift is realized. Further, the optical scanning device according to claim 8 of the present invention takes in the synchronization signal output from the synchronization signal generating means, and the synchronization signal is changed from the “no light reception” state to the “light reception present” state of the synchronization detection light. By providing a scanning start timing control means for starting the light beam scanning in synchronization with the transition detection, the light beam scanning is performed at the time when the reception of the synchronous detection light is detected at its leading edge. In other words, the scanning is started at the earliest possible timing after the synchronization detection, which is necessary when the incident optical paths of the synchronization detection light and the light beam are made to coincide with each other, thereby achieving the original purpose. We have realized an optical scanning device that can secure the maximum effective scanning range.

Further, in the optical scanning device according to claim 9 of the present invention, the optical path length from the synchronous detection light generating means to the synchronous signal generating means is set to be equal to or more than the optical path length of the light beam, Due to factors such as the beam diameter of the sync detection light and the sync detection light receiving part of the sync signal generation means having a certain size, and the fluctuation of the intensity of the sync detection light over time, the accuracy of the sync detection is A problem that arises from the general property that the synchronous detection light depends on the optical path length until it is reflected from the mirror surface and received by the light receiving section, that is, if the optical path length is short, sufficient synchronous detection accuracy cannot be obtained. By solving the above problems, an optical scanning device equipped with a synchronization signal generating means according to the required accuracy is realized. Further, an optical scanning type image display device according to claim 10 of the present invention is provided with any one of claims 1 to 9.
The optical scanning device according to any one of the items 1 to 3, wherein the image is displayed by modulating and scanning the light beam based on an image signal extracted from an image to be displayed, whereby a movable mirror surface is displayed. An optical scanning type image display device that realizes high quality, high resolution, high density packaging and further miniaturization without causing image distortion even if there is an error is realized.

Further, the optical scanning type image display device according to claim 11 of the present invention is preferably configured such that the wavelength of the synchronous detection light of the optical scanning device is 420 nm or less, or 660 nm or more. Optical scanning image display device having a synchronous detection light generating means that functions in a different wavelength range, more specifically, a scanning light beam red (R) generally used in the optical scanning image display device, Wavelengths necessary for forming a color image using three primary color lights of green (G) and blue (B) (that is, R: 620 to 640 nm, G: 520 to 540 nm, B: 440 to
The optical scanning type image display device is provided with a synchronous detection light generating means capable of detecting a wavelength outside the range of (480 nm). Further, in the optical scanning type image display device according to claim 12 of the present invention, the synchronous detection light generating means of the optical scanning device comprises:
An optical scanning type image display device provided with a semiconductor laser that emits synchronous detection light having a wavelength of more than 660 nm, and is provided with a compact and low-priced synchronous detection light generation device, more specifically, for communication or solid state. The present invention has realized an optical scanning type image display device equipped with a synchronous detection light generating means using a small and inexpensive long-wavelength semiconductor laser diode (LD) which is generally commercially available for exciting a laser.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION The optical scanning device and the optical scanning type image display device of the present invention will be described below with reference to the drawings based on the embodiments of the present invention. (First Embodiment) FIGS. 1 and 2 show a first embodiment of the present invention.
3A and 3B are a plan view and a front view showing a configuration of a main part of the optical scanning device according to the embodiment of the present invention. The optical scanning device shown in FIG. 1 and FIG. 2 has a light source 1 that emits a light beam to be a scanning light beam and a light source 2 that emits light for synchronization detection, as a main configuration.
, A reflection mirror 3 for reflecting the scanning light beam on the mirror surface of a polygon mirror 7 described later, and a light receiving section 5 for receiving the synchronous detection light.
A galvano mirror 6 for scanning the scanning light beam reflected from the polygon mirror 7 onto the screen via the reflection mirror 4, and a polygon mirror 7 for linearly scanning the light beam output from the light source 1 having eight mirror surfaces. And a galvano motor 8 that applies repetitive displacement to the galvano mirror 6.

The function of the optical scanning device according to this embodiment of the present invention will be described below. The light source 1 produces a scanning light beam as one element of a light beam producing means (not shown). The drive is controlled by a drive signal from a light source drive controller (not shown) described later. As the light source 1, various types of light sources such as a gas laser and a laser diode can be used depending on the use of the optical scanning device of the present invention, and generally, the light source is not limited to a specific type. The polygon mirror 7 is a scanning mirror (rotary polygonal mirror) having eight mirror surfaces, and rotates in the direction of the arrow shown on the side surface of the polygon mirror 7 to linearly scan the light beam output from the light source 1. . On the other hand, the light source 2, which is one element of the synchronization detection light generation means (not shown) provided separately from the above-mentioned light beam generation means, generates synchronization detection light (shown by a chain line in FIG. 1) and drives the light source described later. Control unit B (not shown)
The drive is controlled by the drive signal from the. The light source 2 is also not limited to a particular type, but it is preferable to use a small and inexpensive laser diode.

As shown in FIG. 1, the synchronous detection light emitted from the light source 2 is applied to the mirror surface of the polygon mirror 7 on the irradiation surface of the scanning light beam and the mirror surface in the vicinity thereof. The synchronous detection light reflected from the polygon mirror 7 is received by the light receiving section 5 and converted into an electric signal. A photodiode or the like can be used as the light receiving unit 5. The output signal output from the light receiving unit 5 is amplified by an amplifier (not shown), binarized by a buffer (not shown), and output as a synchronization signal SYNC described later. Further, a synchronous clock generating means (not shown) receives this synchronous signal SYNC and generates and outputs a clock SCLK synchronized with this (clock SC
LK will be described later). In addition, this sync signal SYNC
Is input to a scan start timing control means (not shown) and generates and outputs a scan start signal STA described later. further,
The scan end control means (not shown) measures the scan end timing triggered by the arrival of the scan start signal STA, and generates and outputs the scan end signal STP (not shown).

The above-mentioned light source drive control section A (not shown) is
The signals STA and STP are input to turn on the light source 1 (irradiate the scanning light beam) in synchronization with the scanning start timing, and turn off the light source 1 (shut off the scanning light beam) in synchronization with the scanning end timing. On the other hand, the light source drive control unit B (not shown) also inputs the signals STA and STP, turns on the light source 2 in synchronization with the scanning end timing, and turns off the light source 2 in synchronization with the scanning start timing. . The greatest feature of the present invention is that
That is, the reflection mirror 4 shown in FIG. 2 has a function as a light separating unit. That is, the mirror surface of the reflection mirror 4 is formed of a material such as a dielectric reflection film whose reflectance and transmittance depend on the wavelength of the incident beam. Specifically, the wavelength of the synchronous detection light output from the light source 2 is different from the wavelength of the scanning light beam output from the light source 1, and the mirror surface of the reflection mirror 4 is a wavelength including the scanning light beam. It is assumed that the light in the region is mostly reflected and that the light in the wavelength region including the synchronous detection light has a physical property (dielectric film or the like) having sufficient transmission characteristics.

As a result, even if the optical paths of the scanning light beam and the synchronous detection light overlap, the scanning light beam is returned by the reflection mirror 4 and guided to the galvano mirror 6 as in the conventional optical scanning device. On the other hand, since the synchronous detection light acts so as to pass through the reflection mirror 4, it becomes possible to arrange the light receiving portion 5 of the synchronization detection light behind the reflection mirror 4, and the polygon mirror 7 and the galvano mirror 6 are provided.
The optical path length between and can be greatly shortened as compared with the conventional one, the galvano mirror 6 can be downsized, and the galvano motor 6 can be downsized and the power consumption can be reduced. FIG. 3 is a characteristic graph showing an example of the reflectance characteristic of the dielectric film used for the reflection mirror of the optical scanning device according to the first embodiment of the present invention. In the graph shown in FIG.
The mirror surface of the reflection mirror 4 has a reflectance of nearly 100% for light in the wavelength range near the wavelength λ0 and transmits 60% or more for light in the other wavelength ranges. Therefore,
By setting the wavelength of the scanning beam in the vicinity of λ0 and setting the synchronous detection light to a wavelength in a region where a sufficient transmittance is obtained, the two can be separated.

FIGS. 4 and 5 are a plan view and a front view showing the structure of the main part of the optical scanning device according to the second embodiment of the present invention. The optical scanning device shown in FIGS. 4 and 5 is different from the configuration of the main part of the optical scanning device shown in FIG. 1 in that the arrangement positions of the reflection mirror 4 and the galvano mirror 6 of FIG. In the optical scanning device shown in FIG. 5, the mirror surface is formed of a material such as a dielectric film having a wavelength dependency in reflectance (similar to the mirror surface of the reflection mirror 4 shown in FIG. 1) (in FIG. Is called the galvanometer mirror 36). Therefore, in the optical scanning device shown in FIG.
The galvano mirror 36 also has a function as a light separating means similar to that of the reflecting mirror 4 shown in FIG. 1, that is, it reflects a scanning light beam and scans it on a screen, and transmits a synchronous detection light. Then, the light is guided to the light receiving unit 5. With this configuration, the polygon mirror 7
It is possible to shorten the optical path length between the galvanometer mirror 36 and the galvanometer mirror 36 to the maximum extent, and it is possible to further reduce the size and reduce the power consumption.

FIG. 6 and FIG. 7 show the structure of the main part of the optical scanning device according to the third embodiment of the present invention. Figure 6
The optical scanning device shown in FIG. 7 is different from the configuration of the main part of the optical scanning device shown in FIG. 1 in that the reflection mirror 4 of FIG. 1 is replaced with the deflection beam splitter 44 of FIG. The other constituent elements are the same as those in FIG. 1 except that a polarizing plate 41 is interposed between the light source 2 and the mirror surface of the polygon mirror.
That is, in the optical scanning device shown in FIG. 6 and FIG. 7, polarized light is used as the light separating means, and the scanning light beam and the synchronous detection light are converted into polarized light different from each other by the polarizing plates 41 and 42, respectively. It is incident on the polygon mirror 7. For example, the scanning light beam is s-polarized and the synchronous detection light is
It can be p-polarized. The light reflected from the polygon mirror 7 is guided to a polarization beam splitter 44 provided in place of the reflection mirror 4. The polarization beam splitter 44 reflects, for example, the s-polarized scanning beam and guides it to the galvanometer mirror 46, and transmits the p-polarized synchronous detection light and guides it to the light receiving unit 5.

FIG. 8 and FIG. 9 show the structure of the main part of the optical scanning device according to the fourth embodiment of the present invention. Figure 8
The optical scanning device shown in FIG. 9 has a dichroic mirror 51 interposed between the light source 1 and the reflection mirror 3, and the light source 2 also has a dichroic mirror 51, as compared with the configuration of the main part of the optical scanning device shown in FIG. The other components are the same as those in FIG. 1 except that they are made to enter.
The scanning beam and the synchronous detection light are combined by the dichroic mirror 51 and are incident on the polygon mirror 7 in the same optical path. It is to be noted that the mirror surface of the reflection mirror 4 is naturally formed of a material such as a dielectric film whose reflectance depends on the wavelength of the incident beam, as in FIG. FIG. 10 is a block diagram showing an example of the configuration of the scanning start timing control means of the optical scanning device according to each of the above embodiments of the present invention.

FIG. 11 is a timing chart showing the main operation of the scanning start timing control means of the optical scanning device according to each of the above embodiments of the present invention. In FIG. 10 and FIG. 11, the meanings of the signals denoted by the symbols DTSYN, SCLK and STA are as follows. SYNC: Sync detection light converted into an electrical signal and amplified and binarized, SCLK: Clock synchronized with sync signal SYNC, DTSYN: Detection output of sync signal SYNC with sync clock SCLK, STA: Scan start signal STA . In the optical scanning device shown in FIG. 8 and FIG. 9, since the dichroic mirror 51 acts to match the incident optical paths of the synchronous detection light and the scanning light beam to the mirror surface of the polygon mirror 7, the synchronous detection position has already been detected. The effective scanning period of the beam is approaching. Therefore, if the scanning is not started at the earliest possible timing after the synchronization detection, there arises a problem that the original purpose of ensuring the effective scanning range is hindered.

The scanning start timing control means shown in FIG. 10 basically uses the detection output DTSYN of the synchronization signal SYNC (according to the synchronization clock SCLK) as it is as the scanning start signal STA. As a result, the scanning is started at the earliest possible timing after the synchronization detection. The latch circuit 6
1 and the AND circuit 62 are for defining the pulse width of the scan start signal STA. That is, the signal EN4 transits to the "L" level when the signal DTSYN is detected by the synchronous clock SCLK, and by ANDing this with the signal DTSYN, the pulse width of the scanning start signal STA is defined as one cycle of SCLK. As a result, the synchronization signal SYNC is taken into the scanning start timing control means. Since the synchronization signal SYNC includes information indicating the transition timing of the synchronization detection light from the "no light reception" state to the "light reception" state, the transition timing detected from the synchronization signal SYNC is included in the synchronization signal SYNC. The light beam scanning can be started synchronously.

FIG. 12 shows the structure of the main part of an optical scanning device according to the fifth embodiment of the present invention. The optical scanning device shown in FIG. 12 corresponds to claim 9, and the configuration of the main part is
Compared with the configuration of the main part of the optical scanning device shown in FIG. 1, the synchronous detection light that has passed through the reflection mirror 4 is emitted from the point provided with the reflection mirrors 74, 75, and 76 and the light source 2. The other components are the same as those in FIG. 1 except that the synchronous detection light is superimposed on the projection light axis of the scanning light beam via the prism type mirror 3a. The optical path length from the light source 2 to the light receiving section 5 for the synchronous detection light is set to be equal to or longer than the optical path length of the optical path of the scanning light beam. In this way, the synchronization detection light can be made incident on the light receiving section 5 with a desired optical path length while appropriately bending the optical path, so that the synchronization detection accuracy can be improved without increasing the size of the device. The reflection mirrors for guiding the synchronous detection light to the light receiving section 5 are not limited to the reflection mirrors 74, 75, 76, and in general, an arbitrary number can be installed.

FIG. 13 is a side view showing the configuration of the main part of one embodiment of the optical scanning type image display device according to the present invention. FIG. 14 is a plan view showing the configuration of the main part of the optical scanning image display device according to the embodiment shown in FIG. The optical scanning type image display device shown in FIGS. 13 and 14 according to this embodiment incorporates the configuration of the optical scanning device according to each of the above-described embodiments of the present invention. That is, the light source 82, the polygon mirror 87, and the galvano mirror 8 shown in FIG.
6, the galvano motor 88, and the light receiving portion 85 (see FIG. 14) are, for example, the light source 2, the polygon mirror 7, the galvano mirror 6, and the galvano motor 8 of the optical scanning device according to the first embodiment of the present invention. The same as the light receiving section 5. The laser light sources 821R, 821G, 821B and the optical modulators 822R, 822G, 822B have mirrors 623R, 623G, 623B, a dichroic prism 824, etc., and perform the same function as the light source 1 including the reflection mirror 3 shown in FIG. The light source 82 can be the light source 2 shown in FIG. Also, dichroic mirror 851
Can be the dichroic mirror 51 shown in FIG.

The screen 89 is also a main constituent element of the optical scanning image display apparatus according to this embodiment.
Incidentally, reference numeral 22 shown in FIG. 13 is a polygon motor for rotationally driving the polygon mirror 87. Although illustration of the synchronization system is omitted, it is assumed that the synchronization SYNC, clock SCLK, detection output DTSYN, and scanning start signal STA of the optical scanning device shown in FIGS. In addition, the laser light source 82
Reference numerals 1R, 821G, and 821B are laser light sources that generate laser beams of three primary colors of red, green, and blue, respectively. Various methods such as gas laser and LD can be applied to these light sources. When the scanning start signal STA becomes "H", the image signals ARo, AGo, ABo of the respective colors are output in synchronization with the synchronous clock SCLK. Each of these color laser lights is converted into an optical modulator 822.
Power modulation is performed by R, 822G, and 822B based on the image signal. As these optical modulators, for example, AOM (acousto-optical modulator) or the like can be used.

Three-color laser light sources 821R, 821G, 821B modulated by the three-color image signals ARo, AGo, ABo
Is combined into one scanning laser beam by the dichroic prism 824 acting as a combining prism via the light modulators 822R, 822G, 822B and the mirrors 623a, 623b, and is incident on the polygon mirror 87. The polygon mirror 87 horizontally scans the incident laser light in the horizontal direction. The laser light reflected by the polygon mirror 87 is incident on the galvano mirror 86. The galvano-mirror 86 is a mirror that reciprocates in the vertical direction with respect to the incident laser light, and accordingly, sub-scans the incident laser light in the vertical direction. The laser light reflected by the galvanometer mirror 86 is guided onto the screen 89, whereby a plane image is displayed on the screen 89. When the scanning of one line in the horizontal direction by one surface of the polygon mirror 87 is completed, the scanning end signal STP is "H".
And the image signals ARo, AGo, ABo are all minimum,
Scanning light output is turned off.

As the RGB three-color light source, various wavelength light sources have been commercialized. For example, R: 6
Those with wavelengths of 40 nm, G: 532 nm, B: 460 nm are commercially available and can be used as a light source for image display devices. Further, as the light source 82 of the synchronous detection light, for example, a small and inexpensive infrared laser diode (LD) of 800 to 900 nm is commercially available for measurement devices and control devices, and also for applications such as sensors. It can be used as a light source of synchronous detection light. Further, the galvano mirror 86 can be formed of a dielectric multilayer film in which each mirror surface reflects light in the vicinity of each wavelength of the above-described RGB three-color light and transmits light in the wavelength range of 800 to 900 nm. That is, each layer of this dielectric multilayer film has a reflectance curve as shown in FIG.
It can be configured to have film characteristics such that 0 is each wavelength of the above-mentioned three RGB colors. The synchronous detection light is emitted from the light source 82, and is superposed on the optical axis of the scanning light beam by the dichroic mirror 851. The light receiving portion 85 is arranged behind the galvanometer mirror 86 and at a position corresponding to the scanning start position.
The synchronous detection light transmitted through 6 is received.

[0040]

As described above, according to the first aspect of the invention, when the light beam output from the light beam generating means is applied to the mirror surface which moves relatively to the light beam,
In a light scanning device that uses the reflected light of the light beam as a scanning light beam, a synchronization detection light generation unit for generating synchronization detection light, which is provided as a unit separate from the light beam generation unit, and the synchronization detection light. Sync signal generating means for generating a sync signal for controlling the light beam generating means by the reflected light from the mirror surface, and light separation for separating the scanning light beam reflected from the mirror surface and the synchronous detection light. Since the means is provided, the degree of freedom in mounting the light source and the light-receiving part that constitute the light beam generating means and the synchronous detection light generating means is significantly improved. A scanning device can be provided.

According to a second aspect of the present invention, the synchronous detection light generating means for generating the synchronous detection light as light having a wavelength different from that of the scanning light beam is provided and reflected from the mirror surface. Since the wavelength separating means for separating the light beam and the synchronous detection light on the basis of the difference in the wavelength of the incident light is provided, the light source and the light receiving section constituting the light beam generating means and the synchronous detection light generating means can be freely mounted. It is possible to significantly improve the degree of optical scanning by a specific method of the light separating means, and it is possible to provide a compact and high-performance optical scanning device that enables high-density mounting. Further, according to the invention described in claim 3, the wavelength having a reflection film having both a transmission characteristic of transmitting incident light with a predetermined transmittance and a reflection characteristic of reflecting the incident light with a predetermined reflectance. Since the separation means is provided, the degree of freedom in mounting the light source and the light-receiving section that constitute the light beam generation means and the synchronous detection light generation means can be significantly improved by using the wavelength separation means, and high-density mounting can be achieved. It is possible to provide a compact and high-performance optical scanning device.

According to the fourth aspect of the invention, since the reflecting film is specifically a dielectric reflecting film, the mounting of the light source and the light receiving portion constituting the light beam generating means and the synchronous detection light generating means is implemented. The degree of freedom can be greatly improved by specifically using a reflection film as the wavelength separating means, and a compact and high-performance optical scanning device can be provided which enables high-density mounting. Further, according to the invention of claim 5, the mirror surface is defined by claim 3 or 4.
Since it is formed of the reflective film described above, and the mirror surface also functions as the function of the light splitting means, the degree of freedom in mounting is further expanded, and high-density mounting is possible without increasing the number of parts, and easy manufacturing is possible. Thus, it is possible to provide an optical scanning device that can achieve further miniaturization.
According to a sixth aspect of the present invention, the synchronous detection light generating means and the light beam generating means are configured to generate polarized beams having different polarizations, and the light separating means is Since it is configured to separate the light beam and the synchronous detection light based on the polarization characteristics of the incident light,
It is possible to significantly improve the mounting flexibility and high-density mounting of the light source and the light-receiving unit that form the light beam generating means and the synchronous detection light generating means, and to provide a compact and high-performance optical scanning device. it can.

According to the seventh aspect of the present invention, since the optical combining means is provided to match the incident light path of the synchronous detection light to the mirror surface with the incident light path of the light beam, the scanning light beam When the incident light paths of the synchronous detection light to the mirror surface are different, even if the irradiation positions of the two are the same in the regular surface shape, if there is a shape error etc. on the mirror surface, the irradiation positions of the two will be different and the reflected light path from the mirror surface will be different. It is possible to prevent the theoretical inconveniences that can occur in optical scanning devices, such as differences in surface shape error, and in principle, a small, high-performance optical device that does not cause scanning start position deviation. A scanning device can be provided. Further, claim 8
According to the invention described in (1), the synchronization signal output from the synchronization signal generating means is fetched, and the synchronization signal transition timing from the “no light reception” state to the “light reception” state of the synchronization detection light And a scanning start timing control means for starting the light beam scanning in synchronism with the transition timing detected from the synchronization signal are provided, so that the reception of the synchronous detection light is detected at the leading edge thereof. It is possible to start the light beam scanning, that is, to match the incident optical paths of the synchronous detection light and the scanning light beam, and realize the scanning start at the earliest possible timing after the synchronous detection. It is possible to provide an optical scanning device capable of ensuring the maximum effective scanning range, which is the purpose of the above.

Further, according to the invention of claim 9,
Since the optical path length from the synchronization detection light generation means to the synchronization signal generation means is set to be equal to or longer than the optical path length of the optical path of the light beam, the beam diameter of the synchronization detection light and the synchronization detection light receiving portion of the synchronization signal generation means. Has a certain size, and due to factors such as fluctuations in the intensity of the synchronous detection light over time,
The problem that arises from the general property that the accuracy of synchronous detection depends on the optical path length until the synchronous detection light is reflected from the mirror surface and received by the light receiving unit, that is, the accuracy of synchronous detection when the optical path length is short Therefore, it is possible to solve the problem that it is not sufficiently obtained, and it is possible to provide an optical scanning device provided with a synchronization signal generating means according to required accuracy. According to a tenth aspect of the present invention, the optical scanning device according to any one of the first to ninth aspects, which has a light separating unit that separates the scanning light beam and the synchronous detection light, should be provided. Since the light beam is modulated and scanned based on the image signal extracted from the image to display the image, image distortion does not occur even if there is an error in the movable mirror surface, and high quality, high resolution, and high density mounting is achieved. Thus, it is possible to provide an optical scanning type image display device that can be further miniaturized.

According to the invention described in claim 11,
The wavelength of the synchronous detection light of the optical scanning device is 420 nm or less,
Alternatively, since it is configured to have a wavelength of 660 nm or more, it is generally used in an optical scanning type image display device provided with a synchronous detection light generating means that functions in a suitable wavelength range, more specifically in an optical scanning type image display device. Scanning light beam red
(R), green (G) and blue (B) wavelengths required to form a color image using the three primary color lights (that is, R: 620 ~ 640 nm, G: 520 ~ 5
It is possible to provide an optical scanning type image display device provided with a synchronous detection light generating means capable of detecting a wavelength outside the range of 40 nm, B: 440 to 480 nm). Further, according to the invention of claim 12, since the synchronous detection light generating means of the optical scanning device can be provided with a semiconductor laser which emits the synchronous detection light having a wavelength of more than 660 nm, it is small in size and low in cost. An optical scanning type image display device provided with a synchronous detection light generating means, more specifically, a small and inexpensive long-wavelength semiconductor laser diode (LD) that is generally commercially available for communication and excitation of a solid-state laser. It is possible to provide an optical scanning type image display device provided with a synchronous detection light generation means using the.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration of a main part of an optical scanning device according to a first embodiment of the present invention.

FIG. 2 is a side view showing a schematic configuration of the optical scanning device shown in FIG.

FIG. 3 is a characteristic graph showing an example of reflectance characteristics of a dielectric film used for the reflection mirror of the optical scanning device according to the first embodiment of the present invention.

FIG. 4 is a plan view showing a configuration of a main part of an optical scanning device according to a second embodiment of the present invention.

5 is a side view showing a schematic configuration of the optical scanning device shown in FIG.

FIG. 6 is a plan view showing a configuration of a main part of an optical scanning device according to a third embodiment of the invention.

7 is a side view showing a schematic configuration of the optical scanning device shown in FIG.

FIG. 8 is a plan view showing a configuration of a main part of an optical scanning device according to a fourth embodiment of the present invention.

9 is a side view showing a schematic configuration of the optical scanning device shown in FIG.

FIG. 10 is a block diagram showing a configuration of a scan start timing control unit common to the optical scanning devices according to the above-described embodiments of the present invention.

FIG. 11 is a timing chart showing the main operation of the scan start timing control means common to the optical scanning devices according to the above-described embodiments of the present invention.

FIG. 12 is a plan view showing a configuration of a main part of an optical scanning device according to a fifth embodiment of the present invention.

FIG. 13 is a side view showing a configuration of a main part of one embodiment of the optical scanning image display device according to the present invention.

14 is a plan view showing a main configuration of the optical scanning image display device shown in FIG.

FIG. 15 is a plan view showing a configuration of a main part of an optical scanning device according to a prior application.

16 is a side view of the optical scanning device shown in FIG.

FIG. 17 is an optical path diagram for explaining that an optical path difference occurs when a light beam is reflected by two virtual reflecting surfaces.

[Explanation of symbols]

1 Light source (scanning light beam) 2,82 Light source (Synchronous detection light) 3,74,75,76 Reflection mirror (total reflection type) 4 Reflection mirror (partially transparent) 5 Light receiving part 6 Galvanometer mirror (total reflection type) 36,86 Galvanometer mirror (partially transparent) 7,87 polygon mirror 8,88 galvano motor 41,42 Polarizing plate 44 Polarizing beam splitter 51,851 dichroic mirror 61 Latch circuit 62 AND circuit 89 screen 821R, 821G, 821B laser light source 822R, 822G, 822B optical modulator 824 dichroic prism

Claims (12)

[Claims] 1. An optical scanning device in which the reflected light of the light beam when the light beam output from the light beam generating means is applied to a mirror surface that moves relatively to the light beam is a scanning light beam, Synchronous detection light generation means for generating synchronous detection light provided as a means separate from the light beam generation means, and for controlling the light beam generation means by reflected light from the mirror surface of the synchronous detection light An optical scanning device comprising: a synchronization signal generation unit that generates a synchronization signal; and a light separation unit that separates the scanning light beam reflected from the mirror surface and the synchronization detection light. 2. The synchronous detection light generating means generates the synchronous detection light as light having a wavelength different from that of the scanning light beam, and the light separating means generates the light based on a difference in wavelength of incident light. The optical scanning device according to claim 1, further comprising a wavelength separating unit that separates a beam and the synchronous detection light. 3. The wavelength separating means has a reflection film having both a transmission characteristic of transmitting incident light with a predetermined transmittance and a reflection characteristic of reflecting the incident light with a predetermined reflectance. The optical scanning device according to claim 2. 4. The optical scanning device according to claim 3, wherein the reflection film is a dielectric reflection film. 5. The mirror surface is formed of the reflective film according to claim 3 or 4, and the mirror surface also functions as the light separating means. Item 4. The optical scanning device according to item 4. 6. The synchronous detection light generating means and the light beam generating means generate polarized beams having different polarizations, and the light separating means generates the scanning light beam based on a polarization characteristic of incident light. 2. The optical scanning device according to claim 1, further comprising a polarized light separating unit that separates the light and the synchronous detection light. 7. The optical combining means according to claim 1, further comprising an optical combining means for making an incident optical path of the synchronous detection light on the mirror surface coincide with an incident optical path of the light beam.
The optical scanning device according to the item. 8. The sync signal is taken in, the sync signal detects a transition of the sync detection light from a “no light reception” state to a “light reception present” state, and the light beam is synchronized with the transition detection. 8. The optical scanning device according to claim 7, further comprising scanning start timing control means for starting scanning. 9. The optical path length of the optical path from the synchronous detection light generating means to the synchronous signal generating means is set to be equal to or more than the optical path length of the optical path of the light beam.
The optical scanning device according to any one of 1. 10. The optical scanning device according to any one of claims 1 to 9, wherein the optical beam is modulated and scanned based on an image signal extracted from an image to be displayed,
An optical scanning image display device, which displays the image. 11. The optical scanning image display device according to claim 10, wherein the wavelength of the synchronous detection light of the optical scanning device is 420 nm or less, or 660 nm or more. 12. The optical scanning image display device according to claim 11, wherein the synchronous detection light generating means of the optical scanning device comprises a semiconductor laser that emits the synchronous detection light having a wavelength of more than 660 nm. .