JPS6316546A - Light emitting device - Google Patents

Abstract

PURPOSE:To solve a problem on generation of heat attending on high densification, by using a two-dimensional electron beam source, and setting up a radiation fin, a thermoelectric cooling element and a heating insulating member. CONSTITUTION:In this device, there are provided with an electron beam source 1 being set up in a support member 2 in a two-dimensional manner and emitting an electron beam, a protective member 3 covering the electron beam source 1 and having an emitting aperture 10 for the electron beam, and a light emitting member 4 being set up in and around the emitting aperture 10 as opposed to the electron beam source 1 and excited by the electron beam. In addition, a radiation fin 7 and a thermoelectric clooing element 6 are thermally made stick fast to the electron beam source 1 and the light emitting member 4, or a heating member 8 is thermally made stick fast to the electron beam source 1 and the support member 2 for this source 1, and a heat insulating member 9 is set up between the support member 2 of the electron beam source 1 and another member. With this constitution, a light emitting source comes possible to be formed at the desired position in desired size, thus manufacture of such a high densification light emitting device that is independently drivable comes to fruition.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a light emitting device, and more particularly to a light emitting device in which a light emitting member such as a semiconductor is irradiated with an electron beam and light is emitted from the light emitting member.

C. Summary of Disclosure] This specification and drawings describe a light emitting device that emits light from a light emitting member such as a semiconductor by irradiating an electron beam onto the light emitting member, which emits light with high density by using a two-dimensional electron beam source. The device is realized, and heat dissipation fins, electronic cooling elements,
The present invention discloses a technique for solving the problem of heat generation caused by high density by disposing a heat insulating member.

[Prior Art] Various attempts have been made to excite light with electron beams, and it has become possible to emit light even in semiconductors that cannot be subjected to PM junctions.

[Problems to be solved by the invention] However, the reliability of the electron beam source is poor due to damage to the crystal caused by the high-speed electron beam reaching 300 keV and the inability to arrange the electron beam source in a high density, and there is a risk of damage to the light emitting member. Irradiation was difficult to put into practical use.

Further, in recent years, semiconductor lasers have been widely used for compact discs, but although it is easy to extract a single beam, it is very difficult to extract multiple beams at high density and independently driven.

It is an object of the present invention to eliminate the drawbacks of the above-mentioned conventional examples and at the same time solve the problem of heat generation due to high density, and to provide a one-dimensional or two-dimensional light emitting device with high density and high reliability.

[Means for Solving the Problems] A light emitting device according to the present invention includes an electron beam source that is two-dimensionally arranged on a support member, that emits an electron beam, and an electron beam exit window that covers the electron beam source and that emits an electron beam. and a light-emitting member disposed near the exit window facing the electron beam source and excited by the electron beam, the electron beam source and the light-emitting member having a radiation fin. and an electron cooling element, or a heating member is thermally brought into close contact with the electron beam source and the supporting member of the electron beam source, and a heat insulating member is provided between the supporting member of the electron beam source and other members. It is preferable to arrange this.

[Function] The electron beam source used in the present invention is
No. 274, JP 54-111272 (USP 42
59878), Japanese Patent Application Publication No. 58-15529 (USP 4
303930) and Japanese Patent Laid-Open No. 57-38528, etc., the following solid-state electron beam generator is disclosed.

FIG. 2 is a plan view showing an example of a solid-state electron beam generator. In Figure 2, EXI, EX2゜EX3・
. . are electrodes that perform selection in the X direction, and they pass through the contact area to the highly doped n shadow area MDI.

They are connected to HO2, HO2, . . . , respectively. Further, EY is an electrode in the Y direction, which is also connected to the highly doped p-type path PP via a contact area, and is connected to the electrode EXI.

EX2. EX3... and the electrode EY constitute a matrix. An extraction electrode PE is provided on the substrate 11 via an insulating layer IL, and electron beam sources EBI, HO2,
HO3... is formed.

In the above configuration, the electrodes EXI, EX2゜E
There is a 7-parasitic amplification effect on X3... and electrode EY.
Electrons are emitted from the electron beam sources EBI, HO2, HO3, . . . by applying a voltage that occurs at the n-junction and simultaneously applying a voltage of a certain magnitude to the extraction electrode PE. At this time, electrodes EXI, EX2. EX3...
By appropriately selecting .electrons, electrons can be emitted from a desired electron beam source. The density of an electron beam source with this structure can be up to about 30 beam sources/am, which is sufficient when considering the specifications of a general recording device.

Note that similar effects can be achieved using other electron beam sources such as those that obtain electron emission by applying forward bias to a known PM junction, or those that use a solid-state electron beam source such as a field emission type.

When such high-density electron generating sources are arranged, temperature increases occur at various locations. To prevent this.

In addition to attaching a heat insulating member to the supporting member of the electron beam source, a cooling/heat dissipating member is also attached to one light emitting member.

[Example] Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a longitudinal sectional view showing an example of a light emitting device embodying the present invention. In FIG. 1, the light emitting device has three dimensions in one dimension.
An electron beam source 1 arranged two-dimensionally with a density of 0 beams/loam, and a support member 2 to which the electron beam source 1 is attached.
and a protective member 3 that shields the electron beam source l in a vacuum, and a protective member 3 disposed at a position facing the electron beam source l in close proximity to an exit window lO provided in the protective member 3 for emitting the electron beam, ■-■Compound 1 includes a light-emitting member 4 made of a semiconductor such as GaAs, and the light-emitting member 4 is supported by a support member 5, and the support member 5 includes an electronic cooling element 6 such as a Peltier element and its radiation fins 7. is closely attached. Note that the support member 2 also serves as a heat dissipation member for the electron beam source 1, and the support member 5 also serves as a heat dissipation member for the light emitting member 4.

The electron beam source l is the same as that already explained in FIG. Since it is large compared to the bandgap of action, it is excited to a fairly high energy level in the semiconductor, and the electrons go to the bottom of the conductor, while the protons settle in a metastable state at the top of the valence band and are directly ejected from there. Or, they recombine through impurities and emit light. Here, the laser oscillation conditions are Rexp C(g-α)L]≧1 where the reflectance between the cavities is R1, the absorption coefficient is α, and the cavity length is L, and the gain threshold (gth) is.

At this time, the amount lost as heat is 80% of the input amount.
One of the important points of the present invention, which has been experimentally found to be the above, is the heat treatment.
However, since the electron generating sources are arranged at a high density, the temperature rises and the performance as an electron beam source fluctuates. In order to prevent this, here, the support member 2 of the electron beam source 1 is made to also function as a heat radiating member to absorb heat and release it to the atmosphere. If the capacity of the radiation fins is increased in this way, the temperature change in the electron beam source 1 will be reduced, but a more aggressive measure is bias heating.

When continuous operation is performed from EBI to EBn at the same time, as shown in Figure 3, the type without heat radiation fins becomes A, the type with heat radiation fins becomes B, and the type with bias heating becomes C. The stability of is significantly different. In particular, the effect of bias heating is great, and the bias temperature at this time is preferably near the temperature at which the electron beam source reaches saturation when heat radiation fins are installed and the electron beam source is continuously operated.

FIG. 4 is a longitudinal sectional view showing an example of a bias heating structure. In the same figure, the light emitting device is constructed almost the same as that shown in FIG. 1.

A heater (heating member) 8 is attached to the electron beam source 1, and a heat insulating member 9 is disposed between the support member 2 and the protection member 3 to prevent heat conduction therefrom. Now heater 8
When the electron beam source 1 is heated and a temperature bias is applied, an electron beam is generated as shown in FIG. (Even if 1 is driven, the temperature is maintained at T!, and the difference value from T2 is quite small compared to A and B, and stable electron beam emission can be obtained.

Next, regarding the heat generation on the side of the light emitting member 1, the performance of the light emitting member 4 tends to deteriorate as the temperature rises, so a rise in temperature cannot be said to be desirable, so it is necessary to suppress this as much as possible or absorb the heat generated quickly. Measures need to be taken. Here, the key point is the balance between the need to increase luminous efficiency and heat radiation or heat absorption.

Generally, a heat dissipation member may be provided on the side opposite to the electron beam source l side of the light emitting member 4, but in this embodiment, as a more proactive measure, a support member that also serves as a heat dissipation member is used to keep the temperature constant. A Peltier element is arranged as the electronic cooling element 6 in 5,
By keeping these at lower temperatures, stable operation of the light emitting member 4 is achieved over a long period of time. In this case, temperature control is carried out by providing a thermistor on the support member 5 to constantly detect the temperature, and by applying feedback to the electronic cooling element 6, the temperature of the support member 5 is controlled.The experimental value is 20 ± 0.2 ° C. It has been confirmed that it satisfactorily clears the following conditions and greatly contributes to temperature stability. Although the effect of the heat dissipation member alone makes a considerable contribution, the temperature coefficient of the light emitting member is 0.3 mm in the case of GaAg.
Since a wavelength shift of about /'C is observed and the output has a temperature coefficient with a similar tendency, it is better to install a thermoelectric cooling element when used in demanding applications.

In this embodiment, the light emitting member 4 is thermally coupled to the electronic cooling element 6 via the support member 5 which also serves as a heat dissipation member, but the light emitting member 4 and the electronic cooling element 6 may be directly coupled. Of course you can.

Next, an example in which the light emitting device of the present invention is used as an electrophotographic recording means will be described. FIG. 5 is a partial perspective view showing an example of application to an LED type printer. In Figure 5, the photosensitive drum! 2, a selfoc lens 13 is disposed, and a light emitting device 14 of the present invention is further disposed outside the selfoc lens 13.
is installed.

The difference from the case of using an LED array is that the individual light emission size of the LED array (although it is related to the light emission output) is 2
The limit is about 0 bottles/ml11, which means that LED
The luminous efficiency of the device is as low as 0.1% relative to the input, and most of it is generated as heat.In reality, it is necessary to form about 20 elements/■ in order to suppress thermal, optical, and electrical interference with adjacent elements. This is because it will become. On the other hand, in the light-emitting device of the present invention, since the light-emitting density is determined by the pitch of the electron beam source, it is possible to achieve a rate of 30 wood/rats or more, and a higher-definition pattern can be formed. It is possible to form images with higher definition than inkjet printers, thermal printers, etc.

In the light-emitting member of the above embodiment, there is no difference in the refractive index of light around the internal Fabry-Perot resonator (not shown), so the light output width tends to widen, but the light can be adjusted to the required size. By creating an appropriate refractive index difference of about Δn = 0.05 between a place where waveguide is desired and a place where it is not, the light is confined within the waveguide and a sharp light output size can be obtained. According to this idea, the direction of light emission within the crystal can be arbitrarily selected, and it is only necessary to form a waveguide in a desired direction. That is, it is also possible to emit light in the opposite direction. Note that the refractive index difference can be easily formed by diffusion, ion implantation, or the like.

Further, although different from this embodiment, the light emitting member 4 may be placed in a vacuum created by the protective member 3, and light may be emitted from an exit window made of glass or the like.

[Effects of the Invention] As explained above, according to the present invention, a high-density two-dimensional electron beam source is used and the problem of heat generation is solved, and as a result, a light emitting source can be placed at a desired position and in a desired size. It becomes possible to form. Therefore, it is possible to create a high-density light-emitting device that can be driven independently, and by forming a waveguide, it is possible to regulate and select the light-emitting size, and also to emit light in a desired direction. Detailed and high-quality recording can be achieved.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of the present invention, FIG. 2 is a plan view of an electron beam source of the present invention, FIG. 3 is a temperature curve diagram for one hour, and FIG. 4 is another embodiment of the present invention. FIG. 5 is a perspective view of an application example of the present invention. 1: electron beam source, 2: support member, 3: protection member, 4: light emitting member, 5: support member, 6: electronic cooling element, 7: radiation fin. 8: heating member, 9: heat insulating member, 10: window, ll2 board.

Claims (3)

[Claims] (1) An electron beam source that is two-dimensionally arranged on a support member and emits an electron beam, a protective member that covers the electron beam source and has an electron beam exit window, and an electron beam source that is arranged in the vicinity of the exit window. 1. A light-emitting device comprising: a light-emitting member disposed facing a source and excited by an electron beam. (2) The light-emitting device according to claim 1, characterized in that a radiation fin and an electronic cooling element are thermally bonded to the electron beam source and the light-emitting member. (3) A heating member is thermally attached to the electron beam source and the supporting member of the electron beam source, and a heat insulating member is provided between the supporting member of the electron beam source and other members of the device itself. A light emitting device according to claim 1 or 2.